fix: clear runtime fields on loaded compression snapshots

CHANGELOG.md

@@ -8,6 +8,8 @@
 
 ### Fixed
 
+- **PR #2337** by @Michaelyklam (closes #2336) — Pre-compression snapshot preservation now also clears stale runtime stream fields when the existing on-disk snapshot is already as complete as the in-memory session. This keeps the load-and-mark branch aligned with the full-save branch and adds regression coverage so archived parent snapshots cannot retain stale `active_stream_id` / `pending_*` state.
+
 - **PR #2322** by @Michaelyklam (refs #2271) — LAN Ollama models selected from endpoint-discovered `custom:<host>-<port>` / `custom:<host>:<port>` picker entries now route through the configured `ollama` provider and base URL instead of surfacing a missing `CUSTOM_*_API_KEY` error. The picker still surfaces endpoint-discovered entries; the fix is to recognize them as UI routing hints matching the configured local-server base URL and resolve them via the actual `ollama` provider.
 
 

api/streaming.py

@@ -1738,8 +1738,6 @@ def _preserve_pre_compression_snapshot(s, old_sid: str) -> None:
             # than leaving an unreadable recovery snapshot behind.
             existing_msgs = -1
             existing_snapshot = False
-        if len(s.messages) <= existing_msgs and existing_snapshot:
-            return
         if len(s.messages) > existing_msgs:
             # In-memory messages are newer than the file; save the full old
             # snapshot from the current session object while preserving its

tests/test_compression_snapshot_runtime_clear.py

@@ -1,5 +1,6 @@
 import json
 
+from api import models
 from api import streaming
 
 
@@ -62,3 +63,35 @@ def test_preserve_pre_compression_snapshot_clears_runtime_fields_while_restoring
     assert saved["pending_user_message"] is None
     assert saved["pending_attachments"] == []
     assert saved["pending_started_at"] is None
+
+
+def test_preserve_pre_compression_snapshot_load_and_mark_branch_clears_runtime_fields(tmp_path, monkeypatch):
+    monkeypatch.setattr(streaming, "SESSION_DIR", tmp_path)
+    monkeypatch.setattr(models, "SESSION_DIR", tmp_path)
+    old_payload = {
+        "session_id": "old_session",
+        "title": "Archived parent",
+        "messages": [
+            {"role": "user", "content": "older prompt"},
+            {"role": "assistant", "content": "older answer"},
+            {"role": "user", "content": "newer prompt already on disk"},
+        ],
+        "pre_compression_snapshot": True,
+        "active_stream_id": "stale-stream",
+        "pending_user_message": "stale prompt",
+        "pending_attachments": [{"name": "stale.txt"}],
+        "pending_started_at": 12345,
+    }
+    (tmp_path / "old_session.json").write_text(json.dumps(old_payload), encoding="utf-8")
+    session = FakeSession()
+    session.messages = [{"role": "user", "content": "current prompt"}]
+
+    streaming._preserve_pre_compression_snapshot(session, "old_session")
+
+    saved = json.loads((tmp_path / "old_session.json").read_text(encoding="utf-8"))
+    assert saved["messages"] == old_payload["messages"]
+    assert saved["pre_compression_snapshot"] is True
+    assert saved["active_stream_id"] is None
+    assert saved["pending_user_message"] is None
+    assert saved["pending_attachments"] == []
+    assert saved["pending_started_at"] is None