types.go

// Copyright 2015 The Cockroach Authors.
//
// Use of this software is governed by the Business Source License
// included in the file licenses/BSL.txt.
//
// As of the Change Date specified in that file, in accordance with
// the Business Source License, use of this software will be governed
// by the Apache License, Version 2.0, included in the file
// licenses/APL.txt.

package types

import (
	"bytes"
	"fmt"
	"regexp"
	"runtime/debug"
	"strings"

	"github.com/cockroachdb/cockroach/pkg/geo/geopb"
	"github.com/cockroachdb/cockroach/pkg/sql/lex"
	"github.com/cockroachdb/cockroach/pkg/sql/oidext"
	"github.com/cockroachdb/cockroach/pkg/sql/pgwire/pgcode"
	"github.com/cockroachdb/cockroach/pkg/sql/pgwire/pgerror"
	"github.com/cockroachdb/cockroach/pkg/sql/sem/catid"
	"github.com/cockroachdb/cockroach/pkg/util/errorutil/unimplemented"
	"github.com/cockroachdb/cockroach/pkg/util/protoutil"
	"github.com/cockroachdb/errors"
	"github.com/cockroachdb/redact"
	"github.com/gogo/protobuf/proto"
	"github.com/lib/pq/oid"
)

// T is an instance of a SQL scalar, array, or tuple type. It describes the
// domain of possible values which a column can return, or to which an
// expression can evaluate. The type system does not differentiate between
// nullable and non-nullable types. It is up to the caller to store that
// information separately if it is needed. Here are some example types:
//
//	INT4                     - any 32-bit integer
//	DECIMAL(10, 3)           - any base-10 value with at most 10 digits, with
//	                           up to 3 to right of decimal point
//	FLOAT[]                  - array of 64-bit IEEE 754 floating-point values
//	TUPLE[TIME, VARCHAR(20)] - any pair of values where first value is a time
//	                           of day and the second value is a string having
//	                           up to 20 characters
//
// Fundamentally, a type consists of the following attributes, each of which has
// a corresponding accessor method. Some of these attributes are only defined
// for a subset of types. See the method comments for more details.
//
//	Family        - equivalence group of the type (enumeration)
//	Oid           - Postgres Object ID that describes the type (enumeration)
//	Precision     - maximum accuracy of the type (numeric)
//	Width         - maximum size or scale of the type (numeric)
//	Locale        - location which governs sorting, formatting, etc. (string)
//	ArrayContents - array element type (T)
//	TupleContents - slice of types of each tuple field ([]*T)
//	TupleLabels   - slice of labels of each tuple field ([]string)
//
// Some types are not currently allowed as the type of a column (e.g. nested
// arrays). Other usages of the types package may have similar restrictions.
// Each such caller is responsible for enforcing their own restrictions; it's
// not the concern of the types package.
//
// Implementation-wise, types.T wraps a protobuf-generated InternalType struct.
// The generated protobuf code defines the struct fields, marshals/unmarshals
// them, formats a string representation, etc. Meanwhile, the wrapper types.T
// struct overrides the Marshal/Unmarshal methods in order to map to/from older
// persisted InternalType representations. For example, older versions of
// InternalType (previously called ColumnType) used a VisibleType field to
// represent INT2, whereas newer versions use Width/Oid. Unmarshal upgrades from
// this old format to the new, and Marshal downgrades, thus preserving backwards
// compatibility.
//
// Simple (unary) scalars types
// ----------------------------
//
// | SQL type          | Family         | Oid           | Precision | Width |
// |-------------------|----------------|---------------|-----------|-------|
// | NULL (unknown)    | UNKNOWN        | T_unknown     | 0         | 0     |
// | BOOL              | BOOL           | T_bool        | 0         | 0     |
// | DATE              | DATE           | T_date        | 0         | 0     |
// | TIMESTAMP         | TIMESTAMP      | T_timestamp   | 0         | 0     |
// | INTERVAL          | INTERVAL       | T_interval    | 0         | 0     |
// | TIMESTAMPTZ       | TIMESTAMPTZ    | T_timestamptz | 0         | 0     |
// | OID               | OID            | T_oid         | 0         | 0     |
// | UUID              | UUID           | T_uuid        | 0         | 0     |
// | INET              | INET           | T_inet        | 0         | 0     |
// | TIME              | TIME           | T_time        | 0         | 0     |
// | TIMETZ            | TIMETZ         | T_timetz      | 0         | 0     |
// | JSON              | JSONB          | T_json        | 0         | 0     |
// | JSONB             | JSONB          | T_jsonb       | 0         | 0     |
// |                   |                |               |           |       |
// | BYTES             | BYTES          | T_bytea       | 0         | 0     |
// |                   |                |               |           |       |
// | STRING            | STRING         | T_text        | 0         | 0     |
// | STRING(N)         | STRING         | T_text        | 0         | N     |
// | VARCHAR           | STRING         | T_varchar     | 0         | 0     |
// | VARCHAR(N)        | STRING         | T_varchar     | 0         | N     |
// | CHAR              | STRING         | T_bpchar      | 0         | 1     |
// | CHAR(N)           | STRING         | T_bpchar      | 0         | N     |
// | "char"            | STRING         | T_char        | 0         | 0     |
// | NAME              | STRING         | T_name        | 0         | 0     |
// |                   |                |               |           |       |
// | STRING COLLATE en | COLLATEDSTRING | T_text        | 0         | 0     |
// | STRING(N) COL...  | COLLATEDSTRING | T_text        | 0         | N     |
// | VARCHAR COL...    | COLLATEDSTRING | T_varchar     | 0         | N     |
// | VARCHAR(N) COL... | COLLATEDSTRING | T_varchar     | 0         | N     |
// | CHAR COL...       | COLLATEDSTRING | T_bpchar      | 0         | 1     |
// | CHAR(N) COL...    | COLLATEDSTRING | T_bpchar      | 0         | N     |
// | "char" COL...     | COLLATEDSTRING | T_char        | 0         | 0     |
// |                   |                |               |           |       |
// | DECIMAL           | DECIMAL        | T_decimal     | 0         | 0     |
// | DECIMAL(N)        | DECIMAL        | T_decimal     | N         | 0     |
// | DECIMAL(N,M)      | DECIMAL        | T_decimal     | N         | M     |
// |                   |                |               |           |       |
// | FLOAT8            | FLOAT          | T_float8      | 0         | 0     |
// | FLOAT4            | FLOAT          | T_float4      | 0         | 0     |
// |                   |                |               |           |       |
// | BIT               | BIT            | T_bit         | 0         | 1     |
// | BIT(N)            | BIT            | T_bit         | 0         | N     |
// | VARBIT            | BIT            | T_varbit      | 0         | 0     |
// | VARBIT(N)         | BIT            | T_varbit      | 0         | N     |
// |                   |                |               |           |       |
// | INT,INTEGER       | INT            | T_int8        | 0         | 64    |
// | INT2,SMALLINT     | INT            | T_int2        | 0         | 16    |
// | INT4              | INT            | T_int4        | 0         | 32    |
// | INT8,INT64,BIGINT | INT            | T_int8        | 0         | 64    |
//
// Tuple types
// -----------
//
// These cannot (yet) be used in tables but are used in DistSQL flow
// processors for queries that have tuple-typed intermediate results.
//
// | Field           | Description                                             |
// |-----------------|---------------------------------------------------------|
// | Family          | TupleFamily                                             |
// | Oid             | T_record                                                |
// | TupleContents   | Contains tuple field types (can be recursively defined) |
// | TupleLabels     | Contains labels for each tuple field                    |
//
// Array types
// -----------
//
// | Field           | Description                                             |
// |-----------------|---------------------------------------------------------|
// | Family          | ArrayFamily                                             |
// | Oid             | T__XXX (double underscores), where XXX is the Oid name  |
// |                 | of a scalar type                                        |
// | ArrayContents   | Type of array elements (scalar, array, or tuple)        |
//
// There are two special ARRAY types:
//
// | SQL type          | Family         | Oid           | ArrayContents |
// |-------------------|----------------|---------------|---------------|
// | INT2VECTOR        | ARRAY          | T_int2vector  | Int           |
// | OIDVECTOR         | ARRAY          | T_oidvector   | Oid           |
//
// When these types are themselves made into arrays, the Oids become T__int2vector and
// T__oidvector, respectively.
//
// User defined types
// ------------------
//
// * Enums
// | Field         | Description                                |
// |---------------|--------------------------------------------|
// | Family        | EnumFamily                                 |
// | Oid           | A unique OID generated upon enum creation  |
//
// See types.proto for the corresponding proto definition. Its automatic
// type declaration is suppressed in the proto so that it is possible to
// add additional fields to T without serializing them.
type T struct {
	// InternalType should never be directly referenced outside this package. The
	// only reason it is exported is because gogoproto panics when printing the
	// string representation of an unexported field. This is a problem when this
	// struct is embedded in a larger struct (like a ColumnDescriptor).
	InternalType InternalType

	// Fields that are only populated when hydrating from a user defined
	// type descriptor. It is assumed that a user defined type is only used
	// once its metadata has been hydrated through the process of type resolution.
	TypeMeta UserDefinedTypeMetadata
}

// UserDefinedTypeMetadata contains metadata needed for runtime
// operations on user defined types. The metadata must be read only.
type UserDefinedTypeMetadata struct {
	// Name is the resolved name of this type.
	Name *UserDefinedTypeName

	// EnumData is non-nil iff the metadata is for an ENUM type.
	EnumData *EnumMetadata

	// Version is the descriptor version of the descriptor used to construct
	// this version of the type metadata.
	Version uint32

	// ImplicitRecordType is true if the metadata is for an implicit record type
	// for a table. Note: this can be deleted if we migrate implicit record types
	// to ordinary persisted composite types.
	ImplicitRecordType bool
}

// EnumMetadata is metadata about an ENUM needed for evaluation.
type EnumMetadata struct {
	// PhysicalRepresentations is a slice of the byte array
	// physical representations of enum members.
	PhysicalRepresentations [][]byte
	// LogicalRepresentations is a slice of the string logical
	// representations of enum members.
	LogicalRepresentations []string
	// IsMemberReadOnly holds whether the enum member at index i is
	// read only or not.
	IsMemberReadOnly []bool
	// TODO (rohany): For small enums, having a map would be slower
	//  than just an array. Investigate at what point the tradeoff
	//  should occur, if at all.
}

func (e *EnumMetadata) debugString() string {
	return fmt.Sprintf(
		"PhysicalReps: %v; LogicalReps: %s",
		e.PhysicalRepresentations,
		e.LogicalRepresentations,
	)
}

// UserDefinedTypeName is a struct representing a qualified user defined
// type name. We redefine a common struct from higher level packages. We
// do so because proto will panic if any members of a proto struct are
// private. Rather than expose private members of higher level packages,
// we define a separate type here to be safe.
type UserDefinedTypeName struct {
	Catalog        string
	ExplicitSchema bool
	Schema         string
	Name           string
}

// Basename returns the unqualified name.
func (u UserDefinedTypeName) Basename() string {
	return u.Name
}

// FQName returns the fully qualified name.
func (u UserDefinedTypeName) FQName() string {
	return FormatTypeName(u)
}

// Convenience list of pre-constructed types. Caller code can use any of these
// types, or use the MakeXXX methods to construct a custom type that is not
// listed here (e.g. if a custom width is needed).
var (
	// Unknown is the type of an expression that statically evaluates to NULL.
	// This type should never be returned for an expression that does not *always*
	// evaluate to NULL.
	Unknown = &T{InternalType: InternalType{
		Family: UnknownFamily, Oid: oid.T_unknown, Locale: &emptyLocale}}

	// Bool is the type of a boolean true/false value.
	Bool = &T{InternalType: InternalType{
		Family: BoolFamily, Oid: oid.T_bool, Locale: &emptyLocale}}

	// VarBit is the type of an ordered list of bits (0 or 1 valued), with no
	// specified limit on the count of bits.
	VarBit = &T{InternalType: InternalType{
		Family: BitFamily, Oid: oid.T_varbit, Locale: &emptyLocale}}

	// Int is the type of a 64-bit signed integer. This is the canonical type
	// for IntFamily.
	Int = &T{InternalType: InternalType{
		Family: IntFamily, Width: 64, Oid: oid.T_int8, Locale: &emptyLocale}}

	// Int4 is the type of a 32-bit signed integer.
	Int4 = &T{InternalType: InternalType{
		Family: IntFamily, Width: 32, Oid: oid.T_int4, Locale: &emptyLocale}}

	// Int2 is the type of a 16-bit signed integer.
	Int2 = &T{InternalType: InternalType{
		Family: IntFamily, Width: 16, Oid: oid.T_int2, Locale: &emptyLocale}}

	// Float is the type of a 64-bit base-2 floating-point number (IEEE 754).
	// This is the canonical type for FloatFamily.
	Float = &T{InternalType: InternalType{
		Family: FloatFamily, Width: 64, Oid: oid.T_float8, Locale: &emptyLocale}}

	// Float4 is the type of a 32-bit base-2 floating-point number (IEEE 754).
	Float4 = &T{InternalType: InternalType{
		Family: FloatFamily, Width: 32, Oid: oid.T_float4, Locale: &emptyLocale}}

	// Decimal is the type of a base-10 floating-point number, with no specified
	// limit on precision (number of digits) or scale (digits to right of decimal
	// point).
	Decimal = &T{InternalType: InternalType{
		Family: DecimalFamily, Oid: oid.T_numeric, Locale: &emptyLocale}}

	// String is the type of a Unicode string, with no specified limit on the
	// count of characters. This is the canonical type for StringFamily. It is
	// reported as STRING in SHOW CREATE but "text" in introspection for
	// compatibility with PostgreSQL.
	String = &T{InternalType: InternalType{
		Family: StringFamily, Oid: oid.T_text, Locale: &emptyLocale}}

	// VarChar is equivalent to String, but has a differing OID (T_varchar),
	// which makes it show up differently when displayed. It is reported as
	// VARCHAR in SHOW CREATE and "character varying" in introspection for
	// compatibility with PostgreSQL.
	VarChar = &T{InternalType: InternalType{
		Family: StringFamily, Oid: oid.T_varchar, Locale: &emptyLocale}}

	// QChar is the special "char" type that is a single-character column type.
	// It's used by system tables. It is reported as "char" (with double quotes
	// included) in SHOW CREATE and "char" in introspection for compatibility
	// with PostgreSQL.
	//
	// See https://www.postgresql.org/docs/9.1/static/datatype-character.html
	QChar = &T{InternalType: InternalType{
		Family: StringFamily, Width: 1, Oid: oid.T_char, Locale: &emptyLocale}}

	// Name is a type-alias for String with a different OID (T_name). It is
	// reported as NAME in SHOW CREATE and "name" in introspection for
	// compatibility with PostgreSQL.
	Name = &T{InternalType: InternalType{
		Family: StringFamily, Oid: oid.T_name, Locale: &emptyLocale}}

	// Bytes is the type of a list of raw byte values.
	Bytes = &T{InternalType: InternalType{
		Family: BytesFamily, Oid: oid.T_bytea, Locale: &emptyLocale}}

	// Date is the type of a value specifying year, month, day (with no time
	// component). There is no timezone associated with it. For example:
	//
	//   YYYY-MM-DD
	//
	Date = &T{InternalType: InternalType{
		Family: DateFamily, Oid: oid.T_date, Locale: &emptyLocale}}

	// Time is the type of a value specifying hour, minute, second (with no date
	// component). By default, it has microsecond precision. There is no timezone
	// associated with it. For example:
	//
	//   HH:MM:SS.ssssss
	//
	Time = &T{InternalType: InternalType{
		Family:             TimeFamily,
		Precision:          0,
		TimePrecisionIsSet: false,
		Oid:                oid.T_time,
		Locale:             &emptyLocale,
	}}

	// TimeTZ is the type specifying hour, minute, second and timezone with
	// no date component. By default, it has microsecond precision.
	// For example:
	//
	//   HH:MM:SS.ssssss+-ZZ:ZZ
	TimeTZ = &T{InternalType: InternalType{
		Family:             TimeTZFamily,
		Precision:          0,
		TimePrecisionIsSet: false,
		Oid:                oid.T_timetz,
		Locale:             &emptyLocale,
	}}

	// Timestamp is the type of a value specifying year, month, day, hour, minute,
	// and second, but with no associated timezone. By default, it has microsecond
	// precision. For example:
	//
	//   YYYY-MM-DD HH:MM:SS.ssssss
	//
	Timestamp = &T{InternalType: InternalType{
		Family:             TimestampFamily,
		Precision:          0,
		TimePrecisionIsSet: false,
		Oid:                oid.T_timestamp,
		Locale:             &emptyLocale,
	}}

	// TimestampTZ is the type of a value specifying year, month, day, hour,
	// minute, and second, as well as an associated timezone. By default, it has
	// microsecond precision. For example:
	//
	//   YYYY-MM-DD HH:MM:SS.ssssss+-ZZ:ZZ
	//
	TimestampTZ = &T{InternalType: InternalType{
		Family:             TimestampTZFamily,
		Precision:          0,
		TimePrecisionIsSet: false,
		Oid:                oid.T_timestamptz,
		Locale:             &emptyLocale,
	}}

	// Interval is the type of a value describing a duration of time. By default,
	// it has microsecond precision.
	Interval = &T{InternalType: InternalType{
		Family:                IntervalFamily,
		Precision:             0,
		TimePrecisionIsSet:    false,
		Oid:                   oid.T_interval,
		Locale:                &emptyLocale,
		IntervalDurationField: &IntervalDurationField{},
	}}

	// Jsonb is the type of a JavaScript Object Notation (JSON) value that is
	// stored in a decomposed binary format (hence the "b" in jsonb).
	Jsonb = &T{InternalType: InternalType{
		Family: JsonFamily, Oid: oid.T_jsonb, Locale: &emptyLocale}}

	// Json is the type of a JavaScript Object Notation (JSON) value. At the time
	// of writing, these are stored the same as Jsonb types.
	Json = &T{InternalType: InternalType{
		Family: JsonFamily, Oid: oid.T_json, Locale: &emptyLocale}}

	// Uuid is the type of a universally unique identifier (UUID), which is a
	// 128-bit quantity that is very unlikely to ever be generated again, and so
	// can be relied on to be distinct from all other UUID values.
	Uuid = &T{InternalType: InternalType{
		Family: UuidFamily, Oid: oid.T_uuid, Locale: &emptyLocale}}

	// INet is the type of an IPv4 or IPv6 network address. For example:
	//
	//   192.168.100.128/25
	//   FE80:CD00:0:CDE:1257:0:211E:729C
	//
	INet = &T{InternalType: InternalType{
		Family: INetFamily, Oid: oid.T_inet, Locale: &emptyLocale}}

	// Geometry is the type of a geospatial Geometry object.
	Geometry = &T{
		InternalType: InternalType{
			Family:      GeometryFamily,
			Oid:         oidext.T_geometry,
			Locale:      &emptyLocale,
			GeoMetadata: &GeoMetadata{},
		},
	}

	// Geography is the type of a geospatial Geography object.
	Geography = &T{
		InternalType: InternalType{
			Family:      GeographyFamily,
			Oid:         oidext.T_geography,
			Locale:      &emptyLocale,
			GeoMetadata: &GeoMetadata{},
		},
	}

	// Box2D is the type of a geospatial box2d object.
	Box2D = &T{
		InternalType: InternalType{
			Family: Box2DFamily,
			Oid:    oidext.T_box2d,
			Locale: &emptyLocale,
		},
	}

	// PGLSN is the type representing a PostgreSQL LSN object.
	PGLSN = &T{
		InternalType: InternalType{
			Family: PGLSNFamily,
			Oid:    oid.T_pg_lsn,
			Locale: &emptyLocale,
		},
	}

	// Void is the type representing void.
	Void = &T{
		InternalType: InternalType{
			Family: VoidFamily,
			Oid:    oid.T_void,
			Locale: &emptyLocale,
		},
	}

	// EncodedKey is a special type used internally for passing encoded key data.
	// It behaves similarly to Bytes in most circumstances, except
	// encoding/decoding. It is currently used to pass around inverted index keys,
	// which do not fully encode an object.
	EncodedKey = &T{
		InternalType: InternalType{
			Family: EncodedKeyFamily,
			Oid:    oid.T_unknown,
			Locale: &emptyLocale,
		},
	}

	// TSQuery is the tsquery type, which represents a full text search query.
	TSQuery = &T{
		InternalType: InternalType{
			Family: TSQueryFamily,
			Oid:    oid.T_tsquery,
			Locale: &emptyLocale,
		},
	}

	// TSVector is the tsvector type which represents a document compressed in
	// a form that a tsquery query can operate on.
	TSVector = &T{
		InternalType: InternalType{
			Family: TSVectorFamily,
			Oid:    oid.T_tsvector,
			Locale: &emptyLocale,
		},
	}

	// Scalar contains all types that meet this criteria:
	//
	//   1. Scalar type (no ArrayFamily or TupleFamily types).
	//   2. Non-ambiguous type (no UnknownFamily or AnyFamily types).
	//   3. Canonical type for one of the type families.
	//
	Scalar = []*T{
		Bool,
		Box2D,
		Int,
		Float,
		Decimal,
		Date,
		Timestamp,
		Interval,
		Geography,
		Geometry,
		String,
		Bytes,
		TimestampTZ,
		Oid,
		Uuid,
		INet,
		PGLSN,
		Time,
		TimeTZ,
		Jsonb,
		VarBit,
	}

	// Any is a special type used only during static analysis as a wildcard type
	// that matches any other type, including scalar, array, and tuple types.
	// Execution-time values should never have this type. As an example of its
	// use, many SQL builtin functions allow an input value to be of any type,
	// and so use this type in their static definitions.
	Any = &T{InternalType: InternalType{
		Family: AnyFamily, Oid: oid.T_anyelement, Locale: &emptyLocale}}

	// AnyArray is a special type used only during static analysis as a wildcard
	// type that matches an array having elements of any (uniform) type (including
	// nested array types). Execution-time values should never have this type.
	AnyArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: Any, Oid: oid.T_anyarray, Locale: &emptyLocale}}

	// AnyEnum is a special type only used during static analysis as a wildcard
	// type that matches an possible enum value. Execution-time values should
	// never have this type.
	AnyEnum = &T{InternalType: InternalType{
		Family: EnumFamily, Locale: &emptyLocale, Oid: oid.T_anyenum}}

	// AnyTuple is a special type used only during static analysis as a wildcard
	// type that matches a tuple with any number of fields of any type (including
	// tuple types). Execution-time values should never have this type.
	AnyTuple = &T{InternalType: InternalType{
		Family: TupleFamily, TupleContents: []*T{Any}, Oid: oid.T_record, Locale: &emptyLocale}}

	// AnyTupleArray is a special type used only during static analysis as a wildcard
	// type that matches an array of tuples with any number of fields of any type (including
	// tuple types). Execution-time values should never have this type.
	AnyTupleArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: AnyTuple, Oid: oid.T__record, Locale: &emptyLocale}}

	// AnyCollatedString is a special type used only during static analysis as a
	// wildcard type that matches a collated string with any locale. Execution-
	// time values should never have this type.
	AnyCollatedString = &T{InternalType: InternalType{
		Family: CollatedStringFamily, Oid: oid.T_text, Locale: &emptyLocale}}

	// EmptyTuple is the tuple type with no fields. Note that this is different
	// than AnyTuple, which is a wildcard type.
	EmptyTuple = &T{InternalType: InternalType{
		Family: TupleFamily, Oid: oid.T_record, Locale: &emptyLocale}}

	// StringArray is the type of an array value having String-typed elements.
	StringArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: String, Oid: oid.T__text, Locale: &emptyLocale}}

	// BytesArray is the type of an array value having Byte-typed elements.
	BytesArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: Bytes, Oid: oid.T__bytea, Locale: &emptyLocale}}

	// IntArray is the type of an array value having Int-typed elements.
	IntArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: Int, Oid: oid.T__int8, Locale: &emptyLocale}}

	// FloatArray is the type of an array value having Float-typed elements.
	FloatArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: Float, Oid: oid.T__float8, Locale: &emptyLocale}}

	// DecimalArray is the type of an array value having Decimal-typed elements.
	DecimalArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: Decimal, Oid: oid.T__numeric, Locale: &emptyLocale}}

	// BoolArray is the type of an array value having Bool-typed elements.
	BoolArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: Bool, Oid: oid.T__bool, Locale: &emptyLocale}}

	// UUIDArray is the type of an array value having UUID-typed elements.
	UUIDArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: Uuid, Oid: oid.T__uuid, Locale: &emptyLocale}}

	// DateArray is the type of an array value having Date-typed elements.
	DateArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: Date, Oid: oid.T__date, Locale: &emptyLocale}}

	// PGLSNArray is the type of an array value having PGLSN-typed elements.
	PGLSNArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: PGLSN, Oid: oid.T__pg_lsn, Locale: &emptyLocale}}

	// TimeArray is the type of an array value having Time-typed elements.
	TimeArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: Time, Oid: oid.T__time, Locale: &emptyLocale}}

	// TimeTZArray is the type of an array value having TimeTZ-typed elements.
	TimeTZArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: TimeTZ, Oid: oid.T__timetz, Locale: &emptyLocale}}

	// TimestampArray is the type of an array value having Timestamp-typed elements.
	TimestampArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: Timestamp, Oid: oid.T__timestamp, Locale: &emptyLocale}}

	// TimestampTZArray is the type of an array value having TimestampTZ-typed elements.
	TimestampTZArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: TimestampTZ, Oid: oid.T__timestamptz, Locale: &emptyLocale}}

	// IntervalArray is the type of an array value having Interval-typed elements.
	IntervalArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: Interval, Oid: oid.T__interval, Locale: &emptyLocale}}

	// INetArray is the type of an array value having INet-typed elements.
	INetArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: INet, Oid: oid.T__inet, Locale: &emptyLocale}}

	// VarBitArray is the type of an array value having VarBit-typed elements.
	VarBitArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: VarBit, Oid: oid.T__varbit, Locale: &emptyLocale}}

	// AnyEnumArray is the type of an array value having AnyEnum-typed elements.
	AnyEnumArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: AnyEnum, Oid: oid.T_anyarray, Locale: &emptyLocale}}

	// JSONBArray is the type of an array value having JSONB-typed elements.
	JSONBArray = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: Jsonb, Oid: oid.T__jsonb, Locale: &emptyLocale}}

	// JSONArrayForDecodingOnly is the type of an array value having JSON-typed elements.
	// Note that this struct can only used for decoding an input as we don't fully
	// support the json array yet.
	JSONArrayForDecodingOnly = &T{InternalType: InternalType{
		Family: ArrayFamily, ArrayContents: Json, Oid: oid.T__json, Locale: &emptyLocale}}

	// Int2Vector is a type-alias for an array of Int2 values with a different
	// OID (T_int2vector instead of T__int2). It is a special VECTOR type used
	// by Postgres in system tables. Int2vectors are 0-indexed, unlike normal arrays.
	Int2Vector = &T{InternalType: InternalType{
		Family: ArrayFamily, Oid: oid.T_int2vector, ArrayContents: Int2, Locale: &emptyLocale}}
)

// Unexported wrapper types.
var (
	// typeBit is the SQL BIT type. It is not exported to avoid confusion with
	// the VarBit type, and confusion over whether its default Width is
	// unspecified or is 1. More commonly used instead is the VarBit type.
	typeBit = &T{InternalType: InternalType{
		Family: BitFamily, Oid: oid.T_bit, Locale: &emptyLocale}}

	// typeBpChar is a CHAR type with an unspecified width. "bp" stands for
	// "blank padded". It is not exported to avoid confusion with QChar, as well
	// as confusion over CHAR's default width of 1.
	//
	// It is reported as CHAR in SHOW CREATE and "character" in introspection for
	// compatibility with PostgreSQL.
	typeBpChar = &T{InternalType: InternalType{
		Family: StringFamily, Oid: oid.T_bpchar, Locale: &emptyLocale}}

	// typeQChar is a "char" type with an unspecified width. It is not exported
	// to avoid confusion with QChar. The "char" type should always have a width
	// of one. A "char" type with an unspecified width is only used when the
	// length of a "char" value cannot be determined, for example a placeholder
	// typed as a "char" should have an unspecified width.
	typeQChar = &T{InternalType: InternalType{
		Family: StringFamily, Oid: oid.T_char, Locale: &emptyLocale}}
)

const (
	// Deprecated after 19.1, since it's now represented using the Oid field.
	name Family = 11

	// Deprecated after 19.1, since it's now represented using the Oid field.
	int2vector Family = 200

	// Deprecated after 19.1, since it's now represented using the Oid field.
	oidvector Family = 201

	visibleNONE = 0

	// Deprecated after 2.1, since it's no longer used.
	visibleINTEGER = 1

	// Deprecated after 2.1, since it's now represented using the Width field.
	visibleSMALLINT = 2

	// Deprecated after 2.1, since it's now represented using the Width field.
	visibleBIGINT = 3

	// Deprecated after 2.0, since the original BIT representation was buggy.
	visibleBIT = 4

	// Deprecated after 19.1, since it's now represented using the Width field.
	visibleREAL = 5

	// Deprecated after 2.1, since it's now represented using the Width field.
	visibleDOUBLE = 6

	// Deprecated after 19.1, since it's now represented using the Oid field.
	visibleVARCHAR = 7

	// Deprecated after 19.1, since it's now represented using the Oid field.
	visibleCHAR = 8

	// Deprecated after 19.1, since it's now represented using the Oid field.
	visibleQCHAR = 9

	// Deprecated after 19.1, since it's now represented using the Oid field.
	visibleVARBIT = 10

	// OID returned for the unknown[] array type. PG has no OID for this case.
	unknownArrayOid = 0
)

const (
	// defaultTimePrecision is the default precision to return for time families
	// if time is not set.
	defaultTimePrecision = 6
)

var (
	emptyLocale = ""
)

// MakeScalar constructs a new instance of a scalar type (i.e. not array or
// tuple types) using the provided fields.
func MakeScalar(family Family, o oid.Oid, precision, width int32, locale string) *T {
	t := OidToType[o]
	if family != t.Family() {
		if family != CollatedStringFamily || StringFamily != t.Family() {
			panic(errors.AssertionFailedf("oid %d does not match %s", o, family))
		}
	}
	if family == ArrayFamily || family == TupleFamily {
		panic(errors.AssertionFailedf("cannot make non-scalar type %s", family))
	}
	if family != CollatedStringFamily && locale != "" {
		panic(errors.AssertionFailedf("non-collation type cannot have locale %s", locale))
	}

	timePrecisionIsSet := false
	var intervalDurationField *IntervalDurationField
	var geoMetadata *GeoMetadata
	switch family {
	case IntervalFamily:
		intervalDurationField = &IntervalDurationField{}
		if precision < 0 || precision > 6 {
			panic(errors.AssertionFailedf("precision must be between 0 and 6 inclusive"))
		}
		timePrecisionIsSet = true
	case TimestampFamily, TimestampTZFamily, TimeFamily, TimeTZFamily:
		if precision < 0 || precision > 6 {
			panic(errors.AssertionFailedf("precision must be between 0 and 6 inclusive"))
		}
		timePrecisionIsSet = true
	case DecimalFamily:
		if precision < 0 {
			panic(errors.AssertionFailedf("negative precision is not allowed"))
		}
	default:
		if precision != 0 {
			panic(errors.AssertionFailedf("type %s cannot have precision", family))
		}
	}

	if width < 0 {
		panic(errors.AssertionFailedf("negative width is not allowed"))
	}
	switch family {
	case IntFamily:
		switch width {
		case 16, 32, 64:
		default:
			panic(errors.AssertionFailedf("invalid width %d for IntFamily type", width))
		}
	case FloatFamily:
		switch width {
		case 32, 64:
		default:
			panic(errors.AssertionFailedf("invalid width %d for FloatFamily type", width))
		}
	case DecimalFamily:
		if width > precision {
			panic(errors.AssertionFailedf(
				"decimal scale %d cannot be larger than precision %d", width, precision))
		}
	case StringFamily, BytesFamily, CollatedStringFamily, BitFamily:
		// These types can have any width.
	case GeometryFamily:
		geoMetadata = &GeoMetadata{}
	case GeographyFamily:
		geoMetadata = &GeoMetadata{}
	default:
		if width != 0 {
			panic(errors.AssertionFailedf("type %s cannot have width", family))
		}
	}

	return &T{InternalType: InternalType{
		Family:                family,
		Oid:                   o,
		Precision:             precision,
		TimePrecisionIsSet:    timePrecisionIsSet,
		Width:                 width,
		Locale:                &locale,
		IntervalDurationField: intervalDurationField,
		GeoMetadata:           geoMetadata,
	}}
}

// MakeBit constructs a new instance of the BIT type (oid = T_bit) having the
// given max # bits (0 = unspecified number).
func MakeBit(width int32) *T {
	if width == 0 {
		return typeBit
	}
	if width < 0 {
		panic(errors.AssertionFailedf("width %d cannot be negative", width))
	}
	return &T{InternalType: InternalType{
		Family: BitFamily, Oid: oid.T_bit, Width: width, Locale: &emptyLocale}}
}

// MakeVarBit constructs a new instance of the BIT type (oid = T_varbit) having
// the given max # bits (0 = unspecified number).
func MakeVarBit(width int32) *T {
	if width == 0 {
		return VarBit
	}
	if width < 0 {
		panic(errors.AssertionFailedf("width %d cannot be negative", width))
	}
	return &T{InternalType: InternalType{
		Family: BitFamily, Width: width, Oid: oid.T_varbit, Locale: &emptyLocale}}
}

// MakeString constructs a new instance of the STRING type (oid = T_text) having
// the given max # characters (0 = unspecified number).
func MakeString(width int32) *T {
	if width == 0 {
		return String
	}
	if width < 0 {
		panic(errors.AssertionFailedf("width %d cannot be negative", width))
	}
	return &T{InternalType: InternalType{
		Family: StringFamily, Oid: oid.T_text, Width: width, Locale: &emptyLocale}}
}

// MakeVarChar constructs a new instance of the VARCHAR type (oid = T_varchar)
// having the given max # characters (0 = unspecified number).
func MakeVarChar(width int32) *T {
	if width == 0 {
		return VarChar
	}
	if width < 0 {
		panic(errors.AssertionFailedf("width %d cannot be negative", width))
	}
	return &T{InternalType: InternalType{
		Family: StringFamily, Oid: oid.T_varchar, Width: width, Locale: &emptyLocale}}
}

// MakeChar constructs a new instance of the CHAR type (oid = T_bpchar) having
// the given max # characters (0 = unspecified number).
func MakeChar(width int32) *T {
	if width == 0 {
		return typeBpChar
	}
	if width < 0 {
		panic(errors.AssertionFailedf("width %d cannot be negative", width))
	}
	return &T{InternalType: InternalType{
		Family: StringFamily, Oid: oid.T_bpchar, Width: width, Locale: &emptyLocale}}
}

// oidCanBeCollatedString returns true if the given oid is can be a CollatedString.
func oidCanBeCollatedString(o oid.Oid) bool {
	switch o {
	case oid.T_text, oid.T_varchar, oid.T_bpchar, oid.T_char, oid.T_name:
		return true
	}
	return false
}

// MakeCollatedString constructs a new instance of a CollatedStringFamily type
// that is collated according to the given locale. The new type is based upon
// the given string type, having the same oid and width values. For example:
//
//	STRING      => STRING COLLATE EN
//	VARCHAR(20) => VARCHAR(20) COLLATE EN
func MakeCollatedString(strType *T, locale string) *T {
	if oidCanBeCollatedString(strType.Oid()) {
		return &T{InternalType: InternalType{
			Family: CollatedStringFamily, Oid: strType.Oid(), Width: strType.Width(), Locale: &locale}}
	}
	panic(errors.AssertionFailedf("cannot apply collation to non-string type: %s", strType))
}

// MakeDecimal constructs a new instance of a DECIMAL type (oid = T_numeric)
// that has at most "precision" # of decimal digits (0 = unspecified number of
// digits) and at most "scale" # of decimal digits after the decimal point
// (0 = unspecified number of digits). scale must be <= precision.
func MakeDecimal(precision, scale int32) *T {
	if precision == 0 && scale == 0 {
		return Decimal
	}
	if precision < 0 {
		panic(errors.AssertionFailedf("precision %d cannot be negative", precision))
	}
	if scale < 0 {
		panic(errors.AssertionFailedf("scale %d cannot be negative", scale))
	}
	if scale > precision {
		panic(errors.AssertionFailedf(
			"scale %d cannot be larger than precision %d", scale, precision))
	}
	return &T{InternalType: InternalType{
		Family:    DecimalFamily,
		Oid:       oid.T_numeric,
		Precision: precision,
		Width:     scale,
		Locale:    &emptyLocale,
	}}
}

// MakeTime constructs a new instance of a TIME type (oid = T_time) that has at
// most the given number of fractional second digits.
//
// To use the default precision, use the `Time` variable.
func MakeTime(precision int32) *T {
	return &T{InternalType: InternalType{
		Family:             TimeFamily,
		Oid:                oid.T_time,
		Precision:          precision,
		TimePrecisionIsSet: true,
		Locale:             &emptyLocale,
	}}
}

// MakeTimeTZ constructs a new instance of a TIMETZ type (oid = T_timetz) that
// has at most the given number of fractional second digits.
//
// To use the default precision, use the `TimeTZ` variable.
func MakeTimeTZ(precision int32) *T {
	return &T{InternalType: InternalType{
		Family:             TimeTZFamily,
		Oid:                oid.T_timetz,
		Precision:          precision,
		TimePrecisionIsSet: true,
		Locale:             &emptyLocale,
	}}
}

// MakeGeometry constructs a new instance of a GEOMETRY type (oid = T_geometry)
// that has the given shape and SRID.
func MakeGeometry(shape geopb.ShapeType, srid geopb.SRID) *T {
	// Negative values are promoted to 0.
	if srid < 0 {
		srid = 0
	}
	return &T{InternalType: InternalType{
		Family: GeometryFamily,
		Oid:    oidext.T_geometry,
		Locale: &emptyLocale,
		GeoMetadata: &GeoMetadata{
			ShapeType: shape,
			SRID:      srid,
		},
	}}
}

// MakeGeography constructs a new instance of a geography-related type.
func MakeGeography(shape geopb.ShapeType, srid geopb.SRID) *T {
	// Negative values are promoted to 0.
	if srid < 0 {
		srid = 0
	}
	return &T{InternalType: InternalType{
		Family: GeographyFamily,
		Oid:    oidext.T_geography,
		Locale: &emptyLocale,
		GeoMetadata: &GeoMetadata{
			ShapeType: shape,
			SRID:      srid,
		},
	}}
}

// GeoMetadata returns the GeoMetadata of the type object if it exists.
// This should only exist on Geometry and Geography types.
func (t *T) GeoMetadata() (*GeoMetadata, error) {
	if t.InternalType.GeoMetadata == nil {
		return nil, errors.Newf("GeoMetadata does not exist on type")
	}
	return t.InternalType.GeoMetadata, nil
}

// GeoSRIDOrZero returns the geo SRID of the type object if it exists.
// This should only exist on a subset of Geometry and Geography types.
func (t *T) GeoSRIDOrZero() geopb.SRID {
	if t.InternalType.GeoMetadata != nil {
		return t.InternalType.GeoMetadata.SRID
	}
	return 0
}

var (
	// DefaultIntervalTypeMetadata returns a duration field that is unset,
	// using INTERVAL or INTERVAL ( iconst32 ) syntax instead of INTERVAL
	// with a qualifier afterwards.
	DefaultIntervalTypeMetadata = IntervalTypeMetadata{}
)

// IntervalTypeMetadata is metadata pertinent for intervals.
type IntervalTypeMetadata struct {
	// DurationField represents the duration field definition.
	DurationField IntervalDurationField
	// Precision is the precision to use - note this matches InternalType rules.
	Precision int32
	// PrecisionIsSet indicates whether Precision is explicitly set.
	PrecisionIsSet bool
}

// IsMinuteToSecond returns whether the IntervalDurationField represents
// the MINUTE TO SECOND interval qualifier.
func (m *IntervalDurationField) IsMinuteToSecond() bool {
	return m.FromDurationType == IntervalDurationType_MINUTE &&
		m.DurationType == IntervalDurationType_SECOND
}

// IsDayToHour returns whether the IntervalDurationField represents
// the DAY TO HOUR interval qualifier.
func (m *IntervalDurationField) IsDayToHour() bool {
	return m.FromDurationType == IntervalDurationType_DAY &&
		m.DurationType == IntervalDurationType_HOUR
}

// IntervalTypeMetadata returns the IntervalTypeMetadata for interval types.
func (t *T) IntervalTypeMetadata() (IntervalTypeMetadata, error) {
	if t.Family() != IntervalFamily {
		return IntervalTypeMetadata{}, errors.Newf("cannot call IntervalTypeMetadata on non-intervals")
	}
	return IntervalTypeMetadata{
		DurationField:  *t.InternalType.IntervalDurationField,
		Precision:      t.InternalType.Precision,
		PrecisionIsSet: t.InternalType.TimePrecisionIsSet,
	}, nil
}

// MakeInterval constructs a new instance of a
// INTERVAL type (oid = T_interval) with a duration field.
//
// To use the default precision and field, use the `Interval` variable.
func MakeInterval(itm IntervalTypeMetadata) *T {
	switch itm.DurationField.DurationType {
	case IntervalDurationType_SECOND, IntervalDurationType_UNSET:
	default:
		if itm.PrecisionIsSet {
			panic(errors.Errorf("cannot set precision for duration type %s", itm.DurationField.DurationType))
		}
	}
	if itm.Precision > 0 && !itm.PrecisionIsSet {
		panic(errors.Errorf("precision must be set if Precision > 0"))
	}

	return &T{InternalType: InternalType{
		Family:                IntervalFamily,
		Oid:                   oid.T_interval,
		Locale:                &emptyLocale,
		Precision:             itm.Precision,
		TimePrecisionIsSet:    itm.PrecisionIsSet,
		IntervalDurationField: &itm.DurationField,
	}}
}

// MakeTimestamp constructs a new instance of a TIMESTAMP type that has at most
// the given number of fractional second digits.
//
// To use the default precision, use the `Timestamp` variable.
func MakeTimestamp(precision int32) *T {
	return &T{InternalType: InternalType{
		Family:             TimestampFamily,
		Oid:                oid.T_timestamp,
		Precision:          precision,
		TimePrecisionIsSet: true,
		Locale:             &emptyLocale,
	}}
}

// MakeTimestampTZ constructs a new instance of a TIMESTAMPTZ type that has at
// most the given number of fractional second digits.
//
// To use the default precision, use the `TimestampTZ` variable.
func MakeTimestampTZ(precision int32) *T {
	return &T{InternalType: InternalType{
		Family:             TimestampTZFamily,
		Oid:                oid.T_timestamptz,
		Precision:          precision,
		TimePrecisionIsSet: true,
		Locale:             &emptyLocale,
	}}
}

// MakeEnum constructs a new instance of an EnumFamily type with the given
// stable type ID. Note that it does not hydrate cached fields on the type.
func MakeEnum(typeOID, arrayTypeOID oid.Oid) *T {
	return &T{InternalType: InternalType{
		Family: EnumFamily,
		Oid:    typeOID,
		Locale: &emptyLocale,
		UDTMetadata: &PersistentUserDefinedTypeMetadata{
			ArrayTypeOID: arrayTypeOID,
		},
	}}
}

// MakeArray constructs a new instance of an ArrayFamily type with the given
// element type (which may itself be an ArrayFamily type).
func MakeArray(typ *T) *T {
	// Do not make an array of type unknown[]. Follow Postgres' behavior and
	// convert this to type string[].
	if typ.Family() == UnknownFamily {
		typ = String
	}
	arr := &T{InternalType: InternalType{
		Family:        ArrayFamily,
		Oid:           CalcArrayOid(typ),
		ArrayContents: typ,
		Locale:        &emptyLocale,
	}}
	return arr
}

// MakeTuple constructs a new instance of a TupleFamily type with the given
// field types (some/all of which may be other TupleFamily types).
//
// Warning: the contents slice is used directly; the caller should not modify it
// after calling this function.
func MakeTuple(contents []*T) *T {
	return &T{InternalType: InternalType{
		Family: TupleFamily, Oid: oid.T_record, TupleContents: contents, Locale: &emptyLocale,
	}}
}

// MakeLabeledTuple constructs a new instance of a TupleFamily type with the
// given field types and labels.
func MakeLabeledTuple(contents []*T, labels []string) *T {
	if len(contents) != len(labels) && labels != nil {
		panic(errors.AssertionFailedf(
			"tuple contents and labels must be of same length: %v, %v", contents, labels))
	}
	return &T{InternalType: InternalType{
		Family:        TupleFamily,
		Oid:           oid.T_record,
		TupleContents: contents,
		TupleLabels:   labels,
		Locale:        &emptyLocale,
	}}
}

// NewCompositeType constructs a new instance of a TupleFamily type with the
// given field types and labels, and the given user-defined type OIDs.
func NewCompositeType(typeOID, arrayTypeOID oid.Oid, contents []*T, labels []string) *T {
	if len(contents) != len(labels) && labels != nil {
		panic(errors.AssertionFailedf(
			"tuple contents and labels must be of same length: %v, %v", contents, labels))
	}
	return &T{InternalType: InternalType{
		Family:        TupleFamily,
		Oid:           typeOID,
		TupleContents: contents,
		TupleLabels:   labels,
		Locale:        &emptyLocale,
		UDTMetadata: &PersistentUserDefinedTypeMetadata{
			ArrayTypeOID: arrayTypeOID,
		},
	}}
}

// Family specifies a group of types that are compatible with one another. Types
// in the same family can be compared, assigned, etc., but may differ from one
// another in width, precision, locale, and other attributes. For example, it is
// always an error to insert an INT value into a FLOAT column, because they are
// not in the same family. However, values of different types within the same
// family are "insert-compatible" with one another. Insertion may still result
// in an error because of width overflow or other constraints, but it can at
// least be attempted.
//
// Families are convenient for performing type switches on types, because in
// most cases it is the type family that matters, not the specific type. For
// example, when CRDB encodes values, it maintains routines for each family,
// since types in the same family encode in very similar ways.
//
// Most type families have an associated "canonical type" that is the default
// representative of that family, and which is a superset of all other types in
// that family. Values with other types (in the same family) can always be
// trivially converted to the canonical type with no loss of information. For
// example, the canonical type for IntFamily is Int, which is a 64-bit integer.
// Both 32-bit and 16-bit integers can be trivially converted to it.
//
// Execution operators and functions are permissive in terms of input (allow any
// type within a given family), and typically return only values having
// canonical types as output. For example, the IntFamily Plus operator allows
// values having any IntFamily type as input. But then it will always convert
// those values to 64-bit integers, and return a final 64-bit integer value
// (types.Int). Doing this vastly reduces the required number of operator
// overloads.
func (t *T) Family() Family {
	return t.InternalType.Family
}

// Oid returns the type's Postgres Object ID. The OID identifies the type more
// specifically than the type family, and is used by the Postgres wire protocol
// various Postgres catalog tables, functions like pg_typeof, etc. Maintaining
// the OID is required for Postgres-compatibility.
func (t *T) Oid() oid.Oid {
	return t.InternalType.Oid
}

// Locale identifies a specific geographical, political, or cultural region that
// impacts various character-based operations such as sorting, pattern matching,
// and builtin functions like lower and upper. It is only defined for the
// types in the CollatedStringFamily, and is the empty string for all other
// types.
func (t *T) Locale() string {
	return *t.InternalType.Locale
}

// Width is the size or scale of the type, such as number of bits or characters.
//
//	INT           : # of bits (64, 32, 16)
//	FLOAT         : # of bits (64, 32)
//	DECIMAL       : max # of digits after decimal point (must be <= Precision)
//	STRING        : max # of characters
//	COLLATEDSTRING: max # of characters
//	BIT           : max # of bits
//
// Width is always 0 for other types.
func (t *T) Width() int32 {
	return t.InternalType.Width
}

// Precision is the accuracy of the data type.
//
//	DECIMAL    : max # digits (must be >= Width/Scale)
//	INTERVAL   : max # fractional second digits
//	TIME       : max # fractional second digits
//	TIMETZ     : max # fractional second digits
//	TIMESTAMP  : max # fractional second digits
//	TIMESTAMPTZ: max # fractional second digits
//
// Precision for time-related families has special rules for 0 -- see
// `precision_is_set` on the `InternalType` proto.
//
// Precision is always 0 for other types.
func (t *T) Precision() int32 {
	switch t.InternalType.Family {
	case IntervalFamily, TimestampFamily, TimestampTZFamily, TimeFamily, TimeTZFamily:
		if t.InternalType.Precision == 0 && !t.InternalType.TimePrecisionIsSet {
			return defaultTimePrecision
		}
	}
	return t.InternalType.Precision
}

// TypeModifier returns the type modifier of the type. This corresponds to the
// pg_attribute.atttypmod column. atttypmod records type-specific data supplied
// at table creation time (for example, the maximum length of a varchar column).
// Array types have the same type modifier as the contents of the array.
// The value will be -1 for types that do not need atttypmod.
func (t *T) TypeModifier() int32 {
	if t.Family() == ArrayFamily {
		return t.ArrayContents().TypeModifier()
	}
	// The type modifier for "char" is always -1.
	if t.Oid() == oid.T_char {
		return int32(-1)
	}

	switch t.Family() {
	case StringFamily, CollatedStringFamily:
		if width := t.Width(); width != 0 {
			// Postgres adds 4 to the attypmod for bounded string types, the
			// var header size.
			return width + 4
		}
	case BitFamily:
		if width := t.Width(); width != 0 {
			return width
		}
	case DecimalFamily:
		// attTypMod is calculated by putting the precision in the upper
		// bits and the scale in the lower bits of a 32-bit int, and adding
		// 4 (the var header size). We mock this for clients' sake. See
		// https://github.com/postgres/postgres/blob/5a2832465fd8984d089e8c44c094e6900d987fcd/src/backend/utils/adt/numeric.c#L1242.
		if width, precision := t.Width(), t.Precision(); precision != 0 || width != 0 {
			return ((precision << 16) | width) + 4
		}
	}
	return int32(-1)
}

// WithoutTypeModifiers returns a copy of the given type with the type modifiers
// reset, if the type has modifiers. The returned type has arbitrary width and
// precision, or for some types, like timestamps, the maximum allowed width and
// precision. If the given type already has no type modifiers, it is returned
// unchanged and the function does not allocate a new type.
func (t *T) WithoutTypeModifiers() *T {
	switch t.Family() {
	case ArrayFamily:
		// Remove type modifiers of the array content type.
		newContents := t.ArrayContents().WithoutTypeModifiers()
		if newContents == t.ArrayContents() {
			return t
		}
		return MakeArray(newContents)
	case TupleFamily:
		// Remove type modifiers for each of the tuple content types.
		oldContents := t.TupleContents()
		newContents := make([]*T, len(oldContents))
		changed := false
		for i := range newContents {
			newContents[i] = oldContents[i].WithoutTypeModifiers()
			if newContents[i] != oldContents[i] {
				changed = true
			}
		}
		if !changed {
			return t
		}
		return MakeTuple(newContents)
	case EnumFamily:
		// Enums have no type modifiers.
		return t
	}

	// For types that can be a collated string, we copy the type and set the width
	// to 0 rather than returning the default OidToType type so that we retain the
	// locale value if the type is collated.
	if oidCanBeCollatedString(t.Oid()) {
		newT := *t
		newT.InternalType.Width = 0
		return &newT
	}

	typ, ok := OidToType[t.Oid()]
	if !ok {
		// These special cases for json, json[] is here so we can
		// support decoding parameters with oid=json/json[] without
		// adding full support for these type.
		// TODO(sql-exp): Remove this if we support JSON.
		if t.Oid() == oid.T_json {
			return Jsonb
		}
		if t.Oid() == oid.T__json {
			return JSONArrayForDecodingOnly
		}
		panic(errors.AssertionFailedf("unexpected OID: %d", t.Oid()))
	}
	return typ
}

// Scale is an alias method for Width, used for clarity for types in
// DecimalFamily.
func (t *T) Scale() int32 {
	return t.InternalType.Width
}

// ArrayContents returns the type of array elements. This is nil for types that
// are not in the ArrayFamily.
func (t *T) ArrayContents() *T {
	return t.InternalType.ArrayContents
}

// TupleContents returns a slice containing the type of each tuple field. This
// is nil for non-TupleFamily types.
func (t *T) TupleContents() []*T {
	return t.InternalType.TupleContents
}

// TupleLabels returns a slice containing the labels of each tuple field. This
// is nil for types not in the TupleFamily, or if the tuple type does not
// specify labels.
func (t *T) TupleLabels() []string {
	return t.InternalType.TupleLabels
}

// UserDefinedArrayOID returns the OID of the array type that corresponds to
// this user defined type. This function only can only be called on user
// defined types and returns non-zero data only for user defined types that
// aren't arrays.
func (t *T) UserDefinedArrayOID() oid.Oid {
	if t.InternalType.UDTMetadata == nil {
		return 0
	}
	return t.InternalType.UDTMetadata.ArrayTypeOID
}

// RemapUserDefinedTypeOIDs is used to remap OIDs stored within a types.T
// that is a user defined type. The newArrayOID argument is ignored if the
// input type is an Array type. It mutates the input types.T and should only
// be used when type is known to not be shared. If the input oid values are
// 0 then the RemapUserDefinedTypeOIDs has no effect.
func RemapUserDefinedTypeOIDs(t *T, newOID, newArrayOID oid.Oid) {
	if newOID != 0 {
		t.InternalType.Oid = newOID
	}
	if t.Family() != ArrayFamily && newArrayOID != 0 {
		t.InternalType.UDTMetadata.ArrayTypeOID = newArrayOID
	}
}

// UserDefined returns whether or not t is a user defined type.
func (t *T) UserDefined() bool {
	return IsOIDUserDefinedType(t.Oid())
}

// IsOIDUserDefinedType returns whether or not o corresponds to a user
// defined type.
func IsOIDUserDefinedType(o oid.Oid) bool {
	return catid.IsOIDUserDefined(o)
}

var familyNames = map[Family]string{
	AnyFamily:            "any",
	ArrayFamily:          "array",
	BitFamily:            "bit",
	BoolFamily:           "bool",
	Box2DFamily:          "box2d",
	BytesFamily:          "bytes",
	CollatedStringFamily: "collatedstring",
	DateFamily:           "date",
	DecimalFamily:        "decimal",
	EnumFamily:           "enum",
	FloatFamily:          "float",
	GeographyFamily:      "geography",
	GeometryFamily:       "geometry",
	INetFamily:           "inet",
	IntFamily:            "int",
	IntervalFamily:       "interval",
	JsonFamily:           "jsonb",
	OidFamily:            "oid",
	PGLSNFamily:          "pg_lsn",
	StringFamily:         "string",
	TimeFamily:           "time",
	TimestampFamily:      "timestamp",
	TimestampTZFamily:    "timestamptz",
	TimeTZFamily:         "timetz",
	TSQueryFamily:        "tsquery",
	TSVectorFamily:       "tsvector",
	TupleFamily:          "tuple",
	UnknownFamily:        "unknown",
	UuidFamily:           "uuid",
	VoidFamily:           "void",
	EncodedKeyFamily:     "encodedkey",
}

// Name returns a user-friendly word indicating the family type.
//
// TODO(radu): investigate whether anything breaks if we use
// enumvalue_customname and use String() instead.
func (f Family) Name() string {
	ret, ok := familyNames[f]
	if !ok {
		panic(errors.AssertionFailedf("unexpected Family: %d", f))
	}
	return ret
}

// Name returns a single word description of the type that describes it
// succinctly, but without all the details, such as width, locale, etc. The name
// is sometimes the same as the name returned by SQLStandardName, but is more
// CRDB friendly.
//
// TODO(andyk): Should these be changed to be the same as SQLStandardName?
func (t *T) Name() string {
	switch fam := t.Family(); fam {
	case AnyFamily:
		return "anyelement"

	case ArrayFamily:
		switch t.Oid() {
		case oid.T_oidvector:
			return "oidvector"
		case oid.T_int2vector:
			return "int2vector"
		}
		return t.ArrayContents().Name() + "[]"

	case BitFamily:
		if t.Oid() == oid.T_varbit {
			return "varbit"
		}
		return "bit"

	case FloatFamily:
		switch t.Width() {
		case 64:
			return "float"
		case 32:
			return "float4"
		default:
			panic(errors.AssertionFailedf("programming error: unknown float width: %d", t.Width()))
		}

	case IntFamily:
		switch t.Width() {
		case 64:
			return "int"
		case 32:
			return "int4"
		case 16:
			return "int2"
		default:
			panic(errors.AssertionFailedf("programming error: unknown int width: %d", t.Width()))
		}

	case OidFamily:
		return t.SQLStandardName()

	case StringFamily, CollatedStringFamily:
		switch t.Oid() {
		case oid.T_text:
			return "string"
		case oid.T_bpchar:
			return "char"
		case oid.T_char:
			// Yes, that's the name. The ways of PostgreSQL are inscrutable.
			return `"char"`
		case oid.T_varchar:
			return "varchar"
		case oid.T_name:
			return "name"
		}
		panic(errors.AssertionFailedf("unexpected OID: %d", t.Oid()))

	case TupleFamily:
		return t.SQLStandardName()

	case EnumFamily:
		if t.Oid() == oid.T_anyenum {
			return "anyenum"
		}
		// This can be nil during unit testing.
		if t.TypeMeta.Name == nil {
			return "unknown_enum"
		}
		return t.TypeMeta.Name.Basename()

	default:
		return fam.Name()
	}
}

// PGName returns the Postgres name for the type. This is sometimes different
// than the native CRDB name for it (i.e. the Name function). It is used when
// compatibility with PG is important. Examples of differences:
//
//	Name()       PGName()
//	--------------------------
//	char         bpchar
//	"char"       char
//	bytes        bytea
//	int4[]       _int4
func (t *T) PGName() string {
	name, ok := oidext.TypeName(t.Oid())
	if ok {
		return strings.ToLower(name)
	}

	// For user defined types, return the basename.
	if t.UserDefined() {
		return t.TypeMeta.Name.Basename()
	}

	// Postgres does not have an UNKNOWN[] type. However, CRDB does, so
	// manufacture a name for it.
	if t.Family() != ArrayFamily || t.ArrayContents().Family() != UnknownFamily {
		panic(errors.AssertionFailedf("unknown PG name for oid %d", t.Oid()))
	}
	return "_unknown"
}

// SQLStandardName returns the type's name as it is specified in the SQL
// standard (or by Postgres for any non-standard types). This can be looked up
// for any type in Postgres using a query similar to this:
//
//	SELECT format_type(pg_typeof(1::int)::regtype, NULL)
func (t *T) SQLStandardName() string {
	return t.SQLStandardNameWithTypmod(false, 0)
}

var telemetryNameReplaceRegex = regexp.MustCompile("[^a-zA-Z0-9]")

// TelemetryName returns a name that is friendly for telemetry.
func (t *T) TelemetryName() string {
	return strings.ToLower(telemetryNameReplaceRegex.ReplaceAllString(t.SQLString(), "_"))
}

// SQLStandardNameWithTypmod is like SQLStandardName but it also accepts a
// typmod argument, and a boolean which indicates whether or not a typmod was
// even specified. The expected results of this function should be, in Postgres:
//
//	SELECT format_type('thetype'::regype, typmod)
//
// Generally, what this does with a non-0 typmod is append the scale, precision
// or length of a datatype to the name of the datatype. For example, a
// varchar(20) would appear as character varying(20) when provided the typmod
// value for varchar(20), which happens to be 24.
//
// This function is full of special cases. See backend/utils/adt/format_type.c
// in Postgres.
func (t *T) SQLStandardNameWithTypmod(haveTypmod bool, typmod int) string {
	var buf strings.Builder
	switch t.Family() {
	case AnyFamily:
		return "anyelement"
	case ArrayFamily:
		switch t.Oid() {
		case oid.T_oidvector:
			return "oidvector"
		case oid.T_int2vector:
			return "int2vector"
		}
		// If we have a typemod specified then pass it down when
		// formatting the array type.
		if !haveTypmod {
			return t.ArrayContents().SQLStandardName() + "[]"
		} else {
			ac := t.ArrayContents()
			return ac.SQLStandardNameWithTypmod(haveTypmod, typmod) + "[]"
		}
	case BitFamily:
		if t.Oid() == oid.T_varbit {
			buf.WriteString("bit varying")
		} else {
			buf.WriteString("bit")
		}
		if !haveTypmod || typmod <= 0 {
			return buf.String()
		}
		buf.WriteString(fmt.Sprintf("(%d)", typmod))
		return buf.String()
	case BoolFamily:
		return "boolean"
	case Box2DFamily:
		return "box2d"
	case BytesFamily:
		return "bytea"
	case DateFamily:
		return "date"
	case DecimalFamily:
		if !haveTypmod || typmod <= 0 {
			return "numeric"
		}
		// The typmod of a numeric has the precision in the upper bits and the
		// scale in the lower bits of a 32-bit int, after subtracting 4 (the var
		// header size). See numeric.c.
		typmod -= 4
		return fmt.Sprintf(
			"numeric(%d,%d)",
			(typmod>>16)&0xffff,
			typmod&0xffff,
		)

	case FloatFamily:
		switch t.Width() {
		case 32:
			return "real"
		case 64:
			return "double precision"
		default:
			panic(errors.AssertionFailedf("programming error: unknown float width: %d", t.Width()))
		}
	case GeometryFamily, GeographyFamily:
		return t.Name() + t.InternalType.GeoMetadata.SQLString()
	case INetFamily:
		return "inet"
	case IntFamily:
		switch t.Width() {
		case 16:
			return "smallint"
		case 32:
			// PG shows "integer" for int4.
			return "integer"
		case 64:
			return "bigint"
		default:
			panic(errors.AssertionFailedf("programming error: unknown int width: %d", t.Width()))
		}
	case IntervalFamily:
		// TODO(jordan): intervals can have typmods, but we don't support them in the same way.
		// Masking is used to extract the precision (src/include/utils/timestamp.h), whereas
		// we store it as `IntervalDurationField`.
		return "interval"
	case JsonFamily:
		// Only binary JSON is currently supported.
		return "jsonb"
	case OidFamily:
		switch t.Oid() {
		case oid.T_oid:
			return "oid"
		case oid.T_regclass:
			return "regclass"
		case oid.T_regnamespace:
			return "regnamespace"
		case oid.T_regproc:
			return "regproc"
		case oid.T_regprocedure:
			return "regprocedure"
		case oid.T_regrole:
			return "regrole"
		case oid.T_regtype:
			return "regtype"
		default:
			panic(errors.AssertionFailedf("unexpected Oid: %v", errors.Safe(t.Oid())))
		}
	case PGLSNFamily:
		return "pg_lsn"
	case StringFamily, CollatedStringFamily:
		switch t.Oid() {
		case oid.T_text:
			buf.WriteString("text")
		case oid.T_varchar:
			buf.WriteString("character varying")
		case oid.T_bpchar:
			if haveTypmod && typmod < 0 {
				// Special case. Run `select format_type('bpchar'::regtype, -1);` in pg.
				return "bpchar"
			}
			buf.WriteString("character")
		case oid.T_char:
			// Type modifiers not allowed for "char".
			return `"char"`
		case oid.T_name:
			// Type modifiers not allowed for name.
			return "name"
		default:
			panic(errors.AssertionFailedf("unexpected OID: %d", t.Oid()))
		}
		if !haveTypmod {
			return buf.String()
		}

		// Typmod gets subtracted by 4 for all non-text string-like types to produce
		// the length.
		if t.Oid() != oid.T_text {
			typmod -= 4
		}
		if typmod <= 0 {
			// In this case, we don't print any modifier.
			return buf.String()
		}
		buf.WriteString(fmt.Sprintf("(%d)", typmod))
		return buf.String()

	case TimeFamily:
		if !haveTypmod || typmod < 0 {
			return "time without time zone"
		}
		return fmt.Sprintf("time(%d) without time zone", typmod)
	case TimeTZFamily:
		if !haveTypmod || typmod < 0 {
			return "time with time zone"
		}
		return fmt.Sprintf("time(%d) with time zone", typmod)
	case TimestampFamily:
		if !haveTypmod || typmod < 0 {
			return "timestamp without time zone"
		}
		return fmt.Sprintf("timestamp(%d) without time zone", typmod)
	case TimestampTZFamily:
		if !haveTypmod || typmod < 0 {
			return "timestamp with time zone"
		}
		return fmt.Sprintf("timestamp(%d) with time zone", typmod)
	case TSQueryFamily:
		return "tsquery"
	case TSVectorFamily:
		return "tsvector"
	case TupleFamily:
		if t.UserDefined() {
			// If we have a user-defined tuple type, use its user-defined name.
			return t.TypeMeta.Name.Basename()
		}
		return "record"
	case UnknownFamily:
		return "unknown"
	case UuidFamily:
		return "uuid"
	case VoidFamily:
		return "void"
	case EnumFamily:
		return t.TypeMeta.Name.Basename()
	default:
		panic(errors.AssertionFailedf("unexpected Family: %v", errors.Safe(t.Family())))
	}
}

// InformationSchemaName returns the string suitable to populate the data_type
// column of information_schema.columns.
//
// This is different from SQLString() in that it must report SQL standard names
// that are compatible with PostgreSQL client expectations.
func (t *T) InformationSchemaName() string {
	// This is the same as SQLStandardName, except for the case of arrays.
	if t.Family() == ArrayFamily {
		return "ARRAY"
	}
	// TypeMeta attributes are populated only when it is user defined type.
	if t.TypeMeta.Name != nil {
		return "USER-DEFINED"
	}
	return t.SQLStandardName()
}

// SQLString returns the CockroachDB native SQL string that can be used to
// reproduce the type via parsing the string as a type. It is used in error
// messages and also to produce the output of SHOW CREATE.
func (t *T) SQLString() string {
	switch t.Family() {
	case BitFamily:
		o := t.Oid()
		typName := "BIT"
		if o == oid.T_varbit {
			typName = "VARBIT"
		}
		// BIT(1) pretty-prints as just BIT.
		if (o != oid.T_varbit && t.Width() > 1) ||
			(o == oid.T_varbit && t.Width() > 0) {
			typName = fmt.Sprintf("%s(%d)", typName, t.Width())
		}
		return typName
	case IntFamily:
		switch t.Width() {
		case 16:
			return "INT2"
		case 32:
			return "INT4"
		case 64:
			return "INT8"
		default:
			panic(errors.AssertionFailedf("programming error: unknown int width: %d", t.Width()))
		}
	case StringFamily:
		return t.stringTypeSQL()
	case CollatedStringFamily:
		return t.collatedStringTypeSQL(false /* isArray */)
	case FloatFamily:
		const realName = "FLOAT4"
		const doubleName = "FLOAT8"
		if t.Width() == 32 {
			return realName
		}
		return doubleName
	case DecimalFamily:
		if t.Precision() > 0 {
			if t.Width() > 0 {
				return fmt.Sprintf("DECIMAL(%d,%d)", t.Precision(), t.Scale())
			}
			return fmt.Sprintf("DECIMAL(%d)", t.Precision())
		}
	case JsonFamily:
		// Only binary JSON is currently supported.
		return "JSONB"
	case TimestampFamily, TimestampTZFamily, TimeFamily, TimeTZFamily:
		if t.InternalType.Precision > 0 || t.InternalType.TimePrecisionIsSet {
			return fmt.Sprintf("%s(%d)", strings.ToUpper(t.Name()), t.Precision())
		}
	case GeometryFamily, GeographyFamily:
		return strings.ToUpper(t.Name() + t.InternalType.GeoMetadata.SQLString())
	case IntervalFamily:
		switch t.InternalType.IntervalDurationField.DurationType {
		case IntervalDurationType_UNSET:
			if t.InternalType.Precision > 0 || t.InternalType.TimePrecisionIsSet {
				return fmt.Sprintf("%s(%d)", strings.ToUpper(t.Name()), t.Precision())
			}
		default:
			fromStr := ""
			if t.InternalType.IntervalDurationField.FromDurationType != IntervalDurationType_UNSET {
				fromStr = fmt.Sprintf("%s TO ", t.InternalType.IntervalDurationField.FromDurationType.String())
			}
			precisionStr := ""
			if t.InternalType.Precision > 0 || t.InternalType.TimePrecisionIsSet {
				precisionStr = fmt.Sprintf("(%d)", t.Precision())
			}
			return fmt.Sprintf(
				"%s %s%s%s",
				strings.ToUpper(t.Name()),
				fromStr,
				t.InternalType.IntervalDurationField.DurationType.String(),
				precisionStr,
			)
		}
	case OidFamily:
		if name, ok := oidext.TypeName(t.Oid()); ok {
			return name
		}
	case ArrayFamily:
		switch t.Oid() {
		case oid.T_oidvector:
			return "OIDVECTOR"
		case oid.T_int2vector:
			return "INT2VECTOR"
		}
		if t.ArrayContents().Family() == CollatedStringFamily {
			return t.ArrayContents().collatedStringTypeSQL(true /* isArray */)
		}
		return t.ArrayContents().SQLString() + "[]"
	case EnumFamily:
		if t.Oid() == oid.T_anyenum {
			return "anyenum"
		}
		// We do not expect to be in a situation where we want to format a
		// user-defined type to a string and do not have the TypeMeta hydrated,
		// but there have been bugs in the past, and returning a less informative
		// string is better than a nil-pointer panic.
		if t.TypeMeta.Name == nil {
			return fmt.Sprintf("@%d", t.Oid())
		}
		return t.TypeMeta.Name.FQName()
	}
	return strings.ToUpper(t.Name())
}

// SQLStringForError returns a version of SQLString that will preserve safe
// information during redaction. It is suitable for usage in error messages.
func (t *T) SQLStringForError() redact.RedactableString {
	if t.UserDefined() {
		// Show the redacted SQLString output with an un-redacted prefix to indicate
		// that the type is user defined (and possibly enum or record).
		prefix := "TYPE"
		switch t.Family() {
		case EnumFamily:
			prefix = "ENUM"
		case TupleFamily:
			prefix = "RECORD"
		case ArrayFamily:
			prefix = "ARRAY"
		}
		return redact.Sprintf("USER DEFINED %s: %s", redact.Safe(prefix), t.SQLString())
	}
	switch t.Family() {
	case EnumFamily, TupleFamily, ArrayFamily:
		// These types can be or can contain user-defined types, but the SQLString
		// is safe when they are not user-defined. We filtered out the user-defined
		// case above.
		return redact.Sprint(redact.Safe(t.SQLString()))
	case BoolFamily, IntFamily, FloatFamily, DecimalFamily, DateFamily, TimestampFamily,
		IntervalFamily, StringFamily, BytesFamily, TimestampTZFamily, CollatedStringFamily, OidFamily,
		UnknownFamily, UuidFamily, INetFamily, TimeFamily, JsonFamily, TimeTZFamily, BitFamily,
		GeometryFamily, GeographyFamily, Box2DFamily, VoidFamily, EncodedKeyFamily, TSQueryFamily,
		TSVectorFamily, AnyFamily, PGLSNFamily:
		// These types do not contain other types, and do not require redaction.
		return redact.Sprint(redact.SafeString(t.SQLString()))
	}
	// Default to redaction for unhandled types.
	return redact.Sprint(t.SQLString())
}

// FormatTypeName is an injected dependency from tree to properly format a
// type name. The logic for proper formatting lives in the tree package.
var FormatTypeName = fallbackFormatTypeName

func fallbackFormatTypeName(UserDefinedTypeName) string {
	return "formatting logic has not been injected from tree"
}

// Equivalent returns true if this type is "equivalent" to the given type.
// Equivalent types are compatible with one another: they can be compared,
// assigned, and unioned. Equivalent types must always have the same type family
// for the root type and any descendant types (i.e. in case of array or tuple
// types). Types in the CollatedStringFamily must have the same locale. But
// other attributes of equivalent types, such as width, precision, and oid, can
// be different.
//
// Wildcard types (e.g. Any, AnyArray, AnyTuple, etc) have special equivalence
// behavior. AnyFamily types match any other type, including other AnyFamily
// types. And a wildcard collation (empty string) matches any other collation.
func (t *T) Equivalent(other *T) bool {
	if t.Family() == AnyFamily || other.Family() == AnyFamily {
		return true
	}
	if t.Family() != other.Family() {
		return false
	}

	switch t.Family() {
	case CollatedStringFamily:
		// CockroachDB differs from Postgres by comparing collation names
		// case-insensitively and equating hyphens/underscores.
		if t.Locale() != "" && other.Locale() != "" {
			if !lex.LocaleNamesAreEqual(t.Locale(), other.Locale()) {
				return false
			}
		}

	case TupleFamily:
		// If either tuple is the wildcard tuple, it's equivalent to any other
		// tuple type. This allows overloads to specify that they take an arbitrary
		// tuple type.
		if IsWildcardTupleType(t) || IsWildcardTupleType(other) {
			return true
		}
		if len(t.TupleContents()) != len(other.TupleContents()) {
			return false
		}
		for i := range t.TupleContents() {
			if !t.TupleContents()[i].Equivalent(other.TupleContents()[i]) {
				return false
			}
		}

	case ArrayFamily:
		if !t.ArrayContents().Equivalent(other.ArrayContents()) {
			return false
		}

	case EnumFamily:
		// If one of the types is anyenum, then allow the comparison to
		// go through -- anyenum is used when matching overloads.
		if t.Oid() == oid.T_anyenum || other.Oid() == oid.T_anyenum {
			return true
		}
		if t.Oid() != other.Oid() {
			return false
		}
	}

	return true
}

// EquivalentOrNull is the same as Equivalent, except it returns true if:
// * `t` is Unknown (i.e., NULL) AND (allowNullTupleEquivalence OR `other` is not a tuple),
// * `t` is a tuple with all non-Unknown elements matching the types in `other`.
func (t *T) EquivalentOrNull(other *T, allowNullTupleEquivalence bool) bool {
	// Check normal equivalency first, then check for Null
	normalEquivalency := t.Equivalent(other)
	if normalEquivalency {
		return true
	}

	switch t.Family() {
	case UnknownFamily:
		return allowNullTupleEquivalence || other.Family() != TupleFamily

	case TupleFamily:
		if other.Family() != TupleFamily {
			return false
		}
		// If either tuple is the wildcard tuple, it's equivalent to any other
		// tuple type. This allows overloads to specify that they take an arbitrary
		// tuple type.
		if IsWildcardTupleType(t) || IsWildcardTupleType(other) {
			return true
		}
		if len(t.TupleContents()) != len(other.TupleContents()) {
			return false
		}
		for i := range t.TupleContents() {
			if !t.TupleContents()[i].EquivalentOrNull(other.TupleContents()[i], allowNullTupleEquivalence) {
				return false
			}
		}
		return true

	default:
		return normalEquivalency
	}
}

// Identical returns true if every field in this ColumnType is exactly the same
// as every corresponding field in the given ColumnType. Identical performs a
// deep comparison, traversing any Tuple or Array contents.
//
// NOTE: Consider whether the desired semantics really require identical types,
// or if Equivalent is the right method to call instead.
func (t *T) Identical(other *T) bool {
	return t.InternalType.Identical(&other.InternalType)
}

// Equal is for use in generated protocol buffer code only.
func (t *T) Equal(other *T) bool {
	return t.Identical(other)
}

// Size returns the size, in bytes, of this type once it has been marshaled to
// a byte buffer. This is typically called to determine the size of the buffer
// that needs to be allocated before calling Marshal.
//
// Marshal is part of the protoutil.Message interface.
func (t *T) Size() (n int) {
	// Need to first downgrade the type before delegating to InternalType,
	// because Marshal will downgrade.
	temp := *t
	err := temp.downgradeType()
	if err != nil {
		panic(errors.NewAssertionErrorWithWrappedErrf(err, "error during Size call"))
	}
	return temp.InternalType.Size()
}

// Identical is the internal implementation for T.Identical. See that comment
// for details.
func (t *InternalType) Identical(other *InternalType) bool {
	if t.Family != other.Family {
		return false
	}
	if t.Width != other.Width {
		return false
	}
	if t.Precision != other.Precision {
		return false
	}
	if t.TimePrecisionIsSet != other.TimePrecisionIsSet {
		return false
	}
	if t.IntervalDurationField != nil && other.IntervalDurationField != nil {
		if *t.IntervalDurationField != *other.IntervalDurationField {
			return false
		}
	} else if t.IntervalDurationField != nil {
		return false
	} else if other.IntervalDurationField != nil {
		return false
	}
	if t.GeoMetadata != nil && other.GeoMetadata != nil {
		if t.GeoMetadata.ShapeType != other.GeoMetadata.ShapeType {
			return false
		}
		if t.GeoMetadata.SRID != other.GeoMetadata.SRID {
			return false
		}
	} else if t.GeoMetadata != nil {
		return false
	} else if other.GeoMetadata != nil {
		return false
	}
	if t.Locale != nil && other.Locale != nil {
		if !lex.LocaleNamesAreEqual(*t.Locale, *other.Locale) {
			return false
		}
	} else if t.Locale != nil {
		return false
	} else if other.Locale != nil {
		return false
	}
	if t.ArrayContents != nil && other.ArrayContents != nil {
		if !t.ArrayContents.Identical(other.ArrayContents) {
			return false
		}
	} else if t.ArrayContents != nil {
		return false
	} else if other.ArrayContents != nil {
		return false
	}
	if len(t.TupleContents) != len(other.TupleContents) {
		return false
	}
	for i := range t.TupleContents {
		if !t.TupleContents[i].Identical(other.TupleContents[i]) {
			return false
		}
	}
	if len(t.TupleLabels) != len(other.TupleLabels) {
		return false
	}
	for i := range t.TupleLabels {
		if t.TupleLabels[i] != other.TupleLabels[i] {
			return false
		}
	}
	if t.UDTMetadata != nil && other.UDTMetadata != nil {
		if t.UDTMetadata.ArrayTypeOID != other.UDTMetadata.ArrayTypeOID {
			return false
		}
	} else if t.UDTMetadata != nil {
		return false
	} else if other.UDTMetadata != nil {
		return false
	}
	return t.Oid == other.Oid
}

// Unmarshal deserializes a type from the given byte representation using gogo
// protobuf serialization rules. It is backwards-compatible with formats used
// by older versions of CRDB.
//
//	var t T
//	err := protoutil.Unmarshal(data, &t)
//
// Unmarshal is part of the protoutil.Message interface.
func (t *T) Unmarshal(data []byte) error {
	// Unmarshal the internal type, and then perform an upgrade step to convert
	// to the latest format.
	err := protoutil.Unmarshal(data, &t.InternalType)
	if err != nil {
		return err
	}
	return t.upgradeType()
}

// upgradeType assumes its input was just unmarshaled from bytes that may have
// been serialized by any previous version of CRDB. It upgrades the object
// according to the requirements of the latest version by remapping fields and
// setting required values. This is necessary to preserve backwards-
// compatibility with older formats (e.g. restoring database from old backup).
func (t *T) upgradeType() error {
	switch t.Family() {
	case IntFamily:
		// Check VisibleType field that was populated in previous versions.
		switch t.InternalType.VisibleType {
		case visibleSMALLINT:
			t.InternalType.Width = 16
			t.InternalType.Oid = oid.T_int2
		case visibleINTEGER:
			t.InternalType.Width = 32
			t.InternalType.Oid = oid.T_int4
		case visibleBIGINT:
			t.InternalType.Width = 64
			t.InternalType.Oid = oid.T_int8
		case visibleBIT, visibleNONE:
			// Pre-2.1 BIT was using IntFamily with arbitrary widths. Clamp them
			// to fixed/known widths. See #34161.
			switch t.Width() {
			case 16:
				t.InternalType.Oid = oid.T_int2
			case 32:
				t.InternalType.Oid = oid.T_int4
			default:
				// Assume INT8 if width is 0 or not valid.
				t.InternalType.Oid = oid.T_int8
				t.InternalType.Width = 64
			}
		default:
			return errors.AssertionFailedf("unexpected visible type: %d", t.InternalType.VisibleType)
		}

	case FloatFamily:
		// Map visible REAL type to 32-bit width.
		switch t.InternalType.VisibleType {
		case visibleREAL:
			t.InternalType.Oid = oid.T_float4
			t.InternalType.Width = 32
		case visibleDOUBLE:
			t.InternalType.Oid = oid.T_float8
			t.InternalType.Width = 64
		case visibleNONE:
			switch t.Width() {
			case 32:
				t.InternalType.Oid = oid.T_float4
			case 64:
				t.InternalType.Oid = oid.T_float8
			default:
				// Pre-2.1 (before Width) there were 3 cases:
				// - VisibleType = DOUBLE PRECISION, Width = 0 -> now clearly FLOAT8
				// - VisibleType = NONE, Width = 0 -> now clearly FLOAT8
				// - VisibleType = NONE, Precision > 0 -> we need to derive the width.
				if t.Precision() >= 1 && t.Precision() <= 24 {
					t.InternalType.Oid = oid.T_float4
					t.InternalType.Width = 32
				} else {
					t.InternalType.Oid = oid.T_float8
					t.InternalType.Width = 64
				}
			}
		default:
			return errors.AssertionFailedf("unexpected visible type: %d", t.InternalType.VisibleType)
		}

		// Precision should always be set to 0 going forward.
		t.InternalType.Precision = 0

	case TimestampFamily, TimestampTZFamily, TimeFamily, TimeTZFamily:
		// Some bad/experimental versions of master had precision stored as `-1`.
		// This represented a default - so upgrade this to 0 with TimePrecisionIsSet = false.
		if t.InternalType.Precision == -1 {
			t.InternalType.Precision = 0
			t.InternalType.TimePrecisionIsSet = false
		}
		// Going forwards after 19.2, we want `TimePrecisionIsSet` to be explicitly set
		// if Precision is > 0.
		if t.InternalType.Precision > 0 {
			t.InternalType.TimePrecisionIsSet = true
		}
	case IntervalFamily:
		// Fill in the IntervalDurationField here.
		if t.InternalType.IntervalDurationField == nil {
			t.InternalType.IntervalDurationField = &IntervalDurationField{}
		}
		// Going forwards after 19.2, we want `TimePrecisionIsSet` to be explicitly set
		// if Precision is > 0.
		if t.InternalType.Precision > 0 {
			t.InternalType.TimePrecisionIsSet = true
		}
	case StringFamily, CollatedStringFamily:
		// Map string-related visible types to corresponding Oid values.
		switch t.InternalType.VisibleType {
		case visibleVARCHAR:
			t.InternalType.Oid = oid.T_varchar
		case visibleCHAR:
			t.InternalType.Oid = oid.T_bpchar
		case visibleQCHAR:
			t.InternalType.Oid = oid.T_char
		case visibleNONE:
			t.InternalType.Oid = oid.T_text
		default:
			return errors.AssertionFailedf("unexpected visible type: %d", t.InternalType.VisibleType)
		}
		if t.InternalType.Family == StringFamily {
			if t.InternalType.Locale != nil && len(*t.InternalType.Locale) != 0 {
				return errors.AssertionFailedf(
					"STRING type should not have locale: %s", *t.InternalType.Locale)
			}
		}

	case BitFamily:
		// Map visible VARBIT type to T_varbit OID value.
		switch t.InternalType.VisibleType {
		case visibleVARBIT:
			t.InternalType.Oid = oid.T_varbit
		case visibleNONE:
			t.InternalType.Oid = oid.T_bit
		default:
			return errors.AssertionFailedf("unexpected visible type: %d", t.InternalType.VisibleType)
		}

	case ArrayFamily:
		if t.ArrayContents() == nil {
			// This array type was serialized by a previous version of CRDB,
			// so construct the array contents from scratch.
			arrayContents := *t
			arrayContents.InternalType.Family = *t.InternalType.ArrayElemType
			arrayContents.InternalType.ArrayDimensions = nil
			arrayContents.InternalType.ArrayElemType = nil
			if err := arrayContents.upgradeType(); err != nil {
				return err
			}
			t.InternalType.ArrayContents = &arrayContents
			t.InternalType.Oid = CalcArrayOid(t.ArrayContents())
		}

		// Marshaling/unmarshaling nested arrays is not yet supported.
		if t.ArrayContents().Family() == ArrayFamily {
			return errors.AssertionFailedf("nested array should never be unmarshaled")
		}

		// Zero out fields that may have been used to store information about
		// the array element type, or which are no longer in use.
		t.InternalType.Width = 0
		t.InternalType.Precision = 0
		t.InternalType.Locale = nil
		t.InternalType.VisibleType = 0
		t.InternalType.ArrayElemType = nil
		t.InternalType.ArrayDimensions = nil

	case int2vector:
		t.InternalType.Family = ArrayFamily
		t.InternalType.Width = 0
		t.InternalType.Oid = oid.T_int2vector
		t.InternalType.ArrayContents = Int2

	case oidvector:
		t.InternalType.Family = ArrayFamily
		t.InternalType.Oid = oid.T_oidvector
		t.InternalType.ArrayContents = Oid

	case name:
		if t.InternalType.Locale != nil {
			t.InternalType.Family = CollatedStringFamily
		} else {
			t.InternalType.Family = StringFamily
		}
		t.InternalType.Oid = oid.T_name
		if t.Width() != 0 {
			return errors.AssertionFailedf("name type cannot have non-zero width: %d", t.Width())
		}
	}

	if t.InternalType.Oid == 0 {
		t.InternalType.Oid = familyToOid[t.Family()]
	}

	// Clear the deprecated visible types, since they are now handled by the
	// Width or Oid fields.
	t.InternalType.VisibleType = 0

	// If locale is not set, always set it to the empty string, in order to avoid
	// bothersome deref errors when the Locale method is called.
	if t.InternalType.Locale == nil {
		t.InternalType.Locale = &emptyLocale
	}

	return nil
}

// Marshal serializes a type into a byte representation using gogo protobuf
// serialization rules. It returns the resulting bytes as a slice. The bytes
// are serialized in a format that is backwards-compatible with the previous
// version of CRDB so that clusters can run in mixed version mode during
// upgrade.
//
//	bytes, err := protoutil.Marshal(&typ)
func (t *T) Marshal() (data []byte, err error) {
	// First downgrade to a struct that will be serialized in a backwards-
	// compatible bytes format.
	temp := *t
	if err := temp.downgradeType(); err != nil {
		return nil, err
	}
	return protoutil.Marshal(&temp.InternalType)
}

// MarshalToSizedBuffer is like Mashal, except that it deserializes to
// an existing byte slice with exactly enough remaining space for
// Size().
//
// Marshal is part of the protoutil.Message interface.
func (t *T) MarshalToSizedBuffer(data []byte) (int, error) {
	temp := *t
	if err := temp.downgradeType(); err != nil {
		return 0, err
	}
	return temp.InternalType.MarshalToSizedBuffer(data)
}

// MarshalTo behaves like Marshal, except that it deserializes to an existing
// byte slice and returns the number of bytes written to it. The slice must
// already have sufficient capacity. Callers can use the Size method to
// determine how much capacity needs to be allocated.
//
// Marshal is part of the protoutil.Message interface.
func (t *T) MarshalTo(data []byte) (int, error) {
	temp := *t
	if err := temp.downgradeType(); err != nil {
		return 0, err
	}
	return temp.InternalType.MarshalTo(data)
}

// of the latest CRDB version. It updates the fields so that they will be
// marshaled into a format that is compatible with the previous version of
// CRDB. This is necessary to preserve backwards-compatibility in mixed-version
// scenarios, such as during upgrade.
func (t *T) downgradeType() error {
	// Set Family and VisibleType for 19.1 backwards-compatibility.
	switch t.Family() {
	case BitFamily:
		if t.Oid() == oid.T_varbit {
			t.InternalType.VisibleType = visibleVARBIT
		}

	case FloatFamily:
		switch t.Width() {
		case 32:
			t.InternalType.VisibleType = visibleREAL
		}

	case StringFamily, CollatedStringFamily:
		switch t.Oid() {
		case oid.T_text:
			// Nothing to do.
		case oid.T_varchar:
			t.InternalType.VisibleType = visibleVARCHAR
		case oid.T_bpchar:
			t.InternalType.VisibleType = visibleCHAR
		case oid.T_char:
			t.InternalType.VisibleType = visibleQCHAR
		case oid.T_name:
			t.InternalType.Family = name
		default:
			return errors.AssertionFailedf("unexpected Oid: %d", t.Oid())
		}

	case ArrayFamily:
		// Marshaling/unmarshaling nested arrays is not yet supported.
		if t.ArrayContents().Family() == ArrayFamily {
			return errors.AssertionFailedf("nested array should never be marshaled")
		}

		// Downgrade to array representation used before 19.2, in which the array
		// type fields specified the width, locale, etc. of the element type.
		temp := *t.InternalType.ArrayContents
		if err := temp.downgradeType(); err != nil {
			return err
		}
		t.InternalType.Width = temp.InternalType.Width
		t.InternalType.Precision = temp.InternalType.Precision
		t.InternalType.Locale = temp.InternalType.Locale
		t.InternalType.VisibleType = temp.InternalType.VisibleType
		t.InternalType.ArrayElemType = &t.InternalType.ArrayContents.InternalType.Family

		switch t.Oid() {
		case oid.T_int2vector:
			t.InternalType.Family = int2vector
		case oid.T_oidvector:
			t.InternalType.Family = oidvector
		}
	}

	// Map empty locale to nil.
	if t.InternalType.Locale != nil && len(*t.InternalType.Locale) == 0 {
		t.InternalType.Locale = nil
	}

	return nil
}

// String returns the name of the type, similar to the Name method. However, it
// expands CollatedStringFamily, ArrayFamily, and TupleFamily types to be more
// descriptive.
//
// TODO(andyk): It'd be nice to have this return SqlString() method output,
// since that is more descriptive.
func (t *T) String() string {
	switch t.Family() {
	case CollatedStringFamily:
		if t.Locale() == "" {
			// Used in telemetry.
			return fmt.Sprintf("collated%s{*}", t.Name())
		}
		return fmt.Sprintf("collated%s{%s}", t.Name(), t.Locale())

	case ArrayFamily:
		switch t.Oid() {
		case oid.T_oidvector, oid.T_int2vector:
			return t.Name()
		}
		return t.ArrayContents().String() + "[]"

	case TupleFamily:
		var buf bytes.Buffer
		buf.WriteString("tuple")
		if len(t.TupleContents()) != 0 && !IsWildcardTupleType(t) {
			buf.WriteByte('{')
			for i, typ := range t.TupleContents() {
				if i != 0 {
					buf.WriteString(", ")
				}
				buf.WriteString(typ.String())
				if t.TupleLabels() != nil {
					buf.WriteString(" AS ")
					buf.WriteString(t.InternalType.TupleLabels[i])
				}
			}
			buf.WriteByte('}')
		}
		return buf.String()
	case IntervalFamily, TimestampFamily, TimestampTZFamily, TimeFamily, TimeTZFamily:
		if t.InternalType.Precision > 0 || t.InternalType.TimePrecisionIsSet {
			return fmt.Sprintf("%s(%d)", t.Name(), t.Precision())
		}
	}
	return t.Name()
}

// MarshalText is implemented here so that gogo/protobuf know how to text marshal
// protobuf struct directly/indirectly depends on types.T without panic.
func (t *T) MarshalText() (text []byte, err error) {
	var buf bytes.Buffer
	if err := proto.MarshalText(&buf, &t.InternalType); err != nil {
		return nil, err
	}
	return buf.Bytes(), nil
}

// DebugString returns a detailed dump of the type protobuf struct, suitable for
// debugging scenarios.
func (t *T) DebugString() string {
	if t.Family() == ArrayFamily && t.ArrayContents().UserDefined() {
		// In the case that this type is an array that contains a user defined
		// type, the introspection that protobuf performs to generate a string
		// representation will panic if the UserDefinedTypeMetadata field of the
		// type is populated. It seems to not understand that fields in the element
		// T could be not generated by proto, and panics trying to operate on the
		// TypeMeta field of the T. To get around this, we just deep copy the T and
		// zero out the type metadata to placate proto. See the following issue for
		// details: https://github.com/gogo/protobuf/issues/693.
		internalTypeCopy := protoutil.Clone(&t.InternalType).(*InternalType)
		internalTypeCopy.ArrayContents.TypeMeta = UserDefinedTypeMetadata{}
		return internalTypeCopy.String()
	}
	return t.InternalType.String()
}

// IsAmbiguous returns true if this type is in UnknownFamily or AnyFamily.
// Instances of ambiguous types can be NULL or be in one of several different
// type families. This is important for parameterized types to determine whether
// they are fully concrete or not.
func (t *T) IsAmbiguous() bool {
	switch t.Family() {
	case UnknownFamily, AnyFamily:
		return true
	case CollatedStringFamily:
		return t.Locale() == ""
	case TupleFamily:
		if len(t.TupleContents()) == 0 {
			return true
		}
		for i := range t.TupleContents() {
			if t.TupleContents()[i].IsAmbiguous() {
				return true
			}
		}
		return false
	case ArrayFamily:
		return t.ArrayContents().IsAmbiguous()
	case EnumFamily:
		return t.Oid() == oid.T_anyenum
	}
	return false
}

// IsNumeric returns true iff this type is an integer, float, or decimal.
func (t *T) IsNumeric() bool {
	switch t.Family() {
	case IntFamily, FloatFamily, DecimalFamily:
		return true
	default:
		return false
	}
}

// EnumGetIdxOfPhysical returns the index within the TypeMeta's slice of
// enum physical representations that matches the input byte slice.
func (t *T) EnumGetIdxOfPhysical(phys []byte) (int, error) {
	t.ensureHydratedEnum()
	// TODO (rohany): We can either use a map or just binary search here
	//  since the physical representations are sorted.
	reps := t.TypeMeta.EnumData.PhysicalRepresentations
	for i := range reps {
		if bytes.Equal(phys, reps[i]) {
			return i, nil
		}
	}
	err := errors.Newf(
		"could not find %v in enum %q representation %s %s",
		phys,
		t.TypeMeta.Name.FQName(),
		t.TypeMeta.EnumData.debugString(),
		debug.Stack(),
	)
	return 0, err
}

// EnumGetIdxOfLogical returns the index within the TypeMeta's slice of
// enum logical representations that matches the input string.
func (t *T) EnumGetIdxOfLogical(logical string) (int, error) {
	t.ensureHydratedEnum()
	reps := t.TypeMeta.EnumData.LogicalRepresentations
	for i := range reps {
		if reps[i] == logical {
			// If this enum member is read only, we cannot construct it from the
			// logical representation. This is to ensure that it will not be
			// written until all nodes in the cluster are able to decode the
			// physical representation.
			if t.TypeMeta.EnumData.IsMemberReadOnly[i] {
				return 0, errors.Newf("enum value %q is not yet public", logical)
			}
			return i, nil
		}
	}
	return 0, pgerror.Newf(
		pgcode.InvalidTextRepresentation, "invalid input value for enum %s: %q", t, logical)
}

func (t *T) ensureHydratedEnum() {
	if t.TypeMeta.EnumData == nil {
		panic(errors.AssertionFailedf("use of enum metadata before hydration as an enum: %v %p", t, t))
	}
}

// IsStringType returns true iff the given type is String or a collated string
// type.
func IsStringType(t *T) bool {
	switch t.Family() {
	case StringFamily, CollatedStringFamily:
		return true
	default:
		return false
	}
}

// IsValidArrayElementType returns true if the given type can be used as the
// element type of an ArrayFamily-typed column. If the valid return is false,
// the issue number should be included in the error report to inform the user.
func IsValidArrayElementType(t *T) (valid bool, issueNum int) {
	switch t.Family() {
	case TSQueryFamily:
		return false, 90886
	case TSVectorFamily:
		return false, 90886
	default:
		return true, 0
	}
}

// CheckArrayElementType ensures that the given type can be used as the element
// type of an ArrayFamily-typed column. If not, it returns an error.
func CheckArrayElementType(t *T) error {
	if ok, issueNum := IsValidArrayElementType(t); !ok {
		return unimplemented.NewWithIssueDetailf(issueNum, t.String(),
			"arrays of %s not allowed", t)
	}
	return nil
}

// IsDateTimeType returns true if the given type is a date or time-related type.
func IsDateTimeType(t *T) bool {
	switch t.Family() {
	case DateFamily:
		return true
	case TimeFamily:
		return true
	case TimeTZFamily:
		return true
	case TimestampFamily:
		return true
	case TimestampTZFamily:
		return true
	case IntervalFamily:
		return true
	default:
		return false
	}
}

// IsAdditiveType returns true if the given type supports addition and
// subtraction.
func IsAdditiveType(t *T) bool {
	switch t.Family() {
	case IntFamily:
		return true
	case FloatFamily:
		return true
	case DecimalFamily:
		return true
	default:
		return IsDateTimeType(t)
	}
}

// IsWildcardTupleType returns true if this is the wildcard AnyTuple type. The
// wildcard type matches a tuple type having any number of fields (including 0).
func IsWildcardTupleType(t *T) bool {
	return len(t.TupleContents()) == 1 && t.TupleContents()[0].Family() == AnyFamily
}

// IsRecordType returns true if this is a RECORD type. This should only be used
// when processing UDFs. A record differs from AnyTuple in that the tuple
// contents may contain types other than Any.
func IsRecordType(typ *T) bool {
	return typ.Family() == TupleFamily && typ.Oid() == oid.T_record
}

// collatedStringTypeSQL returns the string representation of a COLLATEDSTRING
// or []COLLATEDSTRING type. This is tricky in the case of an array of collated
// string, since brackets must precede the COLLATE identifier:
//
//	STRING COLLATE EN
//	VARCHAR(20)[] COLLATE DE
func (t *T) collatedStringTypeSQL(isArray bool) string {
	var buf bytes.Buffer
	buf.WriteString(t.stringTypeSQL())
	if isArray {
		buf.WriteString("[] COLLATE ")
	} else {
		buf.WriteString(" COLLATE ")
	}
	lex.EncodeLocaleName(&buf, t.Locale())
	return buf.String()
}

// stringTypeSQL returns the visible type name plus any width specifier for the
// STRING/COLLATEDSTRING type.
func (t *T) stringTypeSQL() string {
	typName := "STRING"
	switch t.Oid() {
	case oid.T_varchar:
		typName = "VARCHAR"
	case oid.T_bpchar:
		typName = "CHAR"
	case oid.T_char:
		// Yes, that's the name. The ways of PostgreSQL are inscrutable.
		typName = `"char"`
	case oid.T_name:
		typName = "NAME"
	}

	// In general, if there is a specified width we want to print it next to the
	// type. However, in the specific case of CHAR and "char", the default is 1
	// and the width should be omitted in that case.
	if t.Width() > 0 {
		o := t.Oid()
		if t.Width() != 1 || (o != oid.T_bpchar && o != oid.T_char) {
			typName = fmt.Sprintf("%s(%d)", typName, t.Width())
		}
	}

	return typName
}

// IsHydrated returns true if this is a user-defined type and the TypeMeta
// is hydrated.
func (t *T) IsHydrated() bool {
	return t.UserDefined() && t.TypeMeta != (UserDefinedTypeMetadata{})
}

var typNameLiterals map[string]*T

func init() {
	typNameLiterals = make(map[string]*T)
	for o, t := range OidToType {
		name, ok := oidext.TypeName(o)
		if !ok {
			panic(errors.AssertionFailedf("oid %d has no type name", o))
		}
		name = strings.ToLower(name)
		if _, ok := typNameLiterals[name]; !ok {
			typNameLiterals[name] = t
		}
	}
	for name, t := range unreservedTypeTokens {
		if _, ok := typNameLiterals[name]; !ok {
			typNameLiterals[name] = t
		}
	}
}

// TypeForNonKeywordTypeName returns the column type for the string name of a
// type, if one exists. The third return value indicates:
//
//	 0 if no error or the type is not known in postgres.
//	 -1 if the type is known in postgres.
//	>0 for a github issue number.
func TypeForNonKeywordTypeName(name string) (*T, bool, int) {
	t, ok := typNameLiterals[name]
	if ok {
		return t, ok, 0
	}
	return nil, false, postgresPredefinedTypeIssues[name]
}

// The SERIAL types are pseudo-types that are only used during parsing. After
// that, they should behave identically to INT columns. They are declared
// as INT types, but using different instances than types.Int, types.Int2, etc.
// so that they can be compared by pointer to differentiate them from the
// singleton INT types. While the usual requirement is that == is never used to
// compare types, this is one case where it's allowed.
var (
	Serial2Type = *Int2
	Serial4Type = *Int4
	Serial8Type = *Int
)

// IsSerialType returns whether or not the input type is a SERIAL type.
// This function should only be used during parsing.
func IsSerialType(typ *T) bool {
	// This is a special case where == is used to compare types, since the SERIAL
	// types are pseudo-types.
	return typ == &Serial2Type || typ == &Serial4Type || typ == &Serial8Type
}

// unreservedTypeTokens contain type alias that we resolve during parsing.
// Instead of adding a new token to the parser, add the type here.
var unreservedTypeTokens = map[string]*T{
	"blob":       Bytes,
	"bool":       Bool,
	"bytea":      Bytes,
	"bytes":      Bytes,
	"date":       Date,
	"float4":     Float,
	"float8":     Float,
	"inet":       INet,
	"int2":       Int2,
	"int4":       Int4,
	"int8":       Int,
	"int64":      Int,
	"int2vector": Int2Vector,
	// NOTE(sql-exp): Change the line below to Json if we support the JSON type.
	"json":      Jsonb,
	"jsonb":     Jsonb,
	"name":      Name,
	"oid":       Oid,
	"oidvector": OidVector,
	// Postgres OID pseudo-types. See https://www.postgresql.org/docs/9.4/static/datatype-oid.html.
	"regclass":     RegClass,
	"regnamespace": RegNamespace,
	"regproc":      RegProc,
	"regprocedure": RegProcedure,
	"regrole":      RegRole,
	"regtype":      RegType,

	"serial2":     &Serial2Type,
	"serial4":     &Serial4Type,
	"serial8":     &Serial8Type,
	"smallserial": &Serial2Type,
	"bigserial":   &Serial8Type,

	"string": String,
	"uuid":   Uuid,
}

// The following map must include all types predefined in PostgreSQL
// that are also not yet defined in CockroachDB and link them to
// github issues. It is also possible, but not necessary, to include
// PostgreSQL types that are already implemented in CockroachDB.
var postgresPredefinedTypeIssues = map[string]int{
	"box":           21286,
	"cidr":          18846,
	"circle":        21286,
	"jsonpath":      22513,
	"line":          21286,
	"lseg":          21286,
	"macaddr":       45813,
	"macaddr8":      45813,
	"money":         41578,
	"path":          21286,
	"pg_lsn":        -1,
	"txid_snapshot": -1,
	"xml":           43355,
}

// SQLString outputs the GeoMetadata in a SQL-compatible string.
func (m *GeoMetadata) SQLString() string {
	// If SRID is available, display both shape and SRID.
	// If shape is available but not SRID, just display shape.
	if m.SRID != 0 {
		shapeName := strings.ToLower(m.ShapeType.String())
		if m.ShapeType == geopb.ShapeType_Unset {
			shapeName = "geometry"
		}
		return fmt.Sprintf("(%s,%d)", shapeName, m.SRID)
	} else if m.ShapeType != geopb.ShapeType_Unset {
		return fmt.Sprintf("(%s)", m.ShapeType)
	}
	return ""
}

// Delimiter selects the correct delimiter rune based on the datum type specified.
func (t *T) Delimiter() string {
	switch t.Family() {
	case Geometry.Family(), Geography.Family():
		return ":"
	default:
		return ","
	}
}