importccl: Preserve '\r\n' during CSV import

See cockroachdb#25344.

It appears this is being caused by the behaviour of Golang's
encoding/csv library, which folds \r\n into \n when reading. This was
fixed in golang/go#21201 but then reverted golang/go#22746. It appears
based on that second issue that Go is unlikely to change that behavior.

Check in the stdlib `encoding/csv` into `pkg/util` with
golang/go#22746 reverted.

Release note:
`\r\n` characters in CSV files were silently converted into `\n`. This
causes imported data to be different. This is now fixed.

pkg/acceptance/decommission_test.go

@@ -16,7 +16,6 @@ package acceptance
 
 import (
 	"context"
-	"encoding/csv"
 	"reflect"
 	"regexp"
 	"strconv"
@@ -31,6 +30,7 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/server/serverpb"
 	"github.com/cockroachdb/cockroach/pkg/sql"
 	"github.com/cockroachdb/cockroach/pkg/testutils/sqlutils"
+	"github.com/cockroachdb/cockroach/pkg/util/encoding/csv"
 	"github.com/cockroachdb/cockroach/pkg/util/httputil"
 	"github.com/cockroachdb/cockroach/pkg/util/log"
 	"github.com/cockroachdb/cockroach/pkg/util/retry"

pkg/ccl/importccl/csv.go

@@ -11,7 +11,6 @@ package importccl
 import (
 	"bytes"
 	"context"
-	"encoding/csv"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -45,6 +44,7 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/sqlbase"
 	"github.com/cockroachdb/cockroach/pkg/storage/engine"
 	"github.com/cockroachdb/cockroach/pkg/util"
+	"github.com/cockroachdb/cockroach/pkg/util/encoding/csv"
 	"github.com/cockroachdb/cockroach/pkg/util/hlc"
 	"github.com/cockroachdb/cockroach/pkg/util/humanizeutil"
 	"github.com/cockroachdb/cockroach/pkg/util/log"

pkg/ccl/importccl/csv_test.go

@@ -82,6 +82,14 @@ func TestLoadCSVBytes(t *testing.T) {
 			csv:    `\x0`,
 			err:    "odd length hex string",
 		},
+		{
+			name:   "new line characters",
+			create: `t text`,
+			csv:    "\"hello\r\nworld\"\n\"friend\nfoe\"\n\"mr\rmrs\"",
+			query: map[string][][]string{
+				`SELECT t from d.t`: {{"hello\r\nworld"}, {"friend\nfoe"}, {"mr\rmrs"}},
+			},
+		},
 	}
 
 	var csvString string

pkg/cli/format_table.go

@@ -16,7 +16,6 @@ package cli
 
 import (
 	"bytes"
-	"encoding/csv"
 	"fmt"
 	"html"
 	"io"
@@ -27,6 +26,7 @@ import (
 
 	"github.com/cockroachdb/cockroach/pkg/sql/sem/tree"
 	"github.com/cockroachdb/cockroach/pkg/util"
+	"github.com/cockroachdb/cockroach/pkg/util/encoding/csv"
 	"github.com/olekukonko/tablewriter"
 	"github.com/pkg/errors"
 )

pkg/testutils/lint/testdata/errcheck_excludes.txt

@@ -1,3 +1,4 @@
+(*bufio.Writer).Flush
 (*database/sql.DB).Close
 (*database/sql.Rows).Close
 (*database/sql.Stmt).Close

pkg/util/encoding/csv/example_test.go

@@ -0,0 +1,140 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package csv_test
+
+import (
+	"context"
+	"encoding/csv"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+
+	"github.com/cockroachdb/cockroach/pkg/util/log"
+)
+
+func ExampleReader() {
+	ctx := context.Background()
+	in := `first_name,last_name,username
+"Rob","Pike",rob
+Ken,Thompson,ken
+"Robert","Griesemer","gri"
+`
+	r := csv.NewReader(strings.NewReader(in))
+
+	for {
+		record, err := r.Read()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			log.Fatal(ctx, err)
+		}
+
+		fmt.Println(record)
+	}
+	// Output:
+	// [first_name last_name username]
+	// [Rob Pike rob]
+	// [Ken Thompson ken]
+	// [Robert Griesemer gri]
+}
+
+// This example shows how csv.Reader can be configured to handle other
+// types of CSV files.
+func ExampleReader_options() {
+	ctx := context.Background()
+	in := `first_name;last_name;username
+"Rob";"Pike";rob
+# lines beginning with a # character are ignored
+Ken;Thompson;ken
+"Robert";"Griesemer";"gri"
+`
+	r := csv.NewReader(strings.NewReader(in))
+	r.Comma = ';'
+	r.Comment = '#'
+
+	records, err := r.ReadAll()
+	if err != nil {
+		log.Fatal(ctx, err)
+	}
+
+	fmt.Print(records)
+	// Output:
+	// [[first_name last_name username] [Rob Pike rob] [Ken Thompson ken] [Robert Griesemer gri]]
+}
+
+func ExampleReader_ReadAll() {
+	ctx := context.Background()
+	in := `first_name,last_name,username
+"Rob","Pike",rob
+Ken,Thompson,ken
+"Robert","Griesemer","gri"
+`
+	r := csv.NewReader(strings.NewReader(in))
+
+	records, err := r.ReadAll()
+	if err != nil {
+		log.Fatal(ctx, err)
+	}
+
+	fmt.Print(records)
+	// Output:
+	// [[first_name last_name username] [Rob Pike rob] [Ken Thompson ken] [Robert Griesemer gri]]
+}
+
+func ExampleWriter() {
+	ctx := context.Background()
+	records := [][]string{
+		{"first_name", "last_name", "username"},
+		{"Rob", "Pike", "rob"},
+		{"Ken", "Thompson", "ken"},
+		{"Robert", "Griesemer", "gri"},
+	}
+
+	w := csv.NewWriter(os.Stdout)
+
+	for _, record := range records {
+		if err := w.Write(record); err != nil {
+			log.Fatalf(ctx, "error writing record to csv: %v\n", err)
+		}
+	}
+
+	// Write any buffered data to the underlying writer (standard output).
+	w.Flush()
+
+	if err := w.Error(); err != nil {
+		log.Fatal(ctx, err)
+	}
+	// Output:
+	// first_name,last_name,username
+	// Rob,Pike,rob
+	// Ken,Thompson,ken
+	// Robert,Griesemer,gri
+}
+
+func ExampleWriter_WriteAll() {
+	ctx := context.Background()
+	records := [][]string{
+		{"first_name", "last_name", "username"},
+		{"Rob", "Pike", "rob"},
+		{"Ken", "Thompson", "ken"},
+		{"Robert", "Griesemer", "gri"},
+	}
+
+	w := csv.NewWriter(os.Stdout)
+	if err := w.WriteAll(records); err != nil { // calls Flush internally
+		log.Fatalf(ctx, "error writing csv: %v\n", err)
+	}
+
+	if err := w.Error(); err != nil {
+		log.Fatalf(ctx, "error writing csv: %v\n", err)
+	}
+	// Output:
+	// first_name,last_name,username
+	// Rob,Pike,rob
+	// Ken,Thompson,ken
+	// Robert,Griesemer,gri
+}