From 60744df04c2b17dbfc168b2eb78296649ad1403b Mon Sep 17 00:00:00 2001
From: 6543 <6543@obermui.de>
Date: Fri, 3 Apr 2020 02:29:54 +0200
Subject: [PATCH 1/3] use pull.MergedCommitID for merged pulls

---
 routers/repo/pull.go | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/routers/repo/pull.go b/routers/repo/pull.go
index c29cfb81b22d0..9c39d1bc4b356 100644
--- a/routers/repo/pull.go
+++ b/routers/repo/pull.go
@@ -1162,6 +1162,22 @@ func DownloadPullDiffOrPatch(ctx *context.Context, patch bool) {
 
 	pr := issue.PullRequest
 
+	if pr.HasMerged {
+		diffType := git.RawDiffType("diff")
+		if patch {
+			diffType = git.RawDiffType("patch")
+		}
+		if err := git.GetRawDiff(
+			models.RepoPath(ctx.Repo.Owner.Name, ctx.Repo.Repository.Name),
+			pr.MergedCommitID,
+			diffType,
+			ctx.Resp,
+		); err != nil {
+			ctx.ServerError("GetRawDiff", err)
+			return
+		}
+	}
+
 	if err := pull_service.DownloadDiffOrPatch(pr, ctx, patch); err != nil {
 		ctx.ServerError("DownloadDiffOrPatch", err)
 		return

From d3ccc1b4f52be140a03e87917e6e77a54237d801 Mon Sep 17 00:00:00 2001
From: 6543 <6543@obermui.de>
Date: Fri, 3 Apr 2020 03:18:13 +0200
Subject: [PATCH 2/3] use Constants

---
 routers/repo/pull.go | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/routers/repo/pull.go b/routers/repo/pull.go
index 9c39d1bc4b356..309cd5cbcf2bf 100644
--- a/routers/repo/pull.go
+++ b/routers/repo/pull.go
@@ -1163,9 +1163,9 @@ func DownloadPullDiffOrPatch(ctx *context.Context, patch bool) {
 	pr := issue.PullRequest
 
 	if pr.HasMerged {
-		diffType := git.RawDiffType("diff")
+		diffType := git.RawDiffNormal
 		if patch {
-			diffType = git.RawDiffType("patch")
+			diffType = git.RawDiffPatch
 		}
 		if err := git.GetRawDiff(
 			models.RepoPath(ctx.Repo.Owner.Name, ctx.Repo.Repository.Name),

From adb549fec1b0d4de3b5b77f6fe62987ff3860f63 Mon Sep 17 00:00:00 2001
From: 6543 <6543@obermui.de>
Date: Fri, 3 Apr 2020 03:39:39 +0200
Subject: [PATCH 3/3] Apply suggestions from code review

---
 routers/repo/pull.go | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/routers/repo/pull.go b/routers/repo/pull.go
index 309cd5cbcf2bf..423c1e188201d 100644
--- a/routers/repo/pull.go
+++ b/routers/repo/pull.go
@@ -1171,11 +1171,12 @@ func DownloadPullDiffOrPatch(ctx *context.Context, patch bool) {
 			models.RepoPath(ctx.Repo.Owner.Name, ctx.Repo.Repository.Name),
 			pr.MergedCommitID,
 			diffType,
-			ctx.Resp,
+			ctx,
 		); err != nil {
 			ctx.ServerError("GetRawDiff", err)
 			return
 		}
+	return
 	}
 
 	if err := pull_service.DownloadDiffOrPatch(pr, ctx, patch); err != nil {