fix Go struct tag parsing

304ba5d didn't correctly handle struct tags whose
value contained a space. (My fault.)

Use a proper struct tag library with a dedicated parser
that handles all the edge cases. Less code, and better.

Author: josharian

go.mod

@@ -33,6 +33,7 @@ require (
 
 require (
 	github.com/cznic/mathutil v0.0.0-20181122101859-297441e03548 // indirect
+	github.com/fatih/structtag v1.2.0 // indirect
 	github.com/golang/protobuf v1.5.3 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/jackc/chunkreader/v2 v2.0.1 // indirect

go.sum

@@ -20,6 +20,8 @@ github.com/cznic/mathutil v0.0.0-20181122101859-297441e03548/go.mod h1:e6NPNENfs
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/fatih/structtag v1.2.0 h1:/OdNE99OxoI/PqaW/SuSK9uxxT3f/tcSZgon/ssNSx4=
+github.com/fatih/structtag v1.2.0/go.mod h1:mBJUNpUnHmRKrKlQQlmCrh5PuhftFbNv8Ys4/aAZl94=
 github.com/go-kit/log v0.1.0/go.mod h1:zbhenjAZHb184qTLMA9ZjW7ThYL0H2mk7Q6pNt4vbaY=
 github.com/go-logfmt/logfmt v0.5.0/go.mod h1:wCYkCAKZfumFQihp8CzCvQ3paCTfi41vtzG1KdI/P7A=
 github.com/go-sql-driver/mysql v1.7.1 h1:lUIinVbN1DY0xBg0eMOzmmtGoHwWBbvnWubQUrtU8EI=

internal/config/go_type.go

@@ -6,6 +6,8 @@ import (
 	"go/types"
 	"regexp"
 	"strings"
+
+	"github.com/fatih/structtag"
 )
 
 type GoType struct {
@@ -171,16 +173,12 @@ type GoStructTag string
 // `a:"b" x:"y,z"`   {"a": "b", "x": "y,z"}
 func (s GoStructTag) Parse() (map[string]string, error) {
 	m := make(map[string]string)
-	fields := strings.Fields(string(s))
-	for _, f := range fields {
-		k, v, ok := strings.Cut(f, ":")
-		if !ok {
-			return nil, fmt.Errorf("Failed to parse Go struct tag: no colon in field %q", f)
-		}
-		if len(v) < 2 || v[0] != '"' || v[len(v)-1] != '"' {
-			return nil, fmt.Errorf("Failed to parse Go struct tag: missing quotes around value in field %q", f)
-		}
-		m[k] = v[1 : len(v)-1] // trim quotes off of v
+	tags, err := structtag.Parse(string(s))
+	if err != nil {
+		return nil, err
+	}
+	for _, tag := range tags.Tags() {
+		m[tag.Key] = tag.Value()
 	}
 	return m, nil
 }

internal/endtoend/testdata/overrides_go_struct_tags/invalid_tags/stderr.txt

@@ -1 +1 @@
-error parsing sqlc.json: Failed to parse Go struct tag: no colon in field "abc"
+error parsing sqlc.json: bad syntax for struct tag pair

internal/endtoend/testdata/overrides_go_struct_tags/sqlite/go/models.go

@@ -1,14 +1,17 @@
 CREATE TABLE foo (
     other     text NOT NULL,
-    tagged    text NOT NULL
+    tagged    text NOT NULL,
+    tag3      text NOT NULL
 );
 
 CREATE TABLE bar (
     other          text NOT NULL,
-    also_tagged    text NOT NULL
+    also_tagged    text NOT NULL,
+    tag3           text NOT NULL
 );
 
 CREATE TABLE baz (
     other          text NOT NULL,
-    also_tagged    text NOT NULL
+    also_tagged    text NOT NULL,
+    tag3           text NOT NULL
 );

internal/endtoend/testdata/overrides_go_struct_tags/sqlite/schema.sql

@@ -15,6 +15,10 @@
         {
           "go_struct_tag": "also:\"tagged\"",
           "column": "*.also_tagged"
+        },
+        {
+          "go_struct_tag": "tag_with_space:\" it's legal!\"",
+          "column": "*.tag3"
         }
       ]
     }