Merge pull request #44 from go-test/dn/fix-issue-39

Fix issue 39: Confusing diff when comparing distinct types with the ame name

.travis.yml

@@ -1,13 +1,13 @@
 language: go
 
 go:
-  - "1.11"
   - "1.12"
   - "1.13"
+  - "1.14"
 
 before_install:
   - go get github.com/mattn/goveralls
   - go get golang.org/x/tools/cover
 
 script:
-  - $HOME/gopath/bin/goveralls -service=travis-ci
+  - $HOME/gopath/bin/goveralls -service=travis-ci -package github.com/go-test/deep

deep.go

@@ -112,7 +112,18 @@ func (c *cmp) equals(a, b reflect.Value, level int) {
 	aType := a.Type()
 	bType := b.Type()
 	if aType != bType {
-		c.saveDiff(aType, bType)
+		// Built-in types don't have a name, so don't report [3]int != [2]int as " != "
+		if aType.Name() == "" || aType.Name() != bType.Name() {
+			c.saveDiff(aType, bType)
+		} else {
+			// Type names can be the same, e.g. pkg/v1.Error and pkg/v2.Error
+			// are both exported as pkg, so unless we include the full pkg path
+			// the diff will be "pkg.Error != pkg.Error"
+			// https://github.com/go-test/deep/issues/39
+			aFullType := aType.PkgPath() + "." + aType.Name()
+			bFullType := bType.PkgPath() + "." + bType.Name()
+			c.saveDiff(aFullType, bFullType)
+		}
 		logError(ErrTypeMismatch)
 		return
 	}

deep_test.go

@@ -8,6 +8,8 @@ import (
 	"time"
 
 	"github.com/go-test/deep"
+	v1 "github.com/go-test/deep/test/v1"
+	v2 "github.com/go-test/deep/test/v2"
 )
 
 func TestString(t *testing.T) {
@@ -135,6 +137,21 @@ func TestTypeMismatch(t *testing.T) {
 	if diff[0] != "deep_test.T1 != deep_test.T2" {
 		t.Error("wrong diff:", diff[0])
 	}
+
+	// Same pkg name but differnet full paths
+	// https://github.com/go-test/deep/issues/39
+	err1 := v1.Error{}
+	err2 := v2.Error{}
+	diff = deep.Equal(err1, err2)
+	if diff == nil {
+		t.Fatal("no diff")
+	}
+	if len(diff) != 1 {
+		t.Error("too many diff:", diff)
+	}
+	if diff[0] != "github.com/go-test/deep/test/v1.Error != github.com/go-test/deep/test/v2.Error" {
+		t.Error("wrong diff:", diff[0])
+	}
 }
 
 func TestKindMismatch(t *testing.T) {

test/v1/errors.go

@@ -0,0 +1,7 @@
+package deeptest
+
+type Error struct{}
+
+func (e Error) Error() string {
+	return ""
+}

test/v2/errors.go

@@ -0,0 +1,7 @@
+package deeptest
+
+type Error struct{}
+
+func (e Error) Error() string {
+	return ""
+}