Remove named returns from ReadBranchConfig and surface errors

git/client.go

@@ -377,16 +377,22 @@ func (c *Client) lookupCommit(ctx context.Context, sha, format string) ([]byte,
 }
 
 // ReadBranchConfig parses the `branch.BRANCH.(remote|merge|gh-merge-base)` part of git config.
-func (c *Client) ReadBranchConfig(ctx context.Context, branch string) (cfg BranchConfig) {
+// If no branch config is found or there is an error in the command, it returns an empty BranchConfig.
+// Downstream consumers of ReadBranchConfig should consider the behavior they desire if this errors,
+// as an empty config is not necessarily breaking.
+func (c *Client) ReadBranchConfig(ctx context.Context, branch string) (BranchConfig, error) {
+	var cfg BranchConfig
+
 	prefix := regexp.QuoteMeta(fmt.Sprintf("branch.%s.", branch))
 	args := []string{"config", "--get-regexp", fmt.Sprintf("^%s(remote|merge|%s)$", prefix, MergeBaseConfig)}
 	cmd, err := c.Command(ctx, args...)
 	if err != nil {
-		return
+		return cfg, err
 	}
+
 	out, err := cmd.Output()
 	if err != nil {
-		return
+		return cfg, err
 	}
 
 	for _, line := range outputLines(out) {
@@ -412,7 +418,7 @@ func (c *Client) ReadBranchConfig(ctx context.Context, branch string) (cfg Branc
 			cfg.MergeBase = parts[1]
 		}
 	}
-	return
+	return cfg, nil
 }
 
 // SetBranchConfig sets the named value on the given branch.

git/client_test.go

@@ -747,7 +747,7 @@ func TestClientReadBranchConfig(t *testing.T) {
 				GitPath:        "path/to/git",
 				commandContext: cmdCtx,
 			}
-			branchConfig := client.ReadBranchConfig(context.Background(), "trunk")
+			branchConfig, _ := client.ReadBranchConfig(context.Background(), "trunk")
 			assert.Equal(t, tt.wantCmdArgs, strings.Join(cmd.Args[3:], " "))
 			assert.Equal(t, tt.wantBranchConfig, branchConfig)
 		})

pkg/cmd/pr/create/create.go

@@ -680,7 +680,11 @@ func NewCreateContext(opts *CreateOptions) (*CreateContext, error) {
 	var headRepo ghrepo.Interface
 	var headRemote *ghContext.Remote
 
-	headBranchConfig := gitClient.ReadBranchConfig(context.Background(), headBranch)
+	headBranchConfig, err := gitClient.ReadBranchConfig(context.Background(), headBranch)
+	if err != nil {
+		// We can still proceed without the branch config, so print to stderr but continue
+		fmt.Fprintf(opts.IO.ErrOut, "Error reading git branch config: %v\n", err)
+	}
 	if isPushEnabled {
 		// determine whether the head branch is already pushed to a remote
 		if trackingRef, found := tryDetermineTrackingRef(gitClient, remotes, headBranch, headBranchConfig); found {

pkg/cmd/pr/create/create_test.go

@@ -1717,7 +1717,7 @@ func Test_tryDetermineTrackingRef(t *testing.T) {
 				GhPath:  "some/path/gh",
 				GitPath: "some/path/git",
 			}
-			headBranchConfig := gitClient.ReadBranchConfig(ctx.Background(), "feature")
+			headBranchConfig, _ := gitClient.ReadBranchConfig(ctx.Background(), "feature")
 			ref, found := tryDetermineTrackingRef(gitClient, tt.remotes, "feature", headBranchConfig)
 
 			assert.Equal(t, tt.expectedTrackingRef, ref)

pkg/cmd/pr/shared/finder.go

@@ -59,7 +59,8 @@ func NewFinder(factory *cmdutil.Factory) PRFinder {
 		httpClient: factory.HttpClient,
 		progress:   factory.IOStreams,
 		branchConfig: func(s string) git.BranchConfig {
-			return factory.GitClient.ReadBranchConfig(context.Background(), s)
+			branchConfig, _ := factory.GitClient.ReadBranchConfig(context.Background(), s)
+			return branchConfig
 		},
 	}
 }

pkg/cmd/pr/status/status.go

@@ -186,7 +186,7 @@ func statusRun(opts *StatusOptions) error {
 
 func prSelectorForCurrentBranch(gitClient *git.Client, baseRepo ghrepo.Interface, prHeadRef string, rem ghContext.Remotes) (prNumber int, selector string, err error) {
 	selector = prHeadRef
-	branchConfig := gitClient.ReadBranchConfig(context.Background(), prHeadRef)
+	branchConfig, _ := gitClient.ReadBranchConfig(context.Background(), prHeadRef)
 
 	// the branch is configured to merge a special PR head ref
 	prHeadRE := regexp.MustCompile(`^refs/pull/(\d+)/head$`)