PR feedback

Author: jberg5

Lib/concurrent/futures/process.py

@@ -474,18 +474,20 @@ def _terminate_broken(self, cause):
         bpe = BrokenProcessPool("A process in the process pool was "
                                 "terminated abruptly while the future was "
                                 "running or pending.")
+        cause_str = None
         if cause is not None:
-            bpe.__cause__ = _RemoteTraceback(
-                f"\n'''\n{''.join(cause)}'''")
+            cause_str = ''.join(cause)
         else:
-            # No cause known, so try to report some helpful info about
-            # which process(es) terminated and with what exit code
+            # No cause known, synthesize from child process exitcodes
             errors = []
             for p in self.processes.values():
-                if p.exitcode:  # Report any nonzero exit codes
-                    errors.append(f"Process {p.pid} terminated abruptly with exit code {p.exitcode}")
+                if p.exitcode is not None and p.exitcode != 0:
+                    errors.append(f"Process {p.pid} terminated abruptly "
+                                  f"with exit code {p.exitcode}")
             if errors:
-                bpe.__cause__ = _RemoteTraceback("\n".join(errors))
+                cause_str = "\n".join(errors)
+        if cause_str:
+            bpe.__cause__ = _RemoteTraceback(f"\n'''\n{cause_str}'''")
 
         # Mark pending tasks as failed.
         for work_id, work_item in self.pending_work_items.items():

Lib/test/test_concurrent_futures/test_process_pool.py

@@ -1,4 +1,3 @@
-import ctypes
 import os
 import queue
 import sys
@@ -108,21 +107,25 @@ def test_traceback(self):
                       f1.getvalue())
 
     @staticmethod
-    def _segfault():
-        ctypes.string_at(0)
+    def _terminate_abruptly_with_exit_code(exit_code):
+        os._exit(exit_code)
 
-    def test_traceback_when_child_process_segfaults(self):
+    def test_traceback_when_child_process_terminates_abruptly(self):
         # gh-139462 enhancement - BrokenProcessPool exceptions
         # should describe which process terminated.
-        future = self.executor.submit(self._segfault)
-        with self.assertRaises(Exception) as cm:
+        exit_code = 99
+        future = self.executor.submit(
+            self._terminate_abruptly_with_exit_code,
+            exit_code
+        )
+        with self.assertRaises(BrokenProcessPool) as bpe:
             future.result()
 
-        bpe = cm.exception
-        self.assertIs(type(bpe), BrokenProcessPool)
-        cause = bpe.__cause__
-        self.assertIs(type(cause), futures.process._RemoteTraceback)
-        self.assertIn("terminated abruptly with exit code", cause.tb)
+        cause = bpe.exception.__cause__
+        self.assertIsInstance(cause, futures.process._RemoteTraceback)
+        self.assertIn(
+            f"terminated abruptly with exit code {exit_code}", cause.tb
+        )
 
     @warnings_helper.ignore_fork_in_thread_deprecation_warnings()
     @hashlib_helper.requires_hashdigest('md5')