Push refs instead of creating local branches

Fixes: #87

commit-id:5b5cbd54

git/mockgit/mockgit.go

@@ -69,17 +69,12 @@ func (m *mock) ExpectLogAndRespond(commits []*git.Commit) {
 func (m *mock) ExpectPushCommits(commits []*git.Commit) {
 	m.expect("git status --porcelain --untracked-files=no").respond(nil)
 
-	var branchNames []string
+	var refNames []string
 	for _, c := range commits {
-		m.expect("git checkout %s", c.CommitHash)
-		m.expect("git switch -C pr/TestSPR/master/%s", c.CommitID)
-		m.expect("git switch master")
-		branchNames = append(branchNames, "pr/TestSPR/master/"+c.CommitID)
-	}
-	m.expect("git push --force --atomic origin " + strings.Join(branchNames, " "))
-	for _, c := range commits {
-		m.expect("git branch -D pr/TestSPR/master/%s", c.CommitID)
+		branchName := "pr/TestSPR/master/" + c.CommitID
+		refNames = append(refNames, c.CommitHash+":refs/heads/"+branchName)
 	}
+	m.expect("git push --force --atomic origin " + strings.Join(refNames, " "))
 }
 
 func (m *mock) expect(cmd string, args ...interface{}) *mock {

spr/spr.go

@@ -399,34 +399,18 @@ func (sd *stackediff) syncCommitStackToGitHub(ctx context.Context,
 		}
 	}
 
-	var branchNames []string
+	var refNames []string
 	for _, commit := range updatedCommits {
-		branch := sd.branchNameFromCommit(info, commit)
-		branchNames = append(branchNames, branch)
-		sd.mustgit("checkout "+commit.CommitHash, nil)
-		sd.mustgit("switch -C "+branch, nil)
-		sd.mustgit("switch "+info.LocalBranch, nil)
-		sd.profiletimer.Step("SyncCommitStack::CreateBranch::" + branch)
+		branchName := sd.branchNameFromCommit(info, commit)
+		refNames = append(refNames,
+			commit.CommitHash+":refs/heads/"+branchName)
 	}
 	if len(updatedCommits) > 0 {
-		sd.mustgit("push --force --atomic origin "+strings.Join(branchNames, " "), nil)
-	}
-	for _, commit := range updatedCommits {
-		branch := sd.branchNameFromCommit(info, commit)
-		sd.mustgit("branch -D "+branch, nil)
+		sd.mustgit("push --force --atomic origin "+strings.Join(refNames, " "), nil)
 	}
 	sd.profiletimer.Step("SyncCommitStack::PushBranches")
 }
 
-func (sd *stackediff) pushCommitToRemote(commit git.Commit, info *github.GitHubInfo) {
-	headRefName := sd.branchNameFromCommit(info, commit)
-	sd.mustgit("checkout "+commit.CommitHash, nil)
-	sd.mustgit("switch -C "+headRefName, nil)
-	sd.mustgit("push --force --set-upstream origin "+headRefName, nil)
-	sd.mustgit("switch "+info.LocalBranch, nil)
-	sd.mustgit("branch -D "+headRefName, nil)
-}
-
 func (sd *stackediff) branchNameFromCommit(info *github.GitHubInfo, commit git.Commit) string {
 	return "pr/" + info.UserName + "/" + info.LocalBranch + "/" + commit.CommitID
 }