[gomonorepo] - fix compare branch when parent is remote

gomonorepo/cmd/gomonorepo/main.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"context"
-	"fmt"
 	"os"
 	"os/signal"
 	"syscall"
@@ -50,6 +49,6 @@ func main() {
 	if fErr, ok := err.(*flags.Error); ok && fErr.Type == flags.ErrHelp {
 		parser.WriteHelp(os.Stdout)
 	} else if err != nil {
-		fmt.Fprint(os.Stderr, err.Error())
+		opts.Errorf("Fatal: %s", err.Error())
 	}
 }

gomonorepo/git_commands.go

@@ -24,7 +24,7 @@ func getIgnoredDirectories(
 	cmd.Stderr = stderr
 	err := cmd.Run()
 	if err != nil {
-		return nil, fmt.Errorf("failed to run git diff: %w\n%s", err, stderr.String())
+		return nil, fmt.Errorf("failed to get ignored files: %w\n%s", err, stderr.String())
 	}
 
 	result := make([]string, 0, 8)
@@ -41,7 +41,7 @@ func getIgnoredDirectories(
 	return result, nil
 }
 
-func listChangedFiles(ctx context.Context, parent string) ([]string, error) {
+func listChangedFiles(ctx context.Context, opts *AppOptions, parent string, patched bool) ([]string, error) {
 	stdout, done := GetBuffer()
 	defer done(stdout)
 	stderr, done := GetBuffer()
@@ -51,6 +51,14 @@ func listChangedFiles(ctx context.Context, parent string) ([]string, error) {
 	cmd.Stderr = stderr
 	err := cmd.Run()
 	if err != nil {
+		if !patched && strings.HasPrefix(stderr.String(), "fatal: ambiguous argument '"+parent+"'") {
+			opts.Infof("Parent %q not found locally, attempting to fetch it from remote.\n", parent)
+			err = tryFetchParentRevision(ctx, parent)
+			if err != nil {
+				return nil, err
+			}
+			return listChangedFiles(ctx, opts, parent, true)
+		}
 		return nil, fmt.Errorf("failed to run git diff: %w\n%s", err, stderr.String())
 	}
 
@@ -66,18 +74,84 @@ func listChangedFiles(ctx context.Context, parent string) ([]string, error) {
 	return result, nil
 }
 
+func tryFetchParentRevision(ctx context.Context, parent string) error {
+	remote, err := getConfiguredRemoteName(ctx)
+	if err != nil {
+		return err
+	}
+	branch := parent
+	if strings.HasPrefix(parent, remote) {
+		branch = strings.TrimPrefix(parent, remote+"/")
+	}
+
+	stdout, done := GetBuffer()
+	defer done(stdout)
+	stderr, done := GetBuffer()
+	defer done(stderr)
+
+	cmd := exec.CommandContext(ctx, "git", "fetch", remote, branch)
+	cmd.Stdout = stdout
+	cmd.Stderr = stderr
+	err = cmd.Run()
+	if err != nil {
+		return fmt.Errorf("failed to fetch parent revision: %w\n%s", err, stderr.String())
+	}
+	return nil
+}
+
+// getConfiguredRemoteName returns the first remote name configured in the git repository.
+func getConfiguredRemoteName(ctx context.Context) (string, error) {
+	stdout, done := GetBuffer()
+	defer done(stdout)
+	stderr, done := GetBuffer()
+	defer done(stderr)
+
+	cmd := exec.CommandContext(ctx, "git", "remote")
+	cmd.Stdout = stdout
+	cmd.Stderr = stderr
+	err := cmd.Run()
+	if err != nil {
+		return "", fmt.Errorf("failed to get remote name: %w\n%s", err, stderr.String())
+	}
+
+	// Get the first remote name
+	remotes := strings.Split(stdout.String(), "\n")
+	if len(remotes) == 0 {
+		return "", fmt.Errorf("no remotes found")
+	}
+
+	return remotes[0], nil
+}
+
 // getCurrentBranch returns the current branch name.
-func getCurrentBranch(ctx context.Context) (string, error) {
+func getCurrentBranch(ctx context.Context) (remote string, branch string, err error) {
 	stdout, done := GetBuffer()
 	defer done(stdout)
 	stderr, done := GetBuffer()
 	defer done(stderr)
+
+	// Get the current branch / revision name excluding the remote:
 	cmd := exec.CommandContext(ctx, "git", "rev-parse", "--abbrev-ref", "HEAD")
 	cmd.Stdout = stdout
 	cmd.Stderr = stderr
-	err := cmd.Run()
+	err = cmd.Run()
+	if err != nil {
+		return "", "", fmt.Errorf("failed to get branch name: %w\n%s", err, stderr.String())
+	}
+	branch = strings.TrimSpace(stdout.String())
+
+	stdout.Reset()
+	stderr.Reset()
+
+	// Get the branch name AND its upstream remote (e.g. origin/main):
+	cmd = exec.CommandContext(ctx, "git", "rev-parse", "--abbrev-ref", "--symbolic-full-name", "@{upstream}")
+	cmd.Stdout = stdout
+	cmd.Stderr = stderr
+	err = cmd.Run()
 	if err != nil {
-		return "", fmt.Errorf("failed to run git diff: %w\n%s", err, stderr.String())
+		// noop. there is no remote.
+		return "", branch, nil
 	}
-	return strings.TrimSpace(stdout.String()), nil
+	remote = strings.TrimSuffix(strings.TrimSpace(stdout.String()), "/"+branch)
+	return remote, branch, nil
 }

gomonorepo/module_changes.go

@@ -33,16 +33,16 @@ func listAllChangedModulesWithTree(
 		return set.Make(tree.AllModules...), nil
 	}
 
-	changedFiles, err := listChangedFiles(ctx, parentCommit)
+	changedFiles, err := listChangedFiles(ctx, opts, parentCommit, false)
 	if err != nil {
 		return nil, err
 	}
 	if len(changedFiles) == 0 {
-		current, err := getCurrentBranch(ctx)
+		remote, current, err := getCurrentBranch(ctx)
 		if err != nil {
 			return nil, err
 		}
-		if current == parentCommit {
+		if current == parentCommit || remote+"/"+current == parentCommit {
 			opts.Infof("Currently on %q with no changes; will run command on all %d moduels.\n",
 				current,
 				len(tree.AllModules))