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go.sentinel_error_comparison

Correctness Medium

Detects error comparisons using == or string matching instead of errors.Is().

Why It Matters

Direct error comparison:

Misses wrapped errors — fmt.Errorf("%w", err) won’t match
Breaks error chains — Go 1.13+ error wrapping is ignored
Fragile — String comparisons break on message changes

Example

// ❌ Before (broken with wrapped errors)
if err == sql.ErrNoRows {
    return nil
}

if err.Error() == "not found" {
    return nil
}

// ✅ After (handles wrapped errors)
if errors.Is(err, sql.ErrNoRows) {
    return nil
}

What Unfault Detects

err == sentinel comparisons
err.Error() == "..." string comparisons
Missing errors.Is() usage

Auto-Fix

Unfault replaces direct comparison with errors.Is():

if errors.Is(err, sql.ErrNoRows) {
    // ...
}