diff --git a/modules/git/repo_compare.go b/modules/git/repo_compare.go
index f60696a763..8d26f1e9e7 100644
--- a/modules/git/repo_compare.go
+++ b/modules/git/repo_compare.go
@@ -18,32 +18,6 @@ import (
 	"code.gitea.io/gitea/modules/git/gitcmd"
 )
 
-// GetMergeBase checks and returns merge base of two branches and the reference used as base.
-func (repo *Repository) GetMergeBase(tmpRemote, base, head string) (string, string, error) {
-	if tmpRemote == "" {
-		tmpRemote = "origin"
-	}
-
-	if tmpRemote != "origin" {
-		tmpBaseName := RemotePrefix + tmpRemote + "/tmp_" + base
-		// Fetch commit into a temporary branch in order to be able to handle commits and tags
-		_, _, err := gitcmd.NewCommand("fetch", "--no-tags").
-			AddDynamicArguments(tmpRemote).
-			AddDashesAndList(base + ":" + tmpBaseName).
-			WithDir(repo.Path).
-			RunStdString(repo.Ctx)
-		if err == nil {
-			base = tmpBaseName
-		}
-	}
-
-	stdout, _, err := gitcmd.NewCommand("merge-base").
-		AddDashesAndList(base, head).
-		WithDir(repo.Path).
-		RunStdString(repo.Ctx)
-	return strings.TrimSpace(stdout), base, err
-}
-
 type lineCountWriter struct {
 	numLines int
 }
diff --git a/modules/gitrepo/merge.go b/modules/gitrepo/merge.go
index 3c317491e5..2d83a1eb2b 100644
--- a/modules/gitrepo/merge.go
+++ b/modules/gitrepo/merge.go
@@ -12,23 +12,23 @@ import (
 )
 
 // MergeBase checks and returns merge base of two commits.
-func MergeBase(ctx context.Context, repo Repository, commit1, commit2 string) (string, error) {
+func MergeBase(ctx context.Context, repo Repository, baseCommitID, headCommitID string) (string, error) {
 	mergeBase, err := RunCmdString(ctx, repo, gitcmd.NewCommand("merge-base").
-		AddDashesAndList(commit1, commit2))
+		AddDashesAndList(baseCommitID, headCommitID))
 	if err != nil {
-		return "", fmt.Errorf("get merge-base of %s and %s failed: %w", commit1, commit2, err)
+		return "", fmt.Errorf("get merge-base of %s and %s failed: %w", baseCommitID, headCommitID, err)
 	}
 	return strings.TrimSpace(mergeBase), nil
 }
 
 // MergeBaseFromRemote checks and returns merge base of two commits from different repositories.
-func MergeBaseFromRemote(ctx context.Context, repo, remoteRepo Repository, commit1, commit2 string) (string, error) {
+func MergeBaseFromRemote(ctx context.Context, baseRepo, headRepo Repository, baseCommitID, headCommitID string) (string, error) {
 	// fetch head commit id into the current repository if the repositories are different
-	if repo.RelativePath() != remoteRepo.RelativePath() {
-		if err := FetchRemoteCommit(ctx, repo, remoteRepo, commit2); err != nil {
+	if baseRepo.RelativePath() != headRepo.RelativePath() {
+		if err := FetchRemoteCommit(ctx, baseRepo, headRepo, headCommitID); err != nil {
 			return "", fmt.Errorf("FetchRemoteCommit: %w", err)
 		}
 	}
 
-	return MergeBase(ctx, repo, commit1, commit2)
+	return MergeBase(ctx, baseRepo, baseCommitID, headCommitID)
 }
diff --git a/services/migrations/gitea_uploader.go b/services/migrations/gitea_uploader.go
index 9e1a1f2e95..b7b1631d8d 100644
--- a/services/migrations/gitea_uploader.go
+++ b/services/migrations/gitea_uploader.go
@@ -736,7 +736,7 @@ func (g *GiteaLocalUploader) newPullRequest(ctx context.Context, pr *base.PullRe
 		if pr.Base.Ref != "" && pr.Head.SHA != "" {
 			// A PR against a tag base does not make sense - therefore pr.Base.Ref must be a branch
 			// TODO: should we be checking for the refs/heads/ prefix on the pr.Base.Ref? (i.e. are these actually branches or refs)
-			pr.Base.SHA, _, err = g.gitRepo.GetMergeBase("", git.BranchPrefix+pr.Base.Ref, pr.Head.SHA)
+			pr.Base.SHA, err = gitrepo.MergeBase(ctx, g.repo, git.BranchPrefix+pr.Base.Ref, pr.Head.SHA)
 			if err != nil {
 				log.Error("Cannot determine the merge base for PR #%d in %s/%s. Error: %v", pr.Number, g.repoOwner, g.repoName, err)
 			}
diff --git a/services/pull/pull.go b/services/pull/pull.go
index ecc0b2c7ce..165e275021 100644
--- a/services/pull/pull.go
+++ b/services/pull/pull.go
@@ -510,14 +510,7 @@ func checkIfPRContentChanged(ctx context.Context, pr *issues_model.PullRequest,
 	}
 	defer cancel()
 
-	tmpRepo, err := git.OpenRepository(ctx, prCtx.tmpBasePath)
-	if err != nil {
-		return false, "", fmt.Errorf("OpenRepository: %w", err)
-	}
-	defer tmpRepo.Close()
-
-	// Find the merge-base
-	mergeBase, _, err = tmpRepo.GetMergeBase("", "base", "tracking")
+	mergeBase, err = gitrepo.MergeBaseFromRemote(ctx, pr.BaseRepo, pr.HeadRepo, pr.BaseBranch, pr.HeadBranch)
 	if err != nil {
 		return false, "", fmt.Errorf("GetMergeBase: %w", err)
 	}