fix(batch1): safe fixes — saveOffsets ordering, pid atomic, error handlers, go mutex, frontend cleanup

plugin/server/api.go

@@ -122,6 +122,16 @@ func (p *Plugin) handleCreateSession(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// Validate KV key length — Mattermost enforces a 50-char limit.
+	// Encoded key = kvPrefix (11 chars) + url.PathEscape(sessionKey).
+	// Exceeding the limit causes KVSet to silently succeed but never store data.
+	if len(encodeKey(req.SessionKey)) > 50 {
+		writeJSON(w, http.StatusBadRequest, map[string]string{
+			"error": fmt.Sprintf("session_key too long: encoded key length %d exceeds 50-char KV limit", len(encodeKey(req.SessionKey))),
+		})
+		return
+	}
+
 	// Check max active sessions
 	config := p.getConfiguration()
 	allSessions, _ := p.store.ListAllSessions()

plugin/server/plugin.go

@@ -21,6 +21,9 @@ type Plugin struct {
 	// store wraps KV store operations for session persistence.
 	store *Store
 
+	// botUserIDLock synchronizes access to botUserID.
+	botUserIDLock sync.RWMutex
+
 	// botUserID is the plugin's bot user ID (created on activation).
 	botUserID string
 
@@ -41,7 +44,9 @@ func (p *Plugin) OnActivate() error {
 	if appErr != nil {
 		p.API.LogWarn("Failed to ensure bot user", "error", appErr.Error())
 	} else {
+		p.botUserIDLock.Lock()
 		p.botUserID = botID
+		p.botUserIDLock.Unlock()
 		p.API.LogInfo("Plugin bot user ensured", "botUserID", botID)
 	}
 
@@ -75,8 +80,10 @@ func (p *Plugin) sessionCleanupLoop() {
 	}
 }
 
-// getBotUserID returns the plugin's bot user ID.
+// getBotUserID returns the plugin's bot user ID (thread-safe).
 func (p *Plugin) getBotUserID() string {
+	p.botUserIDLock.RLock()
+	defer p.botUserIDLock.RUnlock()
 	return p.botUserID
 }
 
@@ -93,6 +100,10 @@ func (p *Plugin) OnDeactivate() error {
 		p.API.LogWarn("Failed to list sessions on deactivate", "error", err.Error())
 	} else {
 		for _, s := range sessions {
+			// Skip sessions already in a terminal state — do not overwrite done/error
+			if s.Status == "done" || s.Status == "error" {
+				continue
+			}
 			s.Status = "interrupted"
 			_ = p.store.SaveSession(s.SessionKey, s)
 			p.broadcastUpdate(s.ChannelID, s)

plugin/webapp/src/index.tsx

@@ -61,6 +61,13 @@ class LiveStatusPlugin {
 
       window.__livestatus_updates[data.post_id] = update;
 
+      // Evict completed sessions from the update cache after 60s to prevent unbounded growth
+      if (data.status === 'done' || data.status === 'error' || data.status === 'interrupted') {
+        setTimeout(() => {
+          delete window.__livestatus_updates[data.post_id];
+        }, 60000);
+      }
+
       // Notify post-specific listeners
       const listeners = window.__livestatus_listeners[data.post_id];
       if (listeners) {
@@ -82,7 +89,16 @@ class LiveStatusPlugin {
   }
 
   uninitialize(): void {
-    // Cleanup handled by Mattermost plugin framework
+    // Clear global listener and update stores to prevent accumulation across reloads
+    window.__livestatus_listeners = {};
+    window.__livestatus_updates = {};
+
+    // Unregister the custom post type component if it was registered
+    if (this.postTypeComponentId) {
+      // registry is not available here — Mattermost framework cleans up on deactivate.
+      // Clearing postTypeComponentId prevents stale references.
+      this.postTypeComponentId = null;
+    }
   }
 }
 

src/watcher-manager.js

@@ -47,8 +47,19 @@ if (cmd === 'start') {
 
 // ---- PID File helpers ----
 function writePidFile(pidFile) {
+  try {
     // eslint-disable-next-line security/detect-non-literal-fs-filename
-  fs.writeFileSync(pidFile, String(process.pid), 'utf8');
+    const fd = fs.openSync(pidFile, 'wx');
+    fs.writeSync(fd, String(process.pid));
+    fs.closeSync(fd);
+  } catch (err) {
+    if (err.code === 'EEXIST') {
+      // Another process won the race — bail out
+      console.error('PID file already exists — another daemon may be running');
+      process.exit(1);
+    }
+    throw err;
+  }
 }
 
 function readPidFile(pidFile) {
@@ -100,8 +111,10 @@ function saveOffsets(offsetFile, sessions) {
   try {
     // eslint-disable-next-line security/detect-non-literal-fs-filename
     fs.writeFileSync(offsetFile, JSON.stringify(offsets, null, 2), 'utf8');
-  } catch (_e) {
-    /* ignore write error */
+  } catch (writeErr) {
+    // Log disk-full / permission errors so they are visible in daemon logs
+    // eslint-disable-next-line no-console
+    console.warn('[saveOffsets] Failed to write offset file:', writeErr.message);
   }
 }
 
@@ -115,6 +128,16 @@ async function startDaemon() {
   const config = getConfig();
   const logger = getLogger();
 
+  // Global error handlers — prevent silent daemon death from unhandled rejections
+  process.on('unhandledRejection', (reason) => {
+    logger.error({ reason }, 'Unhandled promise rejection — shutting down');
+    shutdown().finally(() => process.exit(1));
+  });
+  process.on('uncaughtException', (err) => {
+    logger.error({ err }, 'Uncaught exception — shutting down');
+    shutdown().finally(() => process.exit(1));
+  });
+
   // Check if already running
   const existingPid = readPidFile(config.pidFile);
   if (existingPid && isProcessRunning(existingPid)) {
@@ -459,7 +482,7 @@ async function startDaemon() {
 
   // ---- Session Idle (from watcher) ----
   watcher.on('session-idle', async (sessionKey, state) => {
-    const box = activeBoxes.get(sessionKey);
+    const box = activeBoxes.get(sessionKey); // snapshot at entry
     if (!box) {
       // Sub-agent completed
       updateParentWithChild(activeBoxes, watcher, sharedStatusBox, pluginClient, sessionKey, state, logger);
@@ -492,12 +515,23 @@ async function startDaemon() {
       logger.error({ sessionKey, err }, 'Failed to update final status');
     }
 
+    // Guard: if the box was replaced during the awaits above (new session reactivated),
+    // skip cleanup to avoid killing the newly re-added session.
+    if (activeBoxes.get(sessionKey) !== box) {
+      logger.info({ sessionKey }, 'session-idle: box replaced during await — skipping cleanup (new session active)');
+      return;
+    }
+
     // Save to completedBoxes so we can reuse the post ID if the session reactivates
     completedBoxes.set(sessionKey, {
       postId: box.postId,
       lastOffset: state.lastOffset || 0,
     });
 
+    // Persist final offsets BEFORE removing session from watcher so the
+    // completed session's last offset is captured in the snapshot.
+    saveOffsets(config.offsetFile, watcher.sessions);
+
     // Clean up active tracking
     activeBoxes.delete(sessionKey);
     watcher.removeSession(sessionKey);
@@ -505,9 +539,6 @@ async function startDaemon() {
     // ensures we reuse the existing post instead of creating a new one.
     monitor.forgetSession(sessionKey);
     globalMetrics.activeSessions = activeBoxes.size;
-
-    // Persist final offsets
-    saveOffsets(config.offsetFile, watcher.sessions);
   });
 
   // ---- Start all subsystems ----
@@ -534,6 +565,9 @@ async function startDaemon() {
 
     logger.info({ signal }, 'Shutting down gracefully');
 
+    // Persist offsets for all active sessions before stopping the watcher
+    saveOffsets(config.offsetFile, watcher.sessions);
+
     // Stop accepting new sessions
     monitor.stop();
     watcher.stop();