[duplicate-code] Duplicate Code Pattern: Config Finalization Pipeline (TOML vs JSON Stdin Paths)

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🔍 Duplicate Code Pattern: Config Finalization Pipeline (TOML vs JSON Stdin Paths)

Part of duplicate code analysis: #3560

Summary

Both LoadFromFile (TOML path, config_core.go) and convertStdinConfig (JSON stdin path, config_stdin.go) execute nearly identical post-parse finalization steps: validate trusted bots, apply gateway defaults, apply feature defaults, and validate guard policies. This shared pipeline is inlined in both functions rather than extracted into a reusable helper.

Duplication Details

Pattern: Repeated config finalization sequence

• Severity: Low
• Occurrences: 2 locations
• Locations:
  • internal/config/config_core.go (lines 364–403) — TOML path, LoadFromFile
  • internal/config/config_stdin.go (lines 316–360) — JSON stdin path, convertStdinConfig

config_core.go (TOML path):

// Initialize gateway if not present
if cfg.Gateway == nil {
    cfg.Gateway = &GatewayConfig{}
}
if err := validateTrustedBots(cfg.Gateway.TrustedBots); err != nil {
    return nil, err
}
// ... opentelemetry merge ...
applyGatewayDefaults(cfg.Gateway)
applyDefaults(&cfg)
if cfg.Gateway.PayloadSizeThreshold < 0 {
    return nil, fmt.Errorf("gateway.payload_size_threshold must be a positive integer, ...")
}
if err := validateGuardPolicies(&cfg); err != nil {
    return nil, err
}

config_stdin.go (JSON stdin path):

if stdinCfg.Gateway != nil {
    // ...
    if stdinCfg.Gateway.TrustedBots != nil {
        if err := validateTrustedBots(stdinCfg.Gateway.TrustedBots); err != nil {
            return nil, err
        }
        // ...
    }
    applyGatewayDefaults(cfg.Gateway)
} else {
    cfg.Gateway = &GatewayConfig{}
    applyGatewayDefaults(cfg.Gateway)
}
applyDefaults(cfg)
// ...
if err := validateGuardPolicies(cfg); err != nil {
    return nil, err
}

Steps shared across both paths: validateTrustedBots → applyGatewayDefaults → applyDefaults → validateGuardPolicies

Impact Analysis

• Maintainability: Adding a new post-parse validation step (like PayloadSizeThreshold was added to TOML) requires updating both code paths. The PayloadSizeThreshold < 0 check already exists only in LoadFromFile and not in convertStdinConfig, suggesting drift has begun.
• Bug Risk: Low for now, but finalization step drift between config paths could cause subtle behavior differences (e.g., a validation present on TOML path but missing from JSON stdin path, as was the case with this commit's auth fix).
• Code Bloat: ~15 lines of shared finalization logic scattered across two functions.

Refactoring Recommendations

1. Extract finalizeConfig(cfg *Config) error

   • Place in: internal/config/config_core.go or a new internal/config/config_finalize.go
   • Encapsulates: validateTrustedBots, applyGatewayDefaults, applyDefaults, PayloadSizeThreshold validation, validateGuardPolicies
   • Both LoadFromFile and convertStdinConfig call this helper after their path-specific parsing
   • Estimated effort: 2–3 hours
   • Benefits: Single place to add/modify finalization steps, prevents future drift between config paths

2. Lower priority than pattern 1 — This is latent structural duplication; the immediate risk is low. Consider tackling during a broader config refactor.

Implementation Checklist

• Identify all finalization steps common to both paths
• Extract finalizeConfig(cfg *Config) error helper
• Update LoadFromFile and convertStdinConfig to call the helper
• Verify PayloadSizeThreshold validation is included in the shared helper
• Run make test-all to verify no regressions

Parent Issue

See parent analysis report: #3560
Related to #3560

Generated by Duplicate Code Detector · ● 1M · ◷

• expires on Apr 18, 2026, 5:52 AM UTC