[duplicate-code] Duplicate Code Pattern: DIFC Agent Tag Add/Drop Operations #1720
Description
🔍 Duplicate Code Pattern: DIFC Agent Tag Operations
Part of duplicate code analysis: #1719
Summary
Three nearly identical methods in internal/difc/agent.go implement the same lock/log/mutate pattern with only the label field and action verb changing. This is security-critical code in the DIFC subsystem where a divergence between these copies (e.g., forgetting to unlock or using the wrong label) could cause data integrity issues.
Duplication Details
Pattern: Lock + Log + Mutate Tag
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Severity: High
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Occurrences: 3 instances
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Locations:
internal/difc/agent.go(lines ~42–49) —AddSecrecyTaginternal/difc/agent.go(lines ~51–58) —AddIntegrityTaginternal/difc/agent.go(lines ~60–67) —DropIntegrityTag
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Code Sample:
// Instance 1
func (a *AgentLabels) AddSecrecyTag(tag Tag) {
logAgent.Printf("Agent %s adding secrecy tag: %s", a.AgentID, tag)
a.mu.Lock()
defer a.mu.Unlock()
a.Secrecy.Label.Add(tag)
log.Printf("[DIFC] Agent %s gained secrecy tag: %s", a.AgentID, tag)
}
// Instance 2 (identical structure, different label)
func (a *AgentLabels) AddIntegrityTag(tag Tag) {
logAgent.Printf("Agent %s adding integrity tag: %s", a.AgentID, tag)
a.mu.Lock()
defer a.mu.Unlock()
a.Integrity.Label.Add(tag)
log.Printf("[DIFC] Agent %s gained integrity tag: %s", a.AgentID, tag)
}
// Instance 3 (identical structure, Remove instead of Add)
func (a *AgentLabels) DropIntegrityTag(tag Tag) {
logAgent.Printf("Agent %s dropping integrity tag: %s", a.AgentID, tag)
a.mu.Lock()
defer a.mu.Unlock()
a.Integrity.Label.Remove(tag)
log.Printf("[DIFC] Agent %s dropped integrity tag: %s", a.AgentID, tag)
}Impact Analysis
- Maintainability: Any change to the locking or logging pattern must be applied to all 3 functions manually — prone to drift
- Bug Risk: If a fourth tag operation is added, the pattern may not be followed exactly
- Code Bloat: 24 lines could be reduced to ~10 lines with a helper
Refactoring Recommendations
- Extract a private
modifyTaghelperOr use a function value for the mutation operation.func (a *AgentLabels) modifyTag(label *Label, tag Tag, action string) { logAgent.Printf("Agent %s %s tag: %s", a.AgentID, action, tag) a.mu.Lock() defer a.mu.Unlock() if action == "dropping" { label.Remove(tag) log.Printf("[DIFC] Agent %s dropped tag: %s", a.AgentID, tag) } else { label.Add(tag) log.Printf("[DIFC] Agent %s gained tag: %s", a.AgentID, tag) } }
- Estimated effort: 30 minutes
- Benefits: Single place to adjust locking strategy, logging format, or add metrics
Implementation Checklist
- Review duplication findings in
internal/difc/agent.go - Design
modifyTagor similar private helper - Refactor the 3 public methods to delegate to helper
- Verify unit tests still pass (
make test-unit) - Verify no DIFC behavior changes
Parent Issue
See parent analysis report: #1719
Related to #1719
Generated by Duplicate Code Detector · ◷
- expires on Mar 17, 2026, 2:56 AM UTC