From 965644b0fee3f2977d83b12ea96eac24b8d7359c Mon Sep 17 00:00:00 2001 From: Steve Yegge Date: Mon, 22 Dec 2025 00:05:46 -0800 Subject: [PATCH] Add identity collision prevention, detection, and correction (gt-xp2s) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - internal/lock: New package with PID-based lockfiles for worker identity - gt prime: Acquire identity lock for crew/polecat roles, fail on collision - gt agents check: Detect stale locks and identity collisions - gt agents fix: Clean up stale locks - gt doctor: New identity-collision check with --fix support 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude --- internal/cmd/agents.go | 242 +++++++++++++++++++++++- internal/cmd/doctor.go | 1 + internal/cmd/prime.go | 58 ++++++ internal/doctor/identity_check.go | 136 ++++++++++++++ internal/lock/lock.go | 298 ++++++++++++++++++++++++++++++ 5 files changed, 734 insertions(+), 1 deletion(-) create mode 100644 internal/doctor/identity_check.go create mode 100644 internal/lock/lock.go diff --git a/internal/cmd/agents.go b/internal/cmd/agents.go index 30ccad2c..c4757b4e 100644 --- a/internal/cmd/agents.go +++ b/internal/cmd/agents.go @@ -1,14 +1,19 @@ package cmd import ( + "encoding/json" "fmt" "os" "os/exec" + "path/filepath" "sort" "strings" "github.com/spf13/cobra" + "github.com/steveyegge/gastown/internal/lock" + "github.com/steveyegge/gastown/internal/style" "github.com/steveyegge/gastown/internal/tmux" + "github.com/steveyegge/gastown/internal/workspace" ) // AgentType represents the type of Gas Town agent. @@ -71,11 +76,49 @@ var agentsListCmd = &cobra.Command{ RunE: runAgentsList, } -var agentsAllFlag bool +var agentsCheckCmd = &cobra.Command{ + Use: "check", + Short: "Check for identity collisions and stale locks", + Long: `Check for identity collisions and stale locks. + +This command helps detect situations where multiple Claude processes +think they own the same worker identity. + +Output shows: + - Active tmux sessions with gt- prefix + - Identity locks in worker directories + - Collisions (multiple agents claiming same identity) + - Stale locks (dead PIDs)`, + RunE: runAgentsCheck, +} + +var agentsFixCmd = &cobra.Command{ + Use: "fix", + Short: "Fix identity collisions and clean up stale locks", + Long: `Clean up identity collisions and stale locks. + +This command: + 1. Removes stale locks (where the PID is dead) + 2. Reports collisions that need manual intervention + +For collisions with live processes, you must manually: + - Kill the duplicate session, OR + - Decide which agent should own the identity`, + RunE: runAgentsFix, +} + +var ( + agentsAllFlag bool + agentsCheckJSON bool +) func init() { agentsCmd.PersistentFlags().BoolVarP(&agentsAllFlag, "all", "a", false, "Include polecats in the menu") + agentsCheckCmd.Flags().BoolVar(&agentsCheckJSON, "json", false, "Output as JSON") + agentsCmd.AddCommand(agentsListCmd) + agentsCmd.AddCommand(agentsCheckCmd) + agentsCmd.AddCommand(agentsFixCmd) rootCmd.AddCommand(agentsCmd) } @@ -333,3 +376,200 @@ func runAgentsList(cmd *cobra.Command, args []string) error { return nil } + +// CollisionReport holds the results of a collision check. +type CollisionReport struct { + TotalSessions int `json:"total_sessions"` + TotalLocks int `json:"total_locks"` + Collisions int `json:"collisions"` + StaleLocks int `json:"stale_locks"` + Issues []CollisionIssue `json:"issues,omitempty"` + Locks map[string]*lock.LockInfo `json:"locks,omitempty"` +} + +// CollisionIssue describes a single collision or lock issue. +type CollisionIssue struct { + Type string `json:"type"` // "stale", "collision", "orphaned" + WorkerDir string `json:"worker_dir"` + Message string `json:"message"` + PID int `json:"pid,omitempty"` + SessionID string `json:"session_id,omitempty"` +} + +func runAgentsCheck(cmd *cobra.Command, args []string) error { + townRoot, err := workspace.FindFromCwdOrError() + if err != nil { + return fmt.Errorf("not in a Gas Town workspace: %w", err) + } + + report, err := buildCollisionReport(townRoot) + if err != nil { + return err + } + + if agentsCheckJSON { + enc := json.NewEncoder(os.Stdout) + enc.SetIndent("", " ") + return enc.Encode(report) + } + + // Text output + if len(report.Issues) == 0 { + fmt.Printf("%s All agents healthy\n", style.Bold.Render("✓")) + fmt.Printf(" Sessions: %d, Locks: %d\n", report.TotalSessions, report.TotalLocks) + return nil + } + + fmt.Printf("%s\n\n", style.Bold.Render("⚠️ Issues Detected")) + fmt.Printf("Collisions: %d, Stale locks: %d\n\n", report.Collisions, report.StaleLocks) + + for _, issue := range report.Issues { + fmt.Printf("%s %s\n", style.Bold.Render("!"), issue.Message) + fmt.Printf(" Dir: %s\n", issue.WorkerDir) + if issue.PID > 0 { + fmt.Printf(" PID: %d\n", issue.PID) + } + fmt.Println() + } + + fmt.Printf("Run %s to fix stale locks\n", style.Dim.Render("gt agents fix")) + + return nil +} + +func runAgentsFix(cmd *cobra.Command, args []string) error { + townRoot, err := workspace.FindFromCwdOrError() + if err != nil { + return fmt.Errorf("not in a Gas Town workspace: %w", err) + } + + // Clean stale locks + cleaned, err := lock.CleanStaleLocks(townRoot) + if err != nil { + return fmt.Errorf("cleaning stale locks: %w", err) + } + + if cleaned > 0 { + fmt.Printf("%s Cleaned %d stale lock(s)\n", style.Bold.Render("✓"), cleaned) + } else { + fmt.Printf("%s No stale locks found\n", style.Dim.Render("○")) + } + + // Check for remaining issues + report, err := buildCollisionReport(townRoot) + if err != nil { + return err + } + + if report.Collisions > 0 { + fmt.Println() + fmt.Printf("%s %d collision(s) require manual intervention:\n\n", + style.Bold.Render("⚠"), report.Collisions) + + for _, issue := range report.Issues { + if issue.Type == "collision" { + fmt.Printf(" %s %s\n", style.Bold.Render("!"), issue.Message) + } + } + + fmt.Println() + fmt.Printf("To fix, close duplicate sessions or remove lock files manually.\n") + } + + return nil +} + +func buildCollisionReport(townRoot string) (*CollisionReport, error) { + report := &CollisionReport{ + Locks: make(map[string]*lock.LockInfo), + } + + // Get all tmux sessions + t := tmux.NewTmux() + sessions, err := t.ListSessions() + if err != nil { + sessions = []string{} // Continue even if tmux not running + } + + // Filter to gt- sessions + var gtSessions []string + for _, s := range sessions { + if strings.HasPrefix(s, "gt-") { + gtSessions = append(gtSessions, s) + } + } + report.TotalSessions = len(gtSessions) + + // Find all locks + locks, err := lock.FindAllLocks(townRoot) + if err != nil { + return nil, fmt.Errorf("finding locks: %w", err) + } + report.TotalLocks = len(locks) + report.Locks = locks + + // Check each lock for issues + for workerDir, lockInfo := range locks { + if lockInfo.IsStale() { + report.StaleLocks++ + report.Issues = append(report.Issues, CollisionIssue{ + Type: "stale", + WorkerDir: workerDir, + Message: fmt.Sprintf("Stale lock (dead PID %d)", lockInfo.PID), + PID: lockInfo.PID, + SessionID: lockInfo.SessionID, + }) + continue + } + + // Check if the locked session exists in tmux + expectedSession := guessSessionFromWorkerDir(workerDir, townRoot) + if expectedSession != "" { + found := false + for _, s := range gtSessions { + if s == expectedSession { + found = true + break + } + } + if !found { + // Lock exists but session doesn't - potential orphan or collision + report.Collisions++ + report.Issues = append(report.Issues, CollisionIssue{ + Type: "orphaned", + WorkerDir: workerDir, + Message: fmt.Sprintf("Lock exists (PID %d) but no tmux session '%s'", lockInfo.PID, expectedSession), + PID: lockInfo.PID, + SessionID: lockInfo.SessionID, + }) + } + } + } + + return report, nil +} + +func guessSessionFromWorkerDir(workerDir, townRoot string) string { + relPath, err := filepath.Rel(townRoot, workerDir) + if err != nil { + return "" + } + + parts := strings.Split(filepath.ToSlash(relPath), "/") + if len(parts) < 3 { + return "" + } + + rig := parts[0] + workerType := parts[1] + workerName := parts[2] + + switch workerType { + case "crew": + return fmt.Sprintf("gt-%s-crew-%s", rig, workerName) + case "polecats": + return fmt.Sprintf("gt-%s-%s", rig, workerName) + } + + return "" +} diff --git a/internal/cmd/doctor.go b/internal/cmd/doctor.go index ec51148e..89c7d143 100644 --- a/internal/cmd/doctor.go +++ b/internal/cmd/doctor.go @@ -60,6 +60,7 @@ func runDoctor(cmd *cobra.Command, args []string) error { d.Register(doctor.NewOrphanProcessCheck()) d.Register(doctor.NewBranchCheck()) d.Register(doctor.NewBeadsSyncOrphanCheck()) + d.Register(doctor.NewIdentityCollisionCheck()) // Ephemeral beads checks d.Register(doctor.NewEphemeralExistsCheck()) diff --git a/internal/cmd/prime.go b/internal/cmd/prime.go index 4c1a5cfd..9e3a83e1 100644 --- a/internal/cmd/prime.go +++ b/internal/cmd/prime.go @@ -2,6 +2,7 @@ package cmd import ( "bytes" + "errors" "fmt" "os" "os/exec" @@ -10,6 +11,7 @@ import ( "github.com/spf13/cobra" "github.com/steveyegge/gastown/internal/beads" + "github.com/steveyegge/gastown/internal/lock" "github.com/steveyegge/gastown/internal/style" "github.com/steveyegge/gastown/internal/templates" "github.com/steveyegge/gastown/internal/workspace" @@ -74,6 +76,11 @@ func runPrime(cmd *cobra.Command, args []string) error { // Detect role ctx := detectRole(cwd, townRoot) + // Check and acquire identity lock for worker roles + if err := acquireIdentityLock(ctx); err != nil { + return err + } + // Ensure beads redirect exists for worktree-based roles ensureBeadsRedirect(ctx) @@ -668,6 +675,57 @@ func outputDeaconPatrolContext(ctx RoleContext) { fmt.Println(" gt mol bond mol-deacon-patrol") } +// acquireIdentityLock checks and acquires the identity lock for worker roles. +// This prevents multiple agents from claiming the same worker identity. +// Returns an error if another agent already owns this identity. +func acquireIdentityLock(ctx RoleContext) error { + // Only lock worker roles (polecat, crew) + // Infrastructure roles (mayor, witness, refinery, deacon) are singletons + // managed by tmux session names, so they don't need file-based locks + if ctx.Role != RolePolecat && ctx.Role != RoleCrew { + return nil + } + + // Create lock for this worker directory + l := lock.New(ctx.WorkDir) + + // Determine session ID from environment or context + sessionID := os.Getenv("TMUX_PANE") + if sessionID == "" { + // Fall back to a descriptive identifier + sessionID = fmt.Sprintf("%s/%s", ctx.Rig, ctx.Polecat) + } + + // Try to acquire the lock + if err := l.Acquire(sessionID); err != nil { + if errors.Is(err, lock.ErrLocked) { + // Another agent owns this identity + fmt.Printf("\n%s\n\n", style.Bold.Render("⚠️ IDENTITY COLLISION DETECTED")) + fmt.Printf("Another agent already claims this worker identity.\n\n") + + // Show lock details + if info, readErr := l.Read(); readErr == nil { + fmt.Printf("Lock holder:\n") + fmt.Printf(" PID: %d\n", info.PID) + fmt.Printf(" Session: %s\n", info.SessionID) + fmt.Printf(" Acquired: %s\n", info.AcquiredAt.Format("2006-01-02 15:04:05")) + fmt.Println() + } + + fmt.Printf("To resolve:\n") + fmt.Printf(" 1. Find the other session and close it, OR\n") + fmt.Printf(" 2. Run: gt doctor --fix (cleans stale locks)\n") + fmt.Printf(" 3. If lock is stale: rm %s/.gastown/agent.lock\n", ctx.WorkDir) + fmt.Println() + + return fmt.Errorf("cannot claim identity %s/%s: %w", ctx.Rig, ctx.Polecat, err) + } + return fmt.Errorf("acquiring identity lock: %w", err) + } + + return nil +} + // ensureBeadsRedirect ensures the .beads/redirect file exists for worktree-based roles. // This handles cases where git clean or other operations delete the redirect file. func ensureBeadsRedirect(ctx RoleContext) { diff --git a/internal/doctor/identity_check.go b/internal/doctor/identity_check.go new file mode 100644 index 00000000..5eb58b7a --- /dev/null +++ b/internal/doctor/identity_check.go @@ -0,0 +1,136 @@ +package doctor + +import ( + "fmt" + "strings" + + "github.com/steveyegge/gastown/internal/lock" + "github.com/steveyegge/gastown/internal/tmux" +) + +// IdentityCollisionCheck checks for agent identity collisions and stale locks. +type IdentityCollisionCheck struct{} + +// NewIdentityCollisionCheck creates a new identity collision check. +func NewIdentityCollisionCheck() *IdentityCollisionCheck { + return &IdentityCollisionCheck{} +} + +func (c *IdentityCollisionCheck) Name() string { + return "identity-collision" +} + +func (c *IdentityCollisionCheck) Description() string { + return "Check for agent identity collisions and stale locks" +} + +func (c *IdentityCollisionCheck) CanFix() bool { + return true // Can fix stale locks +} + +func (c *IdentityCollisionCheck) Run(ctx *CheckContext) *CheckResult { + // Find all locks + locks, err := lock.FindAllLocks(ctx.TownRoot) + if err != nil { + return &CheckResult{ + Name: c.Name(), + Status: StatusWarning, + Message: fmt.Sprintf("could not scan for locks: %v", err), + } + } + + if len(locks) == 0 { + return &CheckResult{ + Name: c.Name(), + Status: StatusOK, + Message: "no worker locks found", + } + } + + // Get active tmux sessions for cross-reference + t := tmux.NewTmux() + sessions, _ := t.ListSessions() // Ignore errors - might not have tmux + + sessionSet := make(map[string]bool) + for _, s := range sessions { + sessionSet[s] = true + } + + var staleLocks []string + var orphanedLocks []string + var healthyLocks int + + for workerDir, info := range locks { + if info.IsStale() { + staleLocks = append(staleLocks, + fmt.Sprintf("%s (dead PID %d)", workerDir, info.PID)) + continue + } + + // Check if session exists + if info.SessionID != "" && !sessionSet[info.SessionID] { + // Lock has session ID but session doesn't exist + // This could be a collision or orphan + orphanedLocks = append(orphanedLocks, + fmt.Sprintf("%s (PID %d, missing session %s)", workerDir, info.PID, info.SessionID)) + continue + } + + healthyLocks++ + } + + // Build result + if len(staleLocks) == 0 && len(orphanedLocks) == 0 { + return &CheckResult{ + Name: c.Name(), + Status: StatusOK, + Message: fmt.Sprintf("%d worker lock(s), all healthy", healthyLocks), + } + } + + result := &CheckResult{ + Name: c.Name(), + } + + if len(staleLocks) > 0 { + result.Status = StatusWarning + result.Message = fmt.Sprintf("%d stale lock(s) found", len(staleLocks)) + result.Details = append(result.Details, "Stale locks (dead PIDs):") + for _, s := range staleLocks { + result.Details = append(result.Details, " "+s) + } + result.FixHint = "Run 'gt doctor --fix' or 'gt agents fix' to clean up" + } + + if len(orphanedLocks) > 0 { + if result.Status != StatusWarning { + result.Status = StatusWarning + } + if result.Message != "" { + result.Message += ", " + } + result.Message += fmt.Sprintf("%d orphaned lock(s)", len(orphanedLocks)) + result.Details = append(result.Details, "Orphaned locks (missing sessions):") + for _, s := range orphanedLocks { + result.Details = append(result.Details, " "+s) + } + if !strings.Contains(result.FixHint, "doctor") { + result.FixHint = "Run 'gt doctor --fix' to clean up stale locks" + } + } + + return result +} + +func (c *IdentityCollisionCheck) Fix(ctx *CheckContext) error { + cleaned, err := lock.CleanStaleLocks(ctx.TownRoot) + if err != nil { + return fmt.Errorf("cleaning stale locks: %w", err) + } + + if cleaned > 0 { + fmt.Printf(" Cleaned %d stale lock(s)\n", cleaned) + } + + return nil +} diff --git a/internal/lock/lock.go b/internal/lock/lock.go new file mode 100644 index 00000000..8d51a2e3 --- /dev/null +++ b/internal/lock/lock.go @@ -0,0 +1,298 @@ +// Package lock provides agent identity locking to prevent multiple agents +// from claiming the same worker identity. +// +// Lock files are stored at /.gastown/agent.lock and contain: +// - PID of the owning process +// - Timestamp when lock was acquired +// - Session ID (tmux session name) +// +// Stale locks (where the PID is dead) are automatically cleaned up. +package lock + +import ( + "encoding/json" + "errors" + "fmt" + "os" + "path/filepath" + "syscall" + "time" +) + +// Common errors +var ( + ErrLocked = errors.New("worker is locked by another agent") + ErrNotLocked = errors.New("worker is not locked") + ErrStaleLock = errors.New("stale lock detected") + ErrInvalidLock = errors.New("invalid lock file") +) + +// LockInfo contains information about who holds a lock. +type LockInfo struct { + PID int `json:"pid"` + AcquiredAt time.Time `json:"acquired_at"` + SessionID string `json:"session_id,omitempty"` + Hostname string `json:"hostname,omitempty"` +} + +// IsStale checks if the lock is stale (owning process is dead). +func (l *LockInfo) IsStale() bool { + return !processExists(l.PID) +} + +// Lock represents an agent identity lock for a worker directory. +type Lock struct { + workerDir string + lockPath string +} + +// New creates a Lock for the given worker directory. +func New(workerDir string) *Lock { + return &Lock{ + workerDir: workerDir, + lockPath: filepath.Join(workerDir, ".gastown", "agent.lock"), + } +} + +// Acquire attempts to acquire the lock for this worker. +// Returns ErrLocked if another live process holds the lock. +// Automatically cleans up stale locks. +func (l *Lock) Acquire(sessionID string) error { + // Check for existing lock + info, err := l.Read() + if err == nil { + // Lock exists - check if stale + if info.IsStale() { + // Stale lock - remove it + if err := l.Release(); err != nil { + return fmt.Errorf("removing stale lock: %w", err) + } + } else { + // Active lock - check if it's us + if info.PID == os.Getpid() { + // We already hold it - refresh + return l.write(sessionID) + } + // Another process holds it + return fmt.Errorf("%w: PID %d (session: %s, acquired: %s)", + ErrLocked, info.PID, info.SessionID, info.AcquiredAt.Format(time.RFC3339)) + } + } + + // No lock or stale lock removed - acquire it + return l.write(sessionID) +} + +// Release releases the lock if we hold it. +func (l *Lock) Release() error { + if err := os.Remove(l.lockPath); err != nil && !os.IsNotExist(err) { + return fmt.Errorf("removing lock file: %w", err) + } + return nil +} + +// Read reads the current lock info without modifying it. +func (l *Lock) Read() (*LockInfo, error) { + data, err := os.ReadFile(l.lockPath) + if err != nil { + if os.IsNotExist(err) { + return nil, ErrNotLocked + } + return nil, fmt.Errorf("reading lock file: %w", err) + } + + var info LockInfo + if err := json.Unmarshal(data, &info); err != nil { + return nil, fmt.Errorf("%w: %v", ErrInvalidLock, err) + } + + return &info, nil +} + +// Check checks if the worker is locked by another agent. +// Returns nil if unlocked or locked by us. +// Returns ErrLocked if locked by another live process. +// Automatically cleans up stale locks. +func (l *Lock) Check() error { + info, err := l.Read() + if err != nil { + if errors.Is(err, ErrNotLocked) { + return nil // Not locked + } + return err + } + + // Check if stale + if info.IsStale() { + // Clean up stale lock + _ = l.Release() + return nil + } + + // Check if it's us + if info.PID == os.Getpid() { + return nil + } + + // Locked by another process + return fmt.Errorf("%w: PID %d (session: %s)", ErrLocked, info.PID, info.SessionID) +} + +// Status returns a human-readable status of the lock. +func (l *Lock) Status() string { + info, err := l.Read() + if err != nil { + if errors.Is(err, ErrNotLocked) { + return "unlocked" + } + return fmt.Sprintf("error: %v", err) + } + + if info.IsStale() { + return fmt.Sprintf("stale (dead PID %d)", info.PID) + } + + if info.PID == os.Getpid() { + return "locked (by us)" + } + + return fmt.Sprintf("locked by PID %d (session: %s)", info.PID, info.SessionID) +} + +// ForceRelease removes the lock regardless of who holds it. +// Use with caution - only for doctor --fix scenarios. +func (l *Lock) ForceRelease() error { + return l.Release() +} + +// write creates or updates the lock file. +func (l *Lock) write(sessionID string) error { + // Ensure .gastown directory exists + dir := filepath.Dir(l.lockPath) + if err := os.MkdirAll(dir, 0755); err != nil { + return fmt.Errorf("creating lock directory: %w", err) + } + + hostname, _ := os.Hostname() + info := LockInfo{ + PID: os.Getpid(), + AcquiredAt: time.Now(), + SessionID: sessionID, + Hostname: hostname, + } + + data, err := json.MarshalIndent(info, "", " ") + if err != nil { + return fmt.Errorf("marshaling lock info: %w", err) + } + + if err := os.WriteFile(l.lockPath, data, 0644); err != nil { + return fmt.Errorf("writing lock file: %w", err) + } + + return nil +} + +// processExists checks if a process with the given PID exists and is alive. +func processExists(pid int) bool { + if pid <= 0 { + return false + } + + // On Unix, sending signal 0 checks if process exists without affecting it + process, err := os.FindProcess(pid) + if err != nil { + return false + } + + // Try to send signal 0 - this will fail if process doesn't exist + err = process.Signal(syscall.Signal(0)) + return err == nil +} + +// FindAllLocks scans a directory tree for agent.lock files. +// Returns a map of worker directory -> LockInfo. +func FindAllLocks(root string) (map[string]*LockInfo, error) { + locks := make(map[string]*LockInfo) + + err := filepath.Walk(root, func(path string, info os.FileInfo, err error) error { + if err != nil { + return nil // Skip errors + } + + if info.IsDir() { + return nil + } + + if filepath.Base(path) == "agent.lock" && filepath.Base(filepath.Dir(path)) == ".gastown" { + workerDir := filepath.Dir(filepath.Dir(path)) + lock := New(workerDir) + lockInfo, err := lock.Read() + if err == nil { + locks[workerDir] = lockInfo + } + } + + return nil + }) + + return locks, err +} + +// CleanStaleLocks removes all stale locks in a directory tree. +// Returns the number of stale locks cleaned. +func CleanStaleLocks(root string) (int, error) { + locks, err := FindAllLocks(root) + if err != nil { + return 0, err + } + + cleaned := 0 + for workerDir, info := range locks { + if info.IsStale() { + lock := New(workerDir) + if err := lock.Release(); err == nil { + cleaned++ + } + } + } + + return cleaned, nil +} + +// DetectCollisions finds workers with multiple agents claiming the same identity. +// This detects the case where multiple processes think they own the same worker +// by comparing tmux sessions with lock files. +// Returns a list of collision descriptions. +func DetectCollisions(root string, activeSessions []string) []string { + var collisions []string + + locks, err := FindAllLocks(root) + if err != nil { + return collisions + } + + // Build set of active sessions + activeSet := make(map[string]bool) + for _, s := range activeSessions { + activeSet[s] = true + } + + for workerDir, info := range locks { + if info.IsStale() { + collisions = append(collisions, + fmt.Sprintf("stale lock in %s (dead PID %d, session: %s)", + workerDir, info.PID, info.SessionID)) + continue + } + + // Check if the session in the lock matches an active session + if info.SessionID != "" && !activeSet[info.SessionID] { + collisions = append(collisions, + fmt.Sprintf("orphaned lock in %s (session %s not found, PID %d still alive)", + workerDir, info.SessionID, info.PID)) + } + } + + return collisions +}