Display exception name when subprocesses raise them (#3450)

Author: ssbarnea

docs/changelog/3450.bugfix.rst

@@ -0,0 +1,3 @@
+Log exception name when subprocess execution produces one.
+
+- by :user:`ssbarnea`

src/tox/execute/local_sub_process/__init__.py

@@ -214,6 +214,9 @@ def __enter__(self) -> ExecuteStatus:
                 env=self.request.env,
             )
         except OSError as exception:
+            # We log a nice error message to avout returning opaque error codes,
+            # like exit code 2 (filenotfound).
+            logging.error("Exception running subprocess %s", str(exception))  # noqa: TRY400
             return LocalSubprocessExecuteFailedStatus(self.options, self._out, self._err, exception.errno)
 
         status = LocalSubprocessExecuteStatus(self.options, self._out, self._err, process)

tests/execute/local_subprocess/test_local_subprocess.py

@@ -4,6 +4,7 @@
 import locale
 import logging
 import os
+import re
 import shutil
 import stat
 import subprocess
@@ -264,7 +265,11 @@ def test_command_does_not_exist(caplog: LogCaptureFixture, os_env: dict[str, str
     assert outcome.exit_code != Outcome.OK
     assert not outcome.out
     assert not outcome.err
-    assert not caplog.records
+    assert len(caplog.records) == 1
+    assert caplog.records[0].levelname == "ERROR"
+    assert re.match(
+        r".*(No such file or directory|The system cannot find the file specified).*", caplog.records[0].message
+    )
 
 
 @pytest.mark.skipif(sys.platform == "win32", reason="You need a conhost shell for keyboard interrupt")