wavetermdev/waveterm · error

file is not a Go file: %s

Error message

file is not a Go file: %s

What it means

FormatGoFile only formats Go source; after resolving the file path inside the app directory it checks filepath.Ext(filePath) == ".go". If the requested file has any other extension, it returns "file is not a Go file" with the original fileName. This guards gofmt from being run on non-Go files.

Source

Thrown at pkg/waveappstore/waveappstore.go:425

}

func FormatGoFile(appId string, fileName string) error {
	if err := ValidateAppId(appId); err != nil {
		return fmt.Errorf("invalid appId: %w", err)
	}

	appDir, err := GetAppDir(appId)
	if err != nil {
		return err
	}

	filePath, err := validateAndResolveFilePath(appDir, fileName)
	if err != nil {
		return err
	}

	if filepath.Ext(filePath) != ".go" {
		return fmt.Errorf("file is not a Go file: %s", fileName)
	}

	gofmtPath, err := waveapputil.ResolveGoFmtPath()
	if err != nil {
		return fmt.Errorf("failed to resolve gofmt path: %w", err)
	}

	cmd := exec.Command(gofmtPath, "-w", filePath)
	if output, err := cmd.CombinedOutput(); err != nil {
		return fmt.Errorf("gofmt failed: %w\nOutput: %s", err, string(output))
	}

	return nil
}

func ListAllAppFiles(appId string) (*fileutil.ReadDirResult, error) {
	if err := ValidateAppId(appId); err != nil {
		return nil, fmt.Errorf("invalid appId: %w", err)

View on GitHub (pinned to a4447c1563)

Solutions

1. Only call FormatGoFile for files ending in ".go"; route other file types to their own formatters (prettier, etc.)
2. Check strings.HasSuffix(fileName, ".go") in the caller before invoking
3. If the file genuinely is Go source, rename it to have a .go extension first (RenameAppFile)
4. Handle the error gracefully in UI by disabling the format action for non-Go files

Example fix

// before
FormatGoFile(appId, fileName)
// after
if strings.HasSuffix(fileName, ".go") {
    FormatGoFile(appId, fileName)
}

if !strings.HasSuffix(fileName, ".go") {
	return fmt.Errorf("%s is not a Go file; use the appropriate formatter", fileName)
}

func isGoFile(name string) bool { return strings.HasSuffix(strings.ToLower(name), ".go") }

if err := FormatGoFile(appId, fileName); err != nil {
	if strings.Contains(err.Error(), "file is not a Go file") {
		return nil // skip formatting for non-Go files
	}
	return err
}

When it happens

Trigger: Calling FormatGoFile on e.g. "manifest.json", "index.tsx", "style.css", or any file without a ".go" extension within the app directory.

Common situations: A generic "format this file" frontend action routed to the Go formatter regardless of file type; user opens a README and hits format; case-sensitivity issue where the file is named "MAIN.GO" — actually .GO uppercase also fails since Ext comparison is case-sensitive on Linux.

Related errors

• Image too large (>5MB)
• Unsupported or invalid image type: ${blob.type}
• Invalid CSS color: ${String(color)}
• Invalid CSS color: ${color}
• ai:model is required

AI-assisted analysis of wavetermdev/waveterm@a4447c1563 (2026-09-01). Data as JSON: /api/errors/5fa35397796c21af. Report an issue: GitHub.