fix: harden SessionStore — per-record timestamp handling, atomic writes, robust quarantine

tests/unit/test_sessions.py

@@ -67,3 +67,59 @@ class TestSessionStore:
 
         assert default_store_path().name == "sessions.json"
         assert "wabot" in str(default_store_path())
+
+    def test_naive_created_at_is_treated_as_utc_not_crash(self, tmp_path):
+        # legacy/hand-written records may carry naive timestamps
+        import json
+
+        path = tmp_path / "sessions.json"
+        record = make_record()
+        data = {"scraper1": {**record.__dict__, "created_at": "2999-01-01T00:00:00"}}
+        path.write_text(json.dumps(data))
+        store = SessionStore(path=path)
+        assert store.get("scraper1") is not None  # fresh: kept, assumed UTC
+
+    def test_garbage_created_at_evicts_only_that_record(self, tmp_path):
+        import json
+
+        path = tmp_path / "sessions.json"
+        good, bad = make_record(name="good"), make_record(name="bad")
+        data = {
+            "good": good.__dict__,
+            "bad": {**bad.__dict__, "created_at": "not-a-date"},
+        }
+        path.write_text(json.dumps(data))
+        store = SessionStore(path=path)
+        assert store.names() == ["good"]  # no crash, bad evicted, file rewritten
+        assert "not-a-date" not in path.read_text()
+
+    def test_null_created_at_evicts_only_that_record(self, tmp_path):
+        import json
+
+        path = tmp_path / "sessions.json"
+        data = {"broken": {**make_record(name="broken").__dict__, "created_at": None}}
+        path.write_text(json.dumps(data))
+        assert SessionStore(path=path).names() == []
+
+    def test_unknown_record_fields_are_ignored_not_fatal(self, tmp_path):
+        # a newer wabot may add fields; older versions must not quarantine the store
+        import json
+
+        path = tmp_path / "sessions.json"
+        data = {"scraper1": {**make_record().__dict__, "future_field": 42}}
+        path.write_text(json.dumps(data))
+        assert SessionStore(path=path).get("scraper1") is not None
+
+    def test_repeat_corruption_with_existing_bad_file_does_not_crash(self, tmp_path):
+        path = tmp_path / "sessions.json"
+        (tmp_path / "sessions.json.bad").write_text("old corruption")
+        path.write_text("{ corrupt again")
+        store = SessionStore(path=path)
+        assert store.load() == {}
+        store.save(make_record())
+        assert store.get("scraper1") is not None
+
+    def test_write_is_atomic_no_tmp_leftover(self, tmp_path):
+        store = SessionStore(path=tmp_path / "sessions.json")
+        store.save(make_record())
+        assert not (tmp_path / "sessions.json.tmp").exists()