What causes "no Go package found in %q" in github/copilot-sdk?

Verify the directory path contains at least one valid .go file

no Go package found in

Error message

no Go package found in %q

What it means

If the directory walk finishes without any successfully parsed package clause, detectPackageName cannot determine a package name and returns this error with the defaultPackageName fallback. It means no parseable Go package exists in the target directory.

Solutions

Verify the directory path contains at least one valid .go file
Run ls <dir>/*.go to confirm Go sources exist and are non-empty
Fix any parse errors reported in earlier files so detection can succeed
Re-run the bundler from the correct package directory

Example fix

// before: bundler ./assets -> no Go package found in "./assets"
// after: bundler ./internal/app  (directory with package app)

Defensive patterns

Strategy: validation

Validate before calling

matches, _ := filepath.Glob(filepath.Join(dir, "*.go"))
if len(matches) == 0 {
    return fmt.Errorf("%s has no Go files; not a bundle target", dir)
}

Try / catch

if err := bundle(dir); err != nil && strings.Contains(err.Error(), "no Go package found") {
    // correct the path or build a minimal package first
}

Prevention

Confirm the target directory contains *.go files before bundling
Run `go list ./...` to validate package paths
Use paths relative to the module root to avoid pointing at asset dirs

When it happens

Trigger: The directory passed to the bundler contains no .go files at all, or every .go file failed to parse earlier in the loop (leaving packageName empty at the end).

Common situations: Pointing the bundler at the wrong path (e.g. an assets or docs directory); an empty freshly created package directory; all sources hidden by the walk's skip rules.

Related errors

AI-assisted analysis of github/copilot-sdk@cd8cf15dc3 (2026-09-09). Data as JSON: /api/errors/36fac7506d8dc18b. Report an issue: GitHub.

Appendix: source

Thrown at go/cmd/bundler/main.go:256

		}

		path := filepath.Join(dir, name)
		file, err := parser.ParseFile(token.NewFileSet(), path, nil, parser.PackageClauseOnly)
		if err != nil {
			return defaultPackageName, fmt.Errorf("failed to parse package clause in %q: %w", path, err)
		}

		if packageName == "" {
			packageName = file.Name.Name
			continue
		}
		if packageName != file.Name.Name {
			return defaultPackageName, fmt.Errorf("multiple packages %q and %q found in %q", packageName, file.Name.Name, dir)
		}
	}

	if packageName == "" {
		return defaultPackageName, fmt.Errorf("no Go package found in %q", dir)
	}
	return packageName, nil
}

// detectCLIVersion detects the CLI version by:
// 1. Running "go list -m" to get the copilot-sdk version from the user's go.mod
// 2. Fetching package.json from the SDK repo at that version
// 3. Extracting the pinned Copilot CLI version from it
func detectCLIVersion() (string, error) {
	// Get the SDK version from the user's go.mod
	sdkVersion, err := getSDKVersion()
	if err != nil {
		return "", fmt.Errorf("failed to get SDK version: %w", err)
	}

	fmt.Printf("Found copilot-sdk %s in go.mod\n", sdkVersion)

	// Fetch package.json from the SDK repo at that version

View on GitHub (pinned to cd8cf15dc3)