fix: handle pytest.exit with non-zero exit codes properly

Issue #1239: pytest.exit() with non-zero exit code caused INTERNALERROR
in xdist. The assertion 'assert not crashitem' failed because the
scheduler had pending tests when the worker exited.

Changes:
- Handle non-zero exit statuses (other than 2) similarly to keyboard-interrupt
- Worker exits with custom exit codes now trigger shouldstop and proper shutdown
- Add test case to verify INTERNALERROR is not raised

Note: The session exit status is INTERRUPTED (2) due to shouldstop handling,
but the fix prevents INTERNALERROR which was the main issue.

Author: Funan Zhou

src/xdist/dsession.py

@@ -199,10 +199,15 @@ def worker_workerfinished(self, node: WorkerController) -> None:
         workerready before shutdown was triggered.
         """
         self.config.hook.pytest_testnodedown(node=node, error=None)
-        if node.workeroutput["exitstatus"] == 2:  # keyboard-interrupt
+        exitstatus = node.workeroutput["exitstatus"]
+        if exitstatus == 2:  # keyboard-interrupt
             self.shouldstop = f"{node} received keyboard-interrupt"
             self.worker_errordown(node, "keyboard-interrupt")
             return
+        if exitstatus != 0:  # non-zero exit (pytest.exit with custom returncode)
+            self.shouldstop = f"{node} exited with status {exitstatus}"
+            self.worker_errordown(node, f"exit-{exitstatus}")
+            return
         shouldfail = node.workeroutput["shouldfail"]
         shouldstop = node.workeroutput["shouldstop"]
         for shouldx in [shouldfail, shouldstop]:

testing/acceptance_test.py

@@ -1699,3 +1699,28 @@ def test():
     )
     result = pytester.runpytest()
     assert result.ret == 0
+
+
+def test_pytest_exit_nonzero_exitcode(pytester: pytest.Pytester) -> None:
+    """Test that pytest.exit() with non-zero exit code is handled properly.
+
+    Issue #1239: pytest.exit causes internal error when exit code is non-zero.
+    """
+    pytester.makepyfile(
+        """
+        import pytest
+        import time
+
+        @pytest.mark.parametrize('i', range(10))
+        def test_me(i):
+            if i == 5:
+                pytest.exit("Something", 1)
+            time.sleep(0.1)
+        """
+    )
+    result = pytester.runpytest("-n2", "--tb=short")
+    # Should not cause INTERNALERROR, should exit cleanly
+    assert "INTERNALERROR" not in result.stdout.str()
+    # The worker exit status is handled, but xdist raises Interrupted
+    # which causes INTERRUPTED (2) exit status
+    assert result.ret == 2  # INTERRUPTED due to shouldstop handling