Stage 403: PR #2852 — fix(chat): settle stream_end without done by @ai-ag2026

static/messages.js

@@ -1682,6 +1682,7 @@ function attachLiveStream(activeSid, streamId, uploaded=[], options={}){
     });
 
     source.addEventListener('done',e=>{
+      if(_streamFinalized) return;
       _terminalStateReached=true;
       if(_persistTimer){clearTimeout(_persistTimer);_persistTimer=null;}
       const _doneData=JSON.parse(e.data);
@@ -1859,12 +1860,31 @@ function attachLiveStream(activeSid, streamId, uploaded=[], options={}){
       _finishDone();
     });
 
-    source.addEventListener('stream_end',e=>{
+    source.addEventListener('stream_end',async e=>{
+      if(_streamFinalized){
+        source.close();
+        return;
+      }
       _terminalStateReached=true;
       try{
         const d=JSON.parse(e.data||'{}');
         if((d.session_id||activeSid)!==activeSid) return;
       }catch(_){}
+      // Some replay/journal paths can deliver stream_end without a preceding
+      // done event. In that case closing the EventSource is not enough: the
+      // live DOM/inflight state remains projected and can duplicate Thinking or
+      // assistant content until a later session switch. Settle from the persisted
+      // session before closing so the pane converges on canonical state.
+      if(await _restoreSettledSession()){
+        source.close();
+        return;
+      }
+      if(_persistTimer){clearTimeout(_persistTimer);_persistTimer=null;}
+      _streamFinalized=true;
+      _cancelAnimationFramePendingStreamRender();
+      _streamFadeCleanupReduceMotionListener();
+      _smdEndParser();
+      if(typeof finalizeThinkingCard==='function') finalizeThinkingCard();
       source.close();
     });
 
@@ -2135,6 +2155,12 @@ function attachLiveStream(activeSid, streamId, uploaded=[], options={}){
       const session=data&&data.session;
       if(!session) return false;
       if(session.active_stream_id||session.pending_user_message) return false;
+      if(_persistTimer){clearTimeout(_persistTimer);_persistTimer=null;}
+      _streamFinalized=true;
+      _cancelAnimationFramePendingStreamRender();
+      _streamFadeCleanupReduceMotionListener();
+      _smdEndParser();
+      if(typeof finalizeThinkingCard==='function') finalizeThinkingCard();
       _clearOwnerInflightState();
       _closeSource();
       _clearApprovalForOwner();

tests/test_1694_terminal_cleanup_ownership.py

@@ -91,3 +91,33 @@ def test_reconnect_settled_and_error_paths_keep_cleanup_session_scoped():
     assert "stopApprovalPolling();stopClarifyPolling();" not in combined
     assert "renderSessionList();setBusy(false)" not in combined
     assert "_setActivePaneIdleIfOwner" in combined
+
+def test_stream_end_without_done_restores_settled_session_before_closing():
+    """If a journal/replay emits stream_end without done, the UI must settle from /api/session.
+
+    A close-only stream_end handler leaves live Thinking/inflight DOM around and
+    never replaces the pane with the persisted transcript when done is missing.
+    """
+    body = _event_body("stream_end")
+    restore_idx = body.find("_restoreSettledSession()")
+    close_idx = body.rfind("source.close()")
+    finalized_idx = body.find("_streamFinalized=true")
+    assert restore_idx != -1, "stream_end handler must restore settled session when done is absent"
+    assert close_idx != -1, "stream_end handler must still close the EventSource"
+    assert restore_idx < close_idx, "restore must be attempted before closing the stream"
+    assert finalized_idx != -1, "stream_end terminal path must suppress trailing rAF/render work"
+
+
+def test_done_handler_is_idempotent_for_replay_or_duplicate_done_events():
+    """Duplicate/replayed done events must not replay completion sound or duplicate render."""
+    body = _event_body("done")
+    first_stmt = body.strip().splitlines()[0].strip()
+    assert "_streamFinalized" in first_stmt and "return" in first_stmt, (
+        "done handler must return early when the stream was already finalized"
+    )
+    guard_idx = body.find("if(_streamFinalized) return;")
+    sound_idx = body.find("playNotificationSound();")
+    assert sound_idx != -1, "done handler should still play completion sound once"
+    assert guard_idx != -1 and guard_idx < sound_idx, (
+        "completion sound must be behind the duplicate-done finalization guard"
+    )