Disposable Not Disposed (ARCH5080)

Key go.performance.disposable-not-disposed · Severity error · Category performance

A resource with a Close method that is created but never released leaks. Use defer x.Close() right after creating it.

Incorrect

func read(path string) ([]byte, error) {
  f, err := os.Open(path)
  if err != nil {
    return nil, err
  }
  return io.ReadAll(f)
}

Correct

func read(path string) ([]byte, error) {
  f, err := os.Open(path)
  if err != nil {
    return nil, err
  }
  defer f.Close()
  return io.ReadAll(f)
}

Fix

Add defer x.Close() immediately after creating the resource.