Fix Copilot PR #3 review: timeout race, ANSI stripping, streaming perf (#5)

- Fix timeout race in _exec_bash: check proc.poll() before setting
  timed_out flag; fall back to proc.kill() if process group kill fails
- Remove stderr_thread.join(timeout=5) — after proc.wait() the pipe
  is closed so join completes promptly without risk of truncation
- Fix CSI final byte range in stripAnsi: [A-Za-z] → [@-~] to handle
  sequences like \x1b[1~ (Home key) that end in non-letter bytes
- Use appendChild(createTextNode()) instead of textContent += for O(1)
  chunk appending in streaming output (avoids O(n²) on large output)
- Use var(--accent-dim) in stream-pulse keyframe instead of hardcoded
  rgba() so pulse color adapts to light/dark theme
- Record tool_output_chunk calls in RecordingUI for test assertions

tests/test_server_live.py

@@ -66,6 +66,7 @@ class RecordingUI:
         self.content_tokens: list[str] = []
         self.reasoning_tokens: list[str] = []
         self.tool_results: list[tuple[str, str]] = []
+        self.tool_chunks: list[tuple[str, str]] = []
         self.errors: list[str] = []
         self.infos: list[str] = []
 
@@ -91,7 +92,7 @@ class RecordingUI:
         self.tool_results.append((name, output))
 
     def on_tool_output_chunk(self, call_id, chunk):
-        pass
+        self.tool_chunks.append((call_id, chunk))
 
     def on_status(self, usage, context_window, effort):
         self.events.append(("status",))

turnstone/core/session.py

@@ -1766,9 +1766,15 @@ class ChatSession:
                 timed_out = threading.Event()
 
                 def _on_timeout() -> None:
+                    if proc.poll() is not None:
+                        return  # process already exited
                     timed_out.set()
                     with contextlib.suppress(OSError, ProcessLookupError):
-                        os.killpg(os.getpgid(proc.pid), signal.SIGKILL)
+                        try:
+                            os.killpg(os.getpgid(proc.pid), signal.SIGKILL)
+                        except OSError:
+                            with contextlib.suppress(OSError, ProcessLookupError):
+                                proc.kill()
 
                 timer = threading.Timer(self.tool_timeout, _on_timeout)
                 timer.start()
@@ -1782,7 +1788,7 @@ class ChatSession:
                     timer.cancel()
 
                 proc.wait()
-                stderr_thread.join(timeout=5)
+                stderr_thread.join()
             finally:
                 os.unlink(script_path)
 

turnstone/ui/static/app.js

@@ -1345,7 +1345,7 @@ function replayHistory(messages) {
 function stripAnsi(s) {
   // Strip CSI sequences, OSC sequences, and two-byte escapes
   return s.replace(
-    /\x1b(?:\[[0-9;?]*[A-Za-z]|\][^\x07\x1b]*(?:\x07|\x1b\\)?|[()#][A-Za-z0-9]|.)/g,
+    /\x1b(?:\[[0-9;?]*[@-~]|\][^\x07\x1b]*(?:\x07|\x1b\\)?|[()#][A-Za-z0-9]|.)/g,
     "",
   );
 }
@@ -1529,7 +1529,7 @@ function appendToolOutputChunk(callId, chunk) {
     target.after(el);
   }
 
-  el.textContent += stripped;
+  el.appendChild(document.createTextNode(stripped));
   el.scrollTop = el.scrollHeight;
   scrollToBottom();
 }

turnstone/ui/static/style.css

@@ -517,7 +517,7 @@ body {
 }
 @keyframes stream-pulse {
   0%, 100% { border-left-color: var(--accent); }
-  50% { border-left-color: rgba(229, 160, 66, 0.15); }
+  50% { border-left-color: var(--accent-dim); }
 }
 .tool-output.collapsed { max-height: 150px; position: relative; }
 .tool-output.collapsed::after {