fix(email): use UID commands instead of sequence numbers in IMAP fetches (#5149)

conn.search() / conn.fetch() operate on volatile positional sequence
numbers that shift whenever messages are deleted or expunged. Three call
sites in the sig-learner (_pull_headers, _fetch_bodies) and morning-brief
email section were storing these as "uid" and reusing them in subsequent
fetches — causing wrong-message returns or NO responses if another client
modified the mailbox concurrently.

Replaced with conn.uid("SEARCH", ...) / conn.uid("FETCH", ...), which use
persistent RFC 3501 UIDs. _scan_one (urgency action) already did this
correctly; these were the remaining callers.

The reproduction window is narrow (requires concurrent deletion between
search and fetch), so the fix is verified by regression tests rather than
manual end-to-end: _SpyImap raises AssertionError if conn.search() or
conn.fetch() are called instead of conn.uid().

src/builtin_actions.py

@@ -1125,14 +1125,14 @@ async def action_learn_sender_signatures(owner: str, **kwargs) -> Tuple[str, boo
             conn = _imap_connect(None, owner=owner)
             try:
                 conn.select("INBOX", readonly=True)
-                status, data = conn.search(None, "ALL")
+                status, data = conn.uid("SEARCH", None, "ALL")
                 if status != "OK" or not data or not data[0]:
                     return results
                 uids = data[0].split()[-300:][::-1]  # newest 300
                 for uid in uids:
                     try:
-                        st, msg_data = conn.fetch(
-                            uid, "(BODY.PEEK[HEADER.FIELDS (FROM)])"
+                        st, msg_data = conn.uid(
+                            "FETCH", uid, "(BODY.PEEK[HEADER.FIELDS (FROM)])"
                         )
                         if st != "OK" or not msg_data or not msg_data[0]:
                             continue
@@ -1214,7 +1214,7 @@ async def action_learn_sender_signatures(owner: str, **kwargs) -> Tuple[str, boo
                     conn2.select("INBOX", readonly=True)
                     for mm in _msgs:
                         try:
-                            st, data = conn2.fetch(mm["uid"], "(BODY.PEEK[TEXT])")
+                            st, data = conn2.uid("FETCH", mm["uid"], "(BODY.PEEK[TEXT])")
                             if st != "OK" or not data or not data[0]:
                                 continue
                             raw = data[0][1] if isinstance(data[0], tuple) else None
@@ -1356,13 +1356,13 @@ async def action_daily_brief(owner: str, **kwargs) -> Tuple[str, bool]:
             conn = _imap_connect(None)
             try:
                 conn.select("INBOX", readonly=True)
-                status, data = conn.search(None, "UNSEEN")
+                status, data = conn.uid("SEARCH", None, "UNSEEN")
                 uids = (data[0].split() if status == "OK" and data and data[0] else [])
                 unread_count = len(uids)
                 # Grab headers for the most recent 5 unread (UIDs increase with arrival)
                 for uid in uids[-5:][::-1]:
                     try:
-                        _, msg_data = conn.fetch(uid, "(BODY.PEEK[HEADER.FIELDS (FROM SUBJECT)])")
+                        _, msg_data = conn.uid("FETCH", uid, "(BODY.PEEK[HEADER.FIELDS (FROM SUBJECT)])")
                         if not msg_data or not msg_data[0]:
                             continue
                         hdr = msg_data[0][1] if isinstance(msg_data[0], tuple) else msg_data[0]

tests/test_builtin_actions_owner_scope.py

@@ -109,10 +109,9 @@ async def test_learn_sender_signatures_resolves_llm_for_task_owner(monkeypatch):
         def select(self, *_args, **_kwargs):
             return "OK", []
 
-        def search(self, *_args, **_kwargs):
-            return "OK", [b"1 2 3"]
-
-        def fetch(self, _uid, _query):
+        def uid(self, command, *_args):
+            if command == "SEARCH":
+                return "OK", [b"1 2 3"]
             return "OK", [(None, b"From: Writer <writer@example.com>\r\n\r\n")]
 
         def logout(self):
@@ -171,11 +170,10 @@ async def test_learn_sender_signatures_writes_owner_scoped_cache(monkeypatch, tm
         def select(self, *_args, **_kwargs):
             return "OK", []
 
-        def search(self, *_args, **_kwargs):
-            return "OK", [b"1 2 3"]
-
-        def fetch(self, uid, query):
-            if "HEADER.FIELDS" in query:
+        def uid(self, command, uid=None, query=None):
+            if command == "SEARCH":
+                return "OK", [b"1 2 3"]
+            if query and "HEADER.FIELDS" in query:
                 return "OK", [(None, b"From: Writer <writer@example.com>\r\n\r\n")]
             return "OK", [
                 (

tests/test_imap_uid_commands.py

@@ -0,0 +1,108 @@
+"""Regression: IMAP calls must use uid() not search()/fetch().
+
+conn.search() / conn.fetch() operate on volatile positional sequence
+numbers that shift whenever messages are deleted or expunged. The
+sig-learner and daily-brief actions must use conn.uid("SEARCH", ...)
+and conn.uid("FETCH", ...) which address messages by their persistent
+RFC 3501 UID (§2.3.1.1, §6.4.8).
+"""
+import pytest
+
+
+class _SpyImap:
+    """IMAP stub that records uid() calls and raises on search()/fetch()."""
+
+    def __init__(self, uid_list=b"1 2 3"):
+        self._uid_list = uid_list
+        self.uid_calls: list[tuple] = []
+
+    def select(self, *args, **kwargs):
+        return "OK", []
+
+    def uid(self, command, *args):
+        self.uid_calls.append((command,) + args)
+        if command == "SEARCH":
+            return "OK", [self._uid_list]
+        if command == "FETCH":
+            query = args[1] if len(args) > 1 else ""
+            if "HEADER.FIELDS" in query:
+                return "OK", [(None, b"From: Writer <writer@example.com>\r\n"
+                                     b"Subject: Hello\r\n\r\n")]
+            return "OK", [(None, b"Body text\r\n\r\nRegards,\r\nThe Writer\r\n")]
+        return "OK", []
+
+    def search(self, *args):
+        raise AssertionError("conn.search() called — must use conn.uid('SEARCH', ...) instead")
+
+    def fetch(self, *args):
+        raise AssertionError("conn.fetch() called — must use conn.uid('FETCH', ...) instead")
+
+    def logout(self):
+        pass
+
+
+@pytest.mark.asyncio
+async def test_sig_learner_uses_uid_search(monkeypatch):
+    """_pull_headers must call conn.uid('SEARCH', ...) not conn.search()."""
+    from routes import email_helpers
+    from src import task_endpoint
+    from src.builtin_actions import action_learn_sender_signatures
+
+    spy = _SpyImap()
+    monkeypatch.setattr(email_helpers, "_imap_connect", lambda *a, **kw: spy)
+    monkeypatch.setattr(task_endpoint, "resolve_task_candidates", lambda *a, **kw: [])
+
+    message, ok = await action_learn_sender_signatures("alice")
+
+    assert ok is False  # no LLM candidates — stops before LLM, after IMAP
+    assert any(c[0] == "SEARCH" for c in spy.uid_calls), "uid('SEARCH', ...) was not called"
+
+
+@pytest.mark.asyncio
+async def test_sig_learner_uses_uid_fetch(monkeypatch):
+    """_pull_headers must call conn.uid('FETCH', ...) not conn.fetch()."""
+    from routes import email_helpers
+    from src import task_endpoint
+    from src.builtin_actions import action_learn_sender_signatures
+
+    spy = _SpyImap()
+    monkeypatch.setattr(email_helpers, "_imap_connect", lambda *a, **kw: spy)
+    monkeypatch.setattr(task_endpoint, "resolve_task_candidates", lambda *a, **kw: [])
+
+    await action_learn_sender_signatures("alice")
+
+    assert any(c[0] == "FETCH" for c in spy.uid_calls), "uid('FETCH', ...) was not called"
+
+
+@pytest.mark.asyncio
+async def test_daily_brief_uses_uid_commands(monkeypatch):
+    """action_daily_brief email section must use uid() not search()/fetch()."""
+    from core import database
+    from core import auth as _auth_mod
+    from routes import email_helpers
+    from src.builtin_actions import action_daily_brief
+
+    class _Q:
+        def filter(self, *a, **kw): return self
+        def join(self, *a, **kw): return self
+        def order_by(self, *a): return self
+        def all(self): return []
+
+    class _Db:
+        def query(self, *a): return _Q()
+        def close(self): pass
+
+    class _FakeAuth:
+        is_configured = False
+
+    monkeypatch.setattr(database, "SessionLocal", _Db)
+    monkeypatch.setattr(_auth_mod, "AuthManager", lambda: _FakeAuth())
+
+    spy = _SpyImap(uid_list=b"10 20 30")
+    monkeypatch.setattr(email_helpers, "_imap_connect", lambda *a, **kw: spy)
+
+    message, ok = await action_daily_brief("")
+
+    assert ok is True
+    assert any(c[0] == "SEARCH" for c in spy.uid_calls), "uid('SEARCH', ...) was not called"
+    assert any(c[0] == "FETCH" for c in spy.uid_calls), "uid('FETCH', ...) was not called"