From 177da717a76d985436c283194229ca3b28a0f597 Mon Sep 17 00:00:00 2001
From: 6543 <6543@obermui.de>
Date: Mon, 8 Mar 2021 21:48:31 +0100
Subject: [PATCH] [API] get pull, return head branch sha, even if deleted
 (#14931)

* API: return head branch sha, even if deleted

* relax if ref not resolvable
---
 modules/convert/pull.go | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/modules/convert/pull.go b/modules/convert/pull.go
index 87eabcf53a98..3c24f4532f3c 100644
--- a/modules/convert/pull.go
+++ b/modules/convert/pull.go
@@ -134,6 +134,24 @@ func ToAPIPullRequest(pr *models.PullRequest) *api.PullRequest {
 		}
 	}
 
+	if len(apiPullRequest.Head.Sha) == 0 && len(apiPullRequest.Head.Ref) != 0 {
+		baseGitRepo, err := git.OpenRepository(pr.BaseRepo.RepoPath())
+		if err != nil {
+			log.Error("OpenRepository[%s]: %v", pr.BaseRepo.RepoPath(), err)
+			return nil
+		}
+		defer baseGitRepo.Close()
+		refs, err := baseGitRepo.GetRefsFiltered(apiPullRequest.Head.Ref)
+		if err != nil {
+			log.Error("GetRefsFiltered[%s]: %v", apiPullRequest.Head.Ref, err)
+			return nil
+		} else if len(refs) == 0 {
+			log.Error("unable to resolve PR head ref")
+		} else {
+			apiPullRequest.Head.Sha = refs[0].Object.String()
+		}
+	}
+
 	if pr.Status != models.PullRequestStatusChecking {
 		mergeable := !(pr.Status == models.PullRequestStatusConflict || pr.Status == models.PullRequestStatusError) && !pr.IsWorkInProgress()
 		apiPullRequest.Mergeable = mergeable