Add timeout and symbol length limits to demangling (#540)

Author: NicoHinderling

src/launchpad/utils/apple/cwl_demangle.py

@@ -4,6 +4,7 @@
 import shutil
 import subprocess
 import tempfile
+import time
 import uuid
 
 from dataclasses import dataclass
@@ -13,6 +14,12 @@
 
 logger = get_logger(__name__)
 
+# Default timeout for cwl-demangle subprocess (in seconds)
+DEFAULT_DEMANGLE_TIMEOUT = int(os.environ.get("LAUNCHPAD_DEMANGLE_TIMEOUT", "10"))
+
+# Default chunk size for batching symbols
+DEFAULT_CHUNK_SIZE = int(os.environ.get("LAUNCHPAD_DEMANGLE_CHUNK_SIZE", "500"))
+
 
 @dataclass
 class CwlDemangleResult:
@@ -75,7 +82,7 @@ def demangle_all(self) -> Dict[str, CwlDemangleResult]:
         self.queue.clear()
 
         # Process in chunks to avoid potential issues with large inputs
-        chunk_size = 5000
+        chunk_size = DEFAULT_CHUNK_SIZE
         total_chunks = (len(names) + chunk_size - 1) // chunk_size
 
         chunks: List[Tuple[List[str], int]] = []
@@ -84,7 +91,7 @@ def demangle_all(self) -> Dict[str, CwlDemangleResult]:
             chunk_idx = i // chunk_size
             chunks.append((chunk, chunk_idx))
 
-        # Only use parallel processing if workload justifies multiprocessing overhead (≥4 chunks = ≥20K symbols)
+        # Only use parallel processing if workload justifies multiprocessing overhead (≥4 chunks)
         do_in_parallel = self.use_parallel and total_chunks >= 4
 
         logger.debug(
@@ -149,6 +156,8 @@ def _demangle_chunk_worker(
     if not chunk:
         return {}
 
+    start_time = time.time()
+
     binary_path = shutil.which("cwl-demangle")
     if binary_path is None:
         logger.error("cwl-demangle binary not found in PATH")
@@ -178,9 +187,16 @@ def _demangle_chunk_worker(
             command_parts.append("--continue-on-error")
 
         try:
-            result = subprocess.run(command_parts, capture_output=True, text=True, check=True)
+            result = subprocess.run(
+                command_parts, capture_output=True, text=True, check=True, timeout=DEFAULT_DEMANGLE_TIMEOUT
+            )
+        except subprocess.TimeoutExpired:
+            elapsed = time.time() - start_time
+            logger.exception("cwl-demangle subprocess timed out", extra={"chunk_idx": chunk_idx, "elapsed": elapsed})
+            return {}
         except subprocess.CalledProcessError:
-            logger.exception(f"cwl-demangle failed for chunk {chunk_idx}")
+            elapsed = time.time() - start_time
+            logger.exception("cwl-demangle subprocess failed", extra={"chunk_idx": chunk_idx, "elapsed": elapsed})
             return {}
 
         batch_result = json.loads(result.stdout)

tests/integration/test_cwl_demangle.py

@@ -100,6 +100,21 @@ def test_environment_variable_disables_parallel(self):
             demangler = CwlDemangler()
             assert demangler.use_parallel is False
 
+    def test_timeout_configuration(self):
+        """Test LAUNCHPAD_DEMANGLE_TIMEOUT env var configures timeout."""
+        demangler = CwlDemangler()
+
+        # Test with custom timeout
+        with mock.patch.dict(os.environ, {"LAUNCHPAD_DEMANGLE_TIMEOUT": "10"}):
+            # Generate a few symbols to trigger sequential processing
+            symbols = self._generate_symbols(100)
+            for symbol in symbols:
+                demangler.add_name(symbol)
+
+            result = demangler.demangle_all()
+            # Should succeed with custom timeout
+            assert len(result) == 100
+
     def _generate_symbols(self, count: int) -> list[str]:
         """Generate valid Swift mangled symbols."""
         letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"