tree: add FmtExport formatting for array types

Part of work for cockroachdb#44322.

Fixes cockroachdb#33429.

Release note (enterprise change): This PR fixes a bug where
export/import could not round trip arrays correctly.

pkg/ccl/importccl/import_stmt_test.go

@@ -1553,6 +1553,19 @@ func TestImportCSVStmt(t *testing.T) {
 	})
 }
 
+func TestExportImportRoundTrip(t *testing.T) {
+	defer leaktest.AfterTest(t)()
+	ctx := context.Background()
+	baseDir := filepath.Join("testdata", "csv")
+	tc := testcluster.StartTestCluster(
+		t, 1, base.TestClusterArgs{ServerArgs: base.TestServerArgs{ExternalIODir: baseDir}})
+	defer tc.Stopper().Stop(ctx)
+	conn := tc.Conns[0]
+	sqlDB := sqlutils.MakeSQLRunner(conn)
+	sqlDB.Exec(t, `EXPORT INTO CSV 'nodelocal:///foo.csv' FROM SELECT ARRAY['a', 'b', 'c']`)
+	sqlDB.Exec(t, `IMPORT TABLE zc(x TEXT[]) CSV DATA ('nodelocal:///foo.csv/n1.0.csv')`)
+}
+
 // TODO(adityamaru): Tests still need to be added incrementally as
 // relevant IMPORT INTO logic is added. Some of them include:
 // -> FK and constraint violation

pkg/sql/sem/tree/format.go

@@ -159,7 +159,7 @@ const (
 	// FmtExport, if set, formats datums in a raw form suitable for
 	// EXPORT, e.g. suitable for output into a CSV file. The intended
 	// goal for this flag is to ensure values can be read back using the
-	// ParseDatumStringAs() / ParseStringas() functions (IMPORT).
+	// ParseDatumStringAs() / ParseStringAs() functions (IMPORT).
 	//
 	// We do not use FmtParsable for this purpose because FmtParsable
 	// intends to preserve all the information useful to CockroachDB

pkg/sql/sem/tree/parse_array.go

@@ -23,8 +23,8 @@ import (
 	"github.com/cockroachdb/errors"
 )
 
-var enclosingError = pgerror.Newf(pgcode.InvalidTextRepresentation, "array must be enclosed in { and }")
-var extraTextError = pgerror.Newf(pgcode.InvalidTextRepresentation, "extra text after closing right brace")
+var enclosingError = pgerror.Newf(pgcode.InvalidTextRepresentation, "array must be enclosed in ARRAY[ and ]")
+var extraTextError = pgerror.Newf(pgcode.InvalidTextRepresentation, "extra text after closing right bracket")
 var nestedArraysNotSupportedError = unimplemented.NewWithIssueDetail(32552, "strcast", "nested arrays not supported")
 var malformedError = pgerror.Newf(pgcode.InvalidTextRepresentation, "malformed array")
 
@@ -33,11 +33,11 @@ var isQuoteChar = func(ch byte) bool {
 }
 
 var isControlChar = func(ch byte) bool {
-	return ch == '{' || ch == '}' || ch == ',' || ch == '"'
+	return ch == '[' || ch == ']' || ch == ',' || ch == '"'
 }
 
 var isElementChar = func(r rune) bool {
-	return r != '{' && r != '}' && r != ','
+	return r != '[' && r != ']' && r != ','
 }
 
 // gobbleString advances the parser for the remainder of the current string
@@ -148,7 +148,7 @@ func (p *parseState) parseElement() error {
 }
 
 // ParseDArrayFromString parses the string-form of constructing arrays, handling
-// cases such as `'{1,2,3}'::INT[]`. The input type t is the type of the
+// cases such as `ARRAY[1, 2, 3]`. The input type t is the type of the
 // parameter of the array to parse.
 func ParseDArrayFromString(ctx ParseTimeContext, s string, t *types.T) (*DArray, error) {
 	ret, err := doParseDArrayFromString(ctx, s, t)
@@ -158,7 +158,7 @@ func ParseDArrayFromString(ctx ParseTimeContext, s string, t *types.T) (*DArray,
 	return ret, nil
 }
 
-// doParseDArraryFromString does most of the work of ParseDArrayFromString,
+// doParseDArrayFromString does most of the work of ParseDArrayFromString,
 // except the error it returns isn't prettified as a parsing error.
 func doParseDArrayFromString(ctx ParseTimeContext, s string, t *types.T) (*DArray, error) {
 	parser := parseState{
@@ -169,12 +169,19 @@ func doParseDArrayFromString(ctx ParseTimeContext, s string, t *types.T) (*DArra
 	}
 
 	parser.eatWhitespace()
-	if parser.peek() != '{' {
+	out, err := parser.gobbleString(isControlChar)
+	if err != nil {
+		return nil, err
+	}
+	if out != "ARRAY" {
+		return nil, enclosingError
+	}
+	if parser.peek() != '[' {
 		return nil, enclosingError
 	}
 	parser.advance()
 	parser.eatWhitespace()
-	if parser.peek() != '}' {
+	if parser.peek() != ']' {
 		if err := parser.parseElement(); err != nil {
 			return nil, err
 		}
@@ -191,14 +198,13 @@ func doParseDArrayFromString(ctx ParseTimeContext, s string, t *types.T) (*DArra
 	if parser.eof() {
 		return nil, enclosingError
 	}
-	if parser.peek() != '}' {
+	if parser.peek() != ']' {
 		return nil, malformedError
 	}
 	parser.advance()
 	parser.eatWhitespace()
 	if !parser.eof() {
 		return nil, extraTextError
 	}
-
 	return parser.result, nil
 }

pkg/sql/sem/tree/parse_string_test.go

@@ -30,6 +30,17 @@ func TestParseDatumStringAs(t *testing.T) {
 			"true",
 			"false",
 		},
+		types.IntArray: {
+			"ARRAY[1]",
+			"ARRAY[1,2,3]",
+		},
+		types.StringArray: {
+			`ARRAY['hello','world']`,
+			`ARRAY['cockroach','database']`,
+		},
+		types.MakeArray(types.Decimal): {
+			`ARRAY[1.021,5.20503]`,
+		},
 		types.Bytes: {
 			`\x`,
 			`\x00`,