fix(golang): unescape double quotes in go tags

Author: lsjbd

docs/string-literals-in-the-IDL.md

@@ -56,4 +56,8 @@ func NewS() *S {
 }
 ```
 
-Note that it is malformed to escape a single quote in a double quoted literal or vice versa.
+Note that it is unnecessary to escape a single quote in a double quoted literal or vice versa.
+But for compatibility with existing IDLs, escaped double quotes in a quoted literal is allowed in go generator by default. It can be disabled by specifying `unescape_double_quote=false`.
+
+
+

generator/golang/option.go

@@ -39,7 +39,8 @@ type Features struct {
 	CompatibleNames    bool `compatible_names:"Add a '_' suffix if an name has a prefix 'New' or suffix 'Args' or 'Result'."`
 	ReserveComments    bool `reserve_comments:"Reserve comments of definitions in thrift file"`
 	NilSafe            bool `nil_safe:"Generate nil-safe getters."`
-	FrugalTag          bool `frugal_tag:"generate 'frugal' tag"`
+	FrugalTag          bool `frugal_tag:"Generate 'frugal' tags."`
+	EscapeDoubleInTag  bool `unescape_double_quote:"Unescape the double quotes in literals when generating go tags."`
 }
 
 var defaultFeatures = Features{
@@ -59,6 +60,7 @@ var defaultFeatures = Features{
 	ReserveComments:    false,
 	NilSafe:            false,
 	FrugalTag:          false,
+	EscapeDoubleInTag:  true,
 }
 
 type param struct {

generator/golang/util.go

@@ -17,6 +17,7 @@ package golang
 import (
 	"fmt"
 	"path/filepath"
+	"regexp"
 	"strings"
 	"text/template"
 
@@ -34,6 +35,8 @@ const (
 	DefaultUnknownLib = "github.com/cloudwego/thriftgo/generator/golang/extension/unknown"
 )
 
+var escape = regexp.MustCompile(`\\.`)
+
 // CodeUtils contains a set of utility functions.
 type CodeUtils struct {
 	backend.LogFunc
@@ -196,7 +199,16 @@ func (cu *CodeUtils) GenTags(f *parser.Field, insertPoint string) (string, error
 	}
 
 	if gotags := f.Annotations.Get("go.tag"); len(gotags) > 0 {
-		tags = append(tags, gotags[0])
+		tag := gotags[0]
+		if cu.Features().EscapeDoubleInTag {
+			tag = escape.ReplaceAllStringFunc(tag, func(m string) string {
+				if m[1] == '"' {
+					return m[1:]
+				}
+				return m
+			})
+		}
+		tags = append(tags, tag)
 	} else {
 		if cu.Features().GenDatabaseTag {
 			tags = append(tags, fmt.Sprintf(`db:"%s"`, f.Name))