From 1f109acb780b5a64032f545e9da671c9b5fe84fd Mon Sep 17 00:00:00 2001
From: Sakari Tanskanen <sakari@noice.com>
Date: Thu, 5 May 2022 18:27:21 +0300
Subject: [PATCH 1/2] Allow overlapping methods

Since golang allows overlapping methods in embedded interfaces,
do not fail if overlapping methods are found when merging embedded
interfaces.
---
 generator/generator.go      |  9 +--------
 generator/generator_test.go | 15 ---------------
 2 files changed, 1 insertion(+), 23 deletions(-)

diff --git a/generator/generator.go b/generator/generator.go
index 9d8b83d3..a72b0e1b 100644
--- a/generator/generator.go
+++ b/generator/generator.go
@@ -404,10 +404,7 @@ func processSelector(fs *token.FileSet, currentPackage *packages.Package, se *as
 	return methods, err
 }
 
-var errDuplicateMethod = errors.New("embedded interface has same method")
-
-//mergeMethods merges two methods list, if there is a duplicate method name
-//errDuplicateMethod is returned
+//mergeMethods merges two methods list
 func mergeMethods(ml1, ml2 methodsList) (methodsList, error) {
 	if ml1 == nil || ml2 == nil {
 		return ml1, nil
@@ -419,10 +416,6 @@ func mergeMethods(ml1, ml2 methodsList) (methodsList, error) {
 	}
 
 	for name, signature := range ml2 {
-		if _, ok := ml1[name]; ok {
-			return nil, errors.Wrap(errDuplicateMethod, name)
-		}
-
 		result[name] = signature
 	}
 
diff --git a/generator/generator_test.go b/generator/generator_test.go
index d43bf386..ed544f62 100644
--- a/generator/generator_test.go
+++ b/generator/generator_test.go
@@ -196,21 +196,6 @@ func Test_mergeMethods(t *testing.T) {
 			name:    "nil method",
 			wantErr: false,
 		},
-		{
-			name: "duplicate method",
-			args: args{
-				ml1: methodsList{
-					"method": Method{},
-				},
-				ml2: methodsList{
-					"method": Method{},
-				},
-			},
-			wantErr: true,
-			inspectErr: func(err error, t *testing.T) {
-				assert.Equal(t, errDuplicateMethod, errors.Cause(err))
-			},
-		},
 		{
 			name: "success",
 			args: args{

From b5b167cf545e3880161cd2498b9dfd2c44e0273f Mon Sep 17 00:00:00 2001
From: Sakari Tanskanen <sakari@noice.com>
Date: Thu, 5 May 2022 22:09:20 +0300
Subject: [PATCH 2/2] Always return the outermost overlapping method

---
 generator/generator.go      | 17 +++++++++--------
 generator/generator_test.go | 21 +++++++++++++++++++++
 2 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/generator/generator.go b/generator/generator.go
index a72b0e1b..b60958fa 100644
--- a/generator/generator.go
+++ b/generator/generator.go
@@ -404,18 +404,19 @@ func processSelector(fs *token.FileSet, currentPackage *packages.Package, se *as
 	return methods, err
 }
 
-//mergeMethods merges two methods list
-func mergeMethods(ml1, ml2 methodsList) (methodsList, error) {
-	if ml1 == nil || ml2 == nil {
-		return ml1, nil
+//mergeMethods merges two methods list. Retains overlapping methods from the
+//parent list
+func mergeMethods(methods, embeddedMethods methodsList) (methodsList, error) {
+	if methods == nil || embeddedMethods == nil {
+		return methods, nil
 	}
 
-	result := make(methodsList, len(ml1)+len(ml2))
-	for k, v := range ml1 {
-		result[k] = v
+	result := make(methodsList, len(methods)+len(embeddedMethods))
+	for name, signature := range embeddedMethods {
+		result[name] = signature
 	}
 
-	for name, signature := range ml2 {
+	for name, signature := range methods {
 		result[name] = signature
 	}
 
diff --git a/generator/generator_test.go b/generator/generator_test.go
index ed544f62..d3d02686 100644
--- a/generator/generator_test.go
+++ b/generator/generator_test.go
@@ -196,6 +196,27 @@ func Test_mergeMethods(t *testing.T) {
 			name:    "nil method",
 			wantErr: false,
 		},
+		{
+			name: "duplicate methods should return outer method",
+			args: args{
+				ml1: methodsList{
+					"method": Method{
+						Doc: []string{"outer"},
+					},
+				},
+				ml2: methodsList{
+					"method": Method{
+						Doc: []string{"inner"},
+					},
+				},
+			},
+			wantErr: false,
+			want1: methodsList{
+				"method": {
+					Doc: []string{"outer"},
+				},
+			},
+		},
 		{
 			name: "success",
 			args: args{