text/template: use strings.Builder

Change-Id: I559986b5408d3967c58c9abc6e8f4b04b25496a6
Reviewed-on: https://go-review.googlesource.com/c/go/+/428280
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Run-TryBot: Ian Lance Taylor <iant@google.com>

3 files changed, 16 insertions, 17 deletions

diff --git a/src/text/template/exec_test.go b/src/text/template/exec_test.go
index 56566b920f..6bfae3d319 100644
--- a/src/text/template/exec_test.go
+++ b/src/text/template/exec_test.go
@@ -772,7 +772,7 @@ func mapOfThree() any {
 }
 
 func testExecute(execTests []execTest, template *Template, t *testing.T) {
-	b := new(bytes.Buffer)
+	b := new(strings.Builder)
 	funcs := FuncMap{
 		"add":         add,
 		"count":       count,
@@ -861,7 +861,7 @@ func TestDelims(t *testing.T) {
 		if err != nil {
 			t.Fatalf("delim %q text %q parse err %s", left, text, err)
 		}
-		var b = new(bytes.Buffer)
+		var b = new(strings.Builder)
 		err = tmpl.Execute(b, value)
 		if err != nil {
 			t.Fatalf("delim %q exec err %s", left, err)
@@ -1024,7 +1024,7 @@ func TestTree(t *testing.T) {
 	if err != nil {
 		t.Fatal("parse error:", err)
 	}
-	var b bytes.Buffer
+	var b strings.Builder
 	const expect = "[1[2[3[4]][5[6]]][7[8[9]][10[11]]]]"
 	// First by looking up the template.
 	err = tmpl.Lookup("tree").Execute(&b, tree)
@@ -1236,7 +1236,7 @@ var cmpTests = []cmpTest{
 }
 
 func TestComparison(t *testing.T) {
-	b := new(bytes.Buffer)
+	b := new(strings.Builder)
 	var cmpStruct = struct {
 		Uthree, Ufour    uint
 		NegOne, Three    int
@@ -1284,7 +1284,7 @@ func TestMissingMapKey(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	var b bytes.Buffer
+	var b strings.Builder
 	// By default, just get "<no value>"
 	err = tmpl.Execute(&b, data)
 	if err != nil {
@@ -1454,7 +1454,7 @@ func TestBlock(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	var buf bytes.Buffer
+	var buf strings.Builder
 	if err := tmpl.Execute(&buf, "hello"); err != nil {
 		t.Fatal(err)
 	}
@@ -1560,7 +1560,7 @@ func TestAddrOfIndex(t *testing.T) {
 	}
 	for _, text := range texts {
 		tmpl := Must(New("tmpl").Parse(text))
-		var buf bytes.Buffer
+		var buf strings.Builder
 		err := tmpl.Execute(&buf, reflect.ValueOf([]V{{1}}))
 		if err != nil {
 			t.Fatalf("%s: Execute: %v", text, err)
@@ -1616,7 +1616,7 @@ func TestInterfaceValues(t *testing.T) {
 
 	for _, tt := range tests {
 		tmpl := Must(New("tmpl").Parse(tt.text))
-		var buf bytes.Buffer
+		var buf strings.Builder
 		err := tmpl.Execute(&buf, map[string]any{
 			"PlusOne": func(n int) int {
 				return n + 1
@@ -1709,7 +1709,7 @@ func TestExecutePanicDuringCall(t *testing.T) {
 // Issue 31810. Check that a parenthesized first argument behaves properly.
 func TestIssue31810(t *testing.T) {
 	// A simple value with no arguments is fine.
-	var b bytes.Buffer
+	var b strings.Builder
 	const text = "{{ (.)  }}"
 	tmpl, err := New("").Parse(text)
 	if err != nil {
diff --git a/src/text/template/funcs.go b/src/text/template/funcs.go
index 42bb529e50..dbea6e705a 100644
--- a/src/text/template/funcs.go
+++ b/src/text/template/funcs.go
@@ -5,7 +5,6 @@
 package template
 
 import (
-	"bytes"
 	"errors"
 	"fmt"
 	"io"
@@ -642,7 +641,7 @@ func HTMLEscapeString(s string) string {
 	if !strings.ContainsAny(s, "'\"&<>\000") {
 		return s
 	}
-	var b bytes.Buffer
+	var b strings.Builder
 	HTMLEscape(&b, []byte(s))
 	return b.String()
 }
@@ -725,7 +724,7 @@ func JSEscapeString(s string) string {
 	if strings.IndexFunc(s, jsIsSpecial) < 0 {
 		return s
 	}
-	var b bytes.Buffer
+	var b strings.Builder
 	JSEscape(&b, []byte(s))
 	return b.String()
 }
diff --git a/src/text/template/multi_test.go b/src/text/template/multi_test.go
index 6b81ffe7ac..63cd3f74b2 100644
--- a/src/text/template/multi_test.go
+++ b/src/text/template/multi_test.go
@@ -7,9 +7,9 @@ package template
 // Tests for multiple-template parsing and execution.
 
 import (
-	"bytes"
 	"fmt"
 	"os"
+	"strings"
 	"testing"
 	"text/template/parse"
 )
@@ -242,7 +242,7 @@ func TestClone(t *testing.T) {
 		}
 	}
 	// Execute root.
-	var b bytes.Buffer
+	var b strings.Builder
 	err = root.ExecuteTemplate(&b, "a", 0)
 	if err != nil {
 		t.Fatal(err)
@@ -281,7 +281,7 @@ func TestAddParseTree(t *testing.T) {
 		t.Fatal(err)
 	}
 	// Execute.
-	var b bytes.Buffer
+	var b strings.Builder
 	err = added.ExecuteTemplate(&b, "a", 0)
 	if err != nil {
 		t.Fatal(err)
@@ -410,7 +410,7 @@ func TestEmptyTemplate(t *testing.T) {
 				t.Fatal(err)
 			}
 		}
-		buf := &bytes.Buffer{}
+		buf := &strings.Builder{}
 		if err := m.Execute(buf, c.in); err != nil {
 			t.Error(i, err)
 			continue
@@ -445,7 +445,7 @@ func TestIssue19294(t *testing.T) {
 				t.Fatal(err)
 			}
 		}
-		var buf bytes.Buffer
+		var buf strings.Builder
 		res.Execute(&buf, 0)
 		if buf.String() != "stylesheet" {
 			t.Fatalf("iteration %d: got %q; expected %q", i, buf.String(), "stylesheet")