Fix Go template script escaping

Fixes #6695

tpl/internal/go_templates/texttemplate/parse/node.go

@@ -7,7 +7,6 @@
 package parse
 
 import (
-	"bytes"
 	"fmt"
 	"strconv"
 	"strings"
@@ -29,6 +28,8 @@ type Node interface {
 	// tree returns the containing *Tree.
 	// It is unexported so all implementations of Node are in this package.
 	tree() *Tree
+	// writeTo writes the String output to the builder.
+	writeTo(*strings.Builder)
 }
 
 // NodeType identifies the type of a parse tree node.
@@ -94,11 +95,15 @@ func (l *ListNode) tree() *Tree {
 }
 
 func (l *ListNode) String() string {
-	b := new(bytes.Buffer)
+	var sb strings.Builder
+	l.writeTo(&sb)
+	return sb.String()
+}
+
+func (l *ListNode) writeTo(sb *strings.Builder) {
 	for _, n := range l.Nodes {
-		fmt.Fprint(b, n)
+		n.writeTo(sb)
 	}
-	return b.String()
 }
 
 func (l *ListNode) CopyList() *ListNode {
@@ -132,6 +137,10 @@ func (t *TextNode) String() string {
 	return fmt.Sprintf(textFormat, t.Text)
 }
 
+func (t *TextNode) writeTo(sb *strings.Builder) {
+	sb.WriteString(t.String())
+}
+
 func (t *TextNode) tree() *Tree {
 	return t.tr
 }
@@ -160,23 +169,27 @@ func (p *PipeNode) append(command *CommandNode) {
 }
 
 func (p *PipeNode) String() string {
-	s := ""
+	var sb strings.Builder
+	p.writeTo(&sb)
+	return sb.String()
+}
+
+func (p *PipeNode) writeTo(sb *strings.Builder) {
 	if len(p.Decl) > 0 {
 		for i, v := range p.Decl {
 			if i > 0 {
-				s += ", "
+				sb.WriteString(", ")
 			}
-			s += v.String()
+			v.writeTo(sb)
 		}
-		s += " := "
+		sb.WriteString(" := ")
 	}
 	for i, c := range p.Cmds {
 		if i > 0 {
-			s += " | "
+			sb.WriteString(" | ")
 		}
-		s += c.String()
+		c.writeTo(sb)
 	}
-	return s
 }
 
 func (p *PipeNode) tree() *Tree {
@@ -187,9 +200,9 @@ func (p *PipeNode) CopyPipe() *PipeNode {
 	if p == nil {
 		return p
 	}
-	var vars []*VariableNode
-	for _, d := range p.Decl {
-		vars = append(vars, d.Copy().(*VariableNode))
+	vars := make([]*VariableNode, len(p.Decl))
+	for i, d := range p.Decl {
+		vars[i] = d.Copy().(*VariableNode)
 	}
 	n := p.tr.newPipeline(p.Pos, p.Line, vars)
 	n.IsAssign = p.IsAssign
@@ -219,8 +232,15 @@ func (t *Tree) newAction(pos Pos, line int, pipe *PipeNode) *ActionNode {
 }
 
 func (a *ActionNode) String() string {
-	return fmt.Sprintf("{{%s}}", a.Pipe)
+	var sb strings.Builder
+	a.writeTo(&sb)
+	return sb.String()
+}
 
+func (a *ActionNode) writeTo(sb *strings.Builder) {
+	sb.WriteString("{{")
+	a.Pipe.writeTo(sb)
+	sb.WriteString("}}")
 }
 
 func (a *ActionNode) tree() *Tree {
@@ -249,18 +269,24 @@ func (c *CommandNode) append(arg Node) {
 }
 
 func (c *CommandNode) String() string {
-	s := ""
+	var sb strings.Builder
+	c.writeTo(&sb)
+	return sb.String()
+}
+
+func (c *CommandNode) writeTo(sb *strings.Builder) {
 	for i, arg := range c.Args {
 		if i > 0 {
-			s += " "
+			sb.WriteByte(' ')
 		}
 		if arg, ok := arg.(*PipeNode); ok {
-			s += "(" + arg.String() + ")"
+			sb.WriteByte('(')
+			arg.writeTo(sb)
+			sb.WriteByte(')')
 			continue
 		}
-		s += arg.String()
+		arg.writeTo(sb)
 	}
-	return s
 }
 
 func (c *CommandNode) tree() *Tree {
@@ -311,6 +337,10 @@ func (i *IdentifierNode) String() string {
 	return i.Ident
 }
 
+func (i *IdentifierNode) writeTo(sb *strings.Builder) {
+	sb.WriteString(i.String())
+}
+
 func (i *IdentifierNode) tree() *Tree {
 	return i.tr
 }
@@ -333,14 +363,18 @@ func (t *Tree) newVariable(pos Pos, ident string) *VariableNode {
 }
 
 func (v *VariableNode) String() string {
-	s := ""
+	var sb strings.Builder
+	v.writeTo(&sb)
+	return sb.String()
+}
+
+func (v *VariableNode) writeTo(sb *strings.Builder) {
 	for i, id := range v.Ident {
 		if i > 0 {
-			s += "."
+			sb.WriteByte('.')
 		}
-		s += id
+		sb.WriteString(id)
 	}
-	return s
 }
 
 func (v *VariableNode) tree() *Tree {
@@ -373,6 +407,10 @@ func (d *DotNode) String() string {
 	return "."
 }
 
+func (d *DotNode) writeTo(sb *strings.Builder) {
+	sb.WriteString(d.String())
+}
+
 func (d *DotNode) tree() *Tree {
 	return d.tr
 }
@@ -403,6 +441,10 @@ func (n *NilNode) String() string {
 	return "nil"
 }
 
+func (n *NilNode) writeTo(sb *strings.Builder) {
+	sb.WriteString(n.String())
+}
+
 func (n *NilNode) tree() *Tree {
 	return n.tr
 }
@@ -426,11 +468,16 @@ func (t *Tree) newField(pos Pos, ident string) *FieldNode {
 }
 
 func (f *FieldNode) String() string {
-	s := ""
+	var sb strings.Builder
+	f.writeTo(&sb)
+	return sb.String()
+}
+
+func (f *FieldNode) writeTo(sb *strings.Builder) {
 	for _, id := range f.Ident {
-		s += "." + id
+		sb.WriteByte('.')
+		sb.WriteString(id)
 	}
-	return s
 }
 
 func (f *FieldNode) tree() *Tree {
@@ -469,14 +516,23 @@ func (c *ChainNode) Add(field string) {
 }
 
 func (c *ChainNode) String() string {
-	s := c.Node.String()
+	var sb strings.Builder
+	c.writeTo(&sb)
+	return sb.String()
+}
+
+func (c *ChainNode) writeTo(sb *strings.Builder) {
 	if _, ok := c.Node.(*PipeNode); ok {
-		s = "(" + s + ")"
+		sb.WriteByte('(')
+		c.Node.writeTo(sb)
+		sb.WriteByte(')')
+	} else {
+		c.Node.writeTo(sb)
 	}
 	for _, field := range c.Field {
-		s += "." + field
+		sb.WriteByte('.')
+		sb.WriteString(field)
 	}
-	return s
 }
 
 func (c *ChainNode) tree() *Tree {
@@ -506,6 +562,10 @@ func (b *BoolNode) String() string {
 	return "false"
 }
 
+func (b *BoolNode) writeTo(sb *strings.Builder) {
+	sb.WriteString(b.String())
+}
+
 func (b *BoolNode) tree() *Tree {
 	return b.tr
 }
@@ -639,6 +699,10 @@ func (n *NumberNode) String() string {
 	return n.Text
 }
 
+func (n *NumberNode) writeTo(sb *strings.Builder) {
+	sb.WriteString(n.String())
+}
+
 func (n *NumberNode) tree() *Tree {
 	return n.tr
 }
@@ -666,6 +730,10 @@ func (s *StringNode) String() string {
 	return s.Quoted
 }
 
+func (s *StringNode) writeTo(sb *strings.Builder) {
+	sb.WriteString(s.String())
+}
+
 func (s *StringNode) tree() *Tree {
 	return s.tr
 }
@@ -690,6 +758,10 @@ func (e *endNode) String() string {
 	return "{{end}}"
 }
 
+func (e *endNode) writeTo(sb *strings.Builder) {
+	sb.WriteString(e.String())
+}
+
 func (e *endNode) tree() *Tree {
 	return e.tr
 }
@@ -718,6 +790,10 @@ func (e *elseNode) String() string {
 	return "{{else}}"
 }
 
+func (e *elseNode) writeTo(sb *strings.Builder) {
+	sb.WriteString(e.String())
+}
+
 func (e *elseNode) tree() *Tree {
 	return e.tr
 }
@@ -738,6 +814,12 @@ type BranchNode struct {
 }
 
 func (b *BranchNode) String() string {
+	var sb strings.Builder
+	b.writeTo(&sb)
+	return sb.String()
+}
+
+func (b *BranchNode) writeTo(sb *strings.Builder) {
 	name := ""
 	switch b.NodeType {
 	case NodeIf:
@@ -749,10 +831,17 @@ func (b *BranchNode) String() string {
 	default:
 		panic("unknown branch type")
 	}
+	sb.WriteString("{{")
+	sb.WriteString(name)
+	sb.WriteByte(' ')
+	b.Pipe.writeTo(sb)
+	sb.WriteString("}}")
+	b.List.writeTo(sb)
 	if b.ElseList != nil {
-		return fmt.Sprintf("{{%s %s}}%s{{else}}%s{{end}}", name, b.Pipe, b.List, b.ElseList)
+		sb.WriteString("{{else}}")
+		b.ElseList.writeTo(sb)
 	}
-	return fmt.Sprintf("{{%s %s}}%s{{end}}", name, b.Pipe, b.List)
+	sb.WriteString("{{end}}")
 }
 
 func (b *BranchNode) tree() *Tree {
@@ -826,10 +915,19 @@ func (t *Tree) newTemplate(pos Pos, line int, name string, pipe *PipeNode) *Temp
 }
 
 func (t *TemplateNode) String() string {
-	if t.Pipe == nil {
-		return fmt.Sprintf("{{template %q}}", t.Name)
+	var sb strings.Builder
+	t.writeTo(&sb)
+	return sb.String()
+}
+
+func (t *TemplateNode) writeTo(sb *strings.Builder) {
+	sb.WriteString("{{template ")
+	sb.WriteString(strconv.Quote(t.Name))
+	if t.Pipe != nil {
+		sb.WriteByte(' ')
+		t.Pipe.writeTo(sb)
 	}
-	return fmt.Sprintf("{{template %q %s}}", t.Name, t.Pipe)
+	sb.WriteString("}}")
 }
 
 func (t *TemplateNode) tree() *Tree {