fix(mcp): migrate the last-read fallback on identity rename, purge, and channel rename/delete

mcp_bridge.py

@@ -510,6 +510,11 @@ def migrate_identity(old_name: str, new_name: str):
     with _cursors_lock:
         if old_name in _cursors:
             _cursors[new_name] = _cursors.pop(old_name)
+    with _last_read_lock:
+        if old_name in _last_read_channel:
+            _last_read_channel[new_name] = _last_read_channel.pop(old_name)
+        if old_name in _last_read_job_id:
+            _last_read_job_id[new_name] = _last_read_job_id.pop(old_name)
     if old_name in _roles:
         _roles[new_name] = _roles.pop(old_name)
         _save_roles()
@@ -524,26 +529,37 @@ def purge_identity(name: str):
         _activity_ts.pop(name, None)
     with _cursors_lock:
         _cursors.pop(name, None)
+    with _last_read_lock:
+        _last_read_channel.pop(name, None)
+        _last_read_job_id.pop(name, None)
     if name in _roles:
         del _roles[name]
         _save_roles()
     _save_cursors()
 
 
 def migrate_cursors_rename(old_name: str, new_name: str):
-    """Move cursor entries from old channel name to new channel name."""
+    """Move cursor and fallback entries from old channel to new channel."""
     with _cursors_lock:
         for agent_cursors in _cursors.values():
             if old_name in agent_cursors:
                 agent_cursors[new_name] = agent_cursors.pop(old_name)
+    with _last_read_lock:
+        for sender, fallback in list(_last_read_channel.items()):
+            if fallback == old_name:
+                _last_read_channel[sender] = new_name
     _save_cursors()
 
 
 def migrate_cursors_delete(channel: str):
-    """Remove cursor entries for a deleted channel."""
+    """Remove cursors and reset every stale fallback to #general."""
     with _cursors_lock:
         for agent_cursors in _cursors.values():
             agent_cursors.pop(channel, None)
+    with _last_read_lock:
+        for sender, fallback in list(_last_read_channel.items()):
+            if fallback == channel:
+                _last_read_channel[sender] = "general"
     _save_cursors()
 
 

tests/test_channel_fallback.py

@@ -144,5 +144,54 @@ def test_explicit_channel_is_never_overridden(self):
         self.assertEqual(channel, "portfolio")
 
 
+class ChannelFallbackMigrationTests(unittest.TestCase):
+    """Tests that identity and channel lifecycle hooks keep the fallback
+    maps in sync (rename/purge of agents, rename/delete of channels)."""
+
+    def setUp(self):
+        self._saved_ch = dict(mcp_bridge._last_read_channel)
+        self._saved_job = dict(mcp_bridge._last_read_job_id)
+        mcp_bridge._last_read_channel.clear()
+        mcp_bridge._last_read_job_id.clear()
+
+    def tearDown(self):
+        mcp_bridge._last_read_channel.clear()
+        mcp_bridge._last_read_channel.update(self._saved_ch)
+        mcp_bridge._last_read_job_id.clear()
+        mcp_bridge._last_read_job_id.update(self._saved_job)
+
+    def test_identity_rename_carries_fallback_state(self):
+        mcp_bridge._last_read_channel["alice"] = "bugfixing"
+        mcp_bridge._last_read_job_id["alice"] = 7
+        mcp_bridge.migrate_identity("alice", "alice-2")
+        self.assertEqual(mcp_bridge._last_read_channel["alice-2"], "bugfixing")
+        self.assertEqual(mcp_bridge._last_read_job_id["alice-2"], 7)
+        self.assertNotIn("alice", mcp_bridge._last_read_channel)
+        self.assertNotIn("alice", mcp_bridge._last_read_job_id)
+
+    def test_purge_identity_drops_fallback_state(self):
+        mcp_bridge._last_read_channel["alice"] = "bugfixing"
+        mcp_bridge._last_read_job_id["alice"] = 7
+        mcp_bridge.purge_identity("alice")
+        self.assertNotIn("alice", mcp_bridge._last_read_channel)
+        self.assertNotIn("alice", mcp_bridge._last_read_job_id)
+
+    def test_channel_rename_rewrites_matching_fallbacks(self):
+        mcp_bridge._last_read_channel["alice"] = "bugfixing"
+        mcp_bridge._last_read_channel["bob"] = "portfolio"
+        mcp_bridge.migrate_cursors_rename("bugfixing", "hotfixes")
+        self.assertEqual(mcp_bridge._last_read_channel["alice"], "hotfixes")
+        # Other agents' fallbacks are untouched
+        self.assertEqual(mcp_bridge._last_read_channel["bob"], "portfolio")
+
+    def test_channel_delete_resets_fallbacks_to_general(self):
+        mcp_bridge._last_read_channel["alice"] = "bugfixing"
+        mcp_bridge._last_read_channel["bob"] = "portfolio"
+        mcp_bridge.migrate_cursors_delete("bugfixing")
+        self.assertEqual(mcp_bridge._last_read_channel["alice"], "general")
+        # Other agents' fallbacks are untouched
+        self.assertEqual(mcp_bridge._last_read_channel["bob"], "portfolio")
+
+
 if __name__ == "__main__":
     unittest.main()