Fix: Report worker process exit codes in error messages

changelog/1278.bugfix.rst

@@ -0,0 +1 @@
+Worker process exit codes are now reported when the process terminates abnormally (e.g., via native code calling ``exit()`` directly). The exit code is included in the error message, helping diagnose crashes that bypass Python's exception handling.

src/xdist/workermanage.py

@@ -389,6 +389,25 @@ def notify_inproc(self, eventname: str, **kwargs: object) -> None:
         self.log(f"queuing {eventname}(**{kwargs})")
         self.putevent((eventname, kwargs))
 
+    def _get_worker_exit_code(self) -> int | None:
+        """Get the exit code of the worker process, if available.
+
+        Returns the exit code if the worker process has terminated,
+        or None if the exit code cannot be determined (e.g., for
+        non-popen gateways or if the process hasn't terminated yet).
+        """
+        try:
+            io = getattr(self.gateway, "_io", None)
+            if io is None:
+                return None
+            popen = getattr(io, "popen", None)
+            if popen is None:
+                return None
+            # Poll to check if process has terminated and get return code
+            return popen.poll()
+        except Exception:
+            return None
+
     def process_from_remote(
         self, eventcall: tuple[str, dict[str, Any]] | Literal[Marker.END]
     ) -> None:
@@ -404,7 +423,14 @@ def process_from_remote(
                 err: object | None = self.channel._getremoteerror()  # type: ignore[no-untyped-call]
                 if not self._down:
                     if not err or isinstance(err, EOFError):
-                        err = "Not properly terminated"  # lost connection?
+                        # Check if the worker process exited with non-zero status
+                        # This handles cases like direct exit(1) calls from native code
+                        # where Python exception handling is bypassed (#1278)
+                        exit_code = self._get_worker_exit_code()
+                        if exit_code is not None and exit_code != 0:
+                            err = f"Worker exited with non-zero exit code: {exit_code}"
+                        else:
+                            err = "Not properly terminated"  # lost connection?
                     self.notify_inproc("errordown", node=self, error=err)
                     self._down = True
                 return

testing/acceptance_test.py

@@ -666,6 +666,24 @@ def test_ok():
     )
 
 
+def test_exit_code_reported_in_error(pytester: pytest.Pytester) -> None:
+    """Ensure worker exit code is reported when process terminates (#1278).
+
+    This specifically tests for cases where native code terminates the process
+    directly (e.g., via C's exit() function), bypassing Python exception handling.
+    """
+    pytester.makepyfile(
+        """
+        import os
+        def test_exit_nonzero():
+            os._exit(42)
+    """
+    )
+    result = pytester.runpytest("-n1", "-v")
+    # The error message should include the exit code
+    result.stdout.fnmatch_lines(["*exit code*42*"])
+
+
 def test_multiple_log_reports(pytester: pytest.Pytester) -> None:
     """
     Ensure that pytest-xdist supports plugins that emit multiple logreports