fix: odysseus-mail read crashes on an empty IMAP fetch payload (#1730)

tests/test_mail_cli_read_empty_fetch.py

@@ -0,0 +1,63 @@
+import importlib.machinery
+import importlib.util
+import sys
+from pathlib import Path
+from types import ModuleType, SimpleNamespace
+
+import pytest
+
+
+class _Conn:
+    def select(self, folder, readonly=True):
+        return "OK", [b"1"]
+
+    def fetch(self, uid, spec):
+        # IMAP can return OK with an empty payload (UID expunged mid-session).
+        return "OK", []
+
+
+class _ImapCtx:
+    def __init__(self, account):
+        pass
+
+    def __enter__(self):
+        return _Conn()
+
+    def __exit__(self, *a):
+        return False
+
+
+def _load_mail_cli(monkeypatch):
+    helpers = ModuleType("routes.email_helpers")
+    helpers._imap = _ImapCtx
+    helpers._get_email_config = lambda account=None: {}
+    helpers._decode_header = lambda value: value
+    helpers._extract_text = lambda msg: ""
+    helpers._extract_html = lambda msg: ""
+    helpers._list_attachments_from_msg = lambda msg: []
+    pollers = ModuleType("routes.email_pollers")
+    pollers._scheduled_poll_once = lambda: {}
+    pollers._run_auto_summarize_once = lambda **kwargs: ""
+    core_mod = ModuleType("core")
+    database_mod = ModuleType("core.database")
+    database_mod.SessionLocal = object
+    database_mod.EmailAccount = object
+    monkeypatch.setitem(sys.modules, "routes.email_helpers", helpers)
+    monkeypatch.setitem(sys.modules, "routes.email_pollers", pollers)
+    monkeypatch.setitem(sys.modules, "core", core_mod)
+    monkeypatch.setitem(sys.modules, "core.database", database_mod)
+    path = Path(__file__).resolve().parent.parent / "scripts" / "odysseus-mail"
+    loader = importlib.machinery.SourceFileLoader("odysseus_mail_cli_read_test", str(path))
+    spec = importlib.util.spec_from_loader(loader.name, loader)
+    module = importlib.util.module_from_spec(spec)
+    loader.exec_module(module)
+    return module
+
+
+def test_cmd_read_handles_empty_fetch_payload(monkeypatch):
+    cli = _load_mail_cli(monkeypatch)
+    args = SimpleNamespace(account="acc", folder="INBOX", uid="5", html=False)
+    # old code did raw = msg_data[0][1] on the empty list and raised IndexError;
+    # the guard turns it into a clean fail() (SystemExit).
+    with pytest.raises(SystemExit):
+        cli.cmd_read(args)