reflect: fix test of whether structs are identical

The old code worked with gc, I assume because the linker
unified identical strings, but it failed with gccgo.

R=rsc
CC=gobot, golang-dev
https://golang.org/cl/6826063

diff --git a/src/pkg/reflect/type.go b/src/pkg/reflect/type.go
index 5e3856b1c37b471dff0ac20db5cd2c450dad906b..3a2146ce8dfe39732b59d5295d00991c917c48d3 100644 (file)
--- a/src/pkg/reflect/type.go
+++ b/src/pkg/reflect/type.go
@@ -1257,8 +1257,19 @@ func haveIdenticalUnderlyingType(T, V *commonType) bool {
                for i := range t.fields {
                        tf := &t.fields[i]
                        vf := &v.fields[i]
-                       if tf.name != vf.name || tf.pkgPath != vf.pkgPath ||
-                               tf.typ != vf.typ || tf.tag != vf.tag || tf.offset != vf.offset {
+                       if tf.name != vf.name && (tf.name == nil || vf.name == nil || *tf.name != *vf.name) {
+                               return false
+                       }
+                       if tf.pkgPath != vf.pkgPath && (tf.pkgPath == nil || vf.pkgPath == nil || *tf.pkgPath != *vf.pkgPath) {
+                               return false
+                       }
+                       if tf.typ != vf.typ {
+                               return false
+                       }
+                       if tf.tag != vf.tag && (tf.tag == nil || vf.tag == nil || *tf.tag != *vf.tag) {
+                               return false
+                       }
+                       if tf.offset != vf.offset {
                                return false
                        }
                }

diff --git a/test/fixedbugs/bug468.dir/p1.go b/test/fixedbugs/bug468.dir/p1.go
new file mode 100644 (file)
index 0000000..ca17577
--- /dev/null
+++ b/test/fixedbugs/bug468.dir/p1.go
@@ -0,0 +1,7 @@
+// Copyright 2012 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 p1
+
+type S struct { X, Y int }

diff --git a/test/fixedbugs/bug468.dir/p2.go b/test/fixedbugs/bug468.dir/p2.go
new file mode 100644 (file)
index 0000000..1793c0e
--- /dev/null
+++ b/test/fixedbugs/bug468.dir/p2.go
@@ -0,0 +1,25 @@
+// Copyright 2012 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 main
+
+import (
+       "reflect"
+
+       "./p1"
+)
+
+func main() {
+       var v1 = p1.S{1, 2}
+       var v2 = struct { X, Y int }{1, 2}
+       v1 = v2
+       t1 := reflect.TypeOf(v1)
+       t2 := reflect.TypeOf(v2)
+       if !t1.AssignableTo(t2) {
+               panic(0)
+       }
+       if !t2.AssignableTo(t1) {
+               panic(1)
+       }
+}

diff --git a/test/fixedbugs/bug468.go b/test/fixedbugs/bug468.go
new file mode 100644 (file)
index 0000000..12e4997
--- /dev/null
+++ b/test/fixedbugs/bug468.go
@@ -0,0 +1,10 @@
+// rundir
+
+// Copyright 2012 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.
+
+// The reflect package was not correctly checking field names
+// when checking for struct assignability.
+
+package ignored