Return errors explicitly

Functions should return errors explicitly to callers rather than terminating the program, hiding errors in boolean returns, or using implicit error handling. This allows higher-level code to make appropriate decisions about error handling, recovery, and program flow.

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Prompt

Reviewer Prompt
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Functions should return errors explicitly to callers rather than terminating the program, hiding errors in boolean returns, or using implicit error handling. This allows higher-level code to make appropriate decisions about error handling, recovery, and program flow.

Key principles:

  1. Avoid fatal calls in library code - Use return fmt.Errorf(...) instead of log.Fatalf() or t.Fatalf()
  2. Return errors alongside other values - Don’t hide error conditions in boolean returns; make them explicit
  3. Make error handling decisions explicit - Avoid implicit defaults that could mask important error conditions

Example of problematic pattern:

func fileExists(filename string) bool {
    _, err := os.Stat(filename)
    if err != nil && !os.IsNotExist(err) {
        log.Warnf("Unexpected error checking file %s: %v", filename, err)
    }
    return err == nil
}

func initBpfObjects() {
    if err := os.Mkdir(MapsPinpath, os.ModePerm); err != nil {
        log.Fatalf("unable to create ambient bpf mount directory: %v", err)
    }
}

Improved pattern:

func fileExists(filename string) (bool, error) {
    if filename == "" {
        return false, nil
    }
    _, err := os.Stat(filename)
    if err != nil && !os.IsNotExist(err) {
        return false, fmt.Errorf("unexpected error checking file %s: %v", filename, err)
    }
    return err == nil, nil
}

func initBpfObjects() error {
    if err := os.Mkdir(MapsPinpath, os.ModePerm); err != nil {
        return fmt.Errorf("unable to create ambient bpf mount directory: %v", err)
    }
    return nil
}

This approach provides callers with the flexibility to implement appropriate error handling strategies, retry logic, or graceful degradation based on their specific context and requirements.

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