Fix tox is not exiting because package env thread holding it up

Signed-off-by: Bernát Gábor <bgabor8@bloomberg.net>

10 files changed, 63 insertions, 25 deletions

diff --git a/docs/changelog/1915.bugfix.rst b/docs/changelog/1915.bugfix.rst
new file mode 100644
index 00000000..d3e137a9
--- /dev/null
+++ b/docs/changelog/1915.bugfix.rst
@@ -0,0 +1,2 @@
+Fix a bug that caused tox to never finish when pulling configuration from a tox run environment that was never executed
+- by :user:`gaborbernat`.
diff --git a/docs/changelog/1915.feature.rst b/docs/changelog/1915.feature.rst
new file mode 100644
index 00000000..562c9dfe
--- /dev/null
+++ b/docs/changelog/1915.feature.rst
@@ -0,0 +1,3 @@
+The ``_TOX_SHOW_THREAD`` environment variable can be used to print alive threads when tox exists (useful to debug
+when tox hangs because of some non-finished thread) and also now prints the pid of the local subprocess when reporting
+the outcome of a execution - by :user:`gaborbernat`.
diff --git a/src/tox/execute/api.py b/src/tox/execute/api.py
index 338494e9..aa996ef2 100644
--- a/src/tox/execute/api.py
+++ b/src/tox/execute/api.py
@@ -7,7 +7,7 @@ import time
 from abc import ABC, abstractmethod
 from contextlib import contextmanager
 from types import TracebackType
-from typing import Callable, Iterator, NoReturn, Optional, Sequence, Tuple, Type
+from typing import Any, Callable, Dict, Iterator, NoReturn, Optional, Sequence, Tuple, Type
 
 from colorama import Fore
 
@@ -57,6 +57,10 @@ class ExecuteStatus(ABC):
     def err(self) -> bytearray:
         return self._err.content
 
+    @property
+    def metadata(self) -> Dict[str, Any]:
+        return {}
+
 
 class Execute(ABC):
     """Abstract API for execution of a tox environment"""
@@ -79,7 +83,9 @@ class Execute(ABC):
                 exit_code = status.exit_code
         finally:
             end = time.monotonic()
-        status.outcome = Outcome(request, show, exit_code, out_sync.text, err_sync.text, start, end, instance.cmd)
+        status.outcome = Outcome(
+            request, show, exit_code, out_sync.text, err_sync.text, start, end, instance.cmd, status.metadata
+        )
 
     @abstractmethod
     def build_instance(
@@ -138,6 +144,7 @@ class Outcome:
         start: float,
         end: float,
         cmd: Sequence[str],
+        metadata: Dict[str, Any],
     ):
         self.request = request
         self.show_on_standard = show_on_standard
@@ -147,6 +154,7 @@ class Outcome:
         self.start = start
         self.end = end
         self.cmd = cmd
+        self.metadata = metadata
 
     def __bool__(self) -> bool:
         return self.exit_code == self.OK
@@ -179,7 +187,18 @@ class Outcome:
 
     def log_run_done(self, lvl: int) -> None:
         req = self.request
-        LOGGER.log(lvl, "exit %s (%.2f seconds) %s> %s", self.exit_code, self.elapsed, req.cwd, req.shell_cmd)
+        metadata = ""
+        if self.metadata:
+            metadata = f" {', '.join(f'{k}={v}' for k, v in self.metadata.items())}"
+        LOGGER.log(
+            lvl,
+            "exit %s (%.2f seconds) %s> %s%s",
+            self.exit_code,
+            self.elapsed,
+            req.cwd,
+            req.shell_cmd,
+            metadata,
+        )
 
     @property
     def elapsed(self) -> float:
diff --git a/src/tox/execute/local_sub_process/__init__.py b/src/tox/execute/local_sub_process/__init__.py
index ebb5b495..ed4f6690 100644
--- a/src/tox/execute/local_sub_process/__init__.py
+++ b/src/tox/execute/local_sub_process/__init__.py
@@ -6,7 +6,7 @@ import sys
 import time
 from subprocess import DEVNULL, PIPE, TimeoutExpired
 from types import TracebackType
-from typing import TYPE_CHECKING, Generator, List, Optional, Sequence, Tuple, Type
+from typing import TYPE_CHECKING, Any, Dict, Generator, List, Optional, Sequence, Tuple, Type
 
 from ..api import Execute, ExecuteInstance, ExecuteStatus
 from ..request import ExecuteRequest, StdinSource
@@ -134,6 +134,10 @@ class LocalSubprocessExecuteStatus(ExecuteStatus):
     def __repr__(self) -> str:
         return f"{self.__class__.__name__}(pid={self._process.pid}, returncode={self._process.returncode!r})"
 
+    @property
+    def metadata(self) -> Dict[str, Any]:
+        return {"pid": self._process.pid} if self._process.pid else {}
+
 
 class LocalSubprocessExecuteFailedStatus(ExecuteStatus):
     def __init__(self, out: SyncWrite, err: SyncWrite, exit_code: Optional[int]) -> None:
diff --git a/src/tox/run.py b/src/tox/run.py
index aaeeb427..eb2222ee 100644
--- a/src/tox/run.py
+++ b/src/tox/run.py
@@ -1,5 +1,6 @@
 """Main entry point for tox."""
 import logging
+import os
 import sys
 import time
 from itertools import chain
@@ -27,6 +28,12 @@ def run(args: Optional[Sequence[str]] = None) -> None:
             raise
     except KeyboardInterrupt:
         result = -2
+    finally:
+        if "_TOX_SHOW_THREAD" in os.environ:  # pragma: no cover
+            import threading  # pragma: no cover
+
+            for thread in threading.enumerate():  # pragma: no cover
+                print(thread)  # pragma: no cover
     raise SystemExit(result)
 
 
diff --git a/src/tox/session/cmd/run/common.py b/src/tox/session/cmd/run/common.py
index d39b0279..9869cbcb 100644
--- a/src/tox/session/cmd/run/common.py
+++ b/src/tox/session/cmd/run/common.py
@@ -202,11 +202,6 @@ def execute(state: State, max_workers: Optional[int], has_spinner: bool, live: b
         exit_code = report(state.options.start, ordered_results, state.options.is_colored)
         if has_previous:
             signal(SIGINT, previous)
-        if "_TOX_SHOW_THREAD" in os.environ:  # pragma: no cover
-            import threading  # pragma: no cover
-
-            for thread in threading.enumerate():  # pragma: no cover
-                print(thread)  # pragma: no cover
     return exit_code
 
 
@@ -299,7 +294,12 @@ def _queue_and_wait(
             finally:
                 executor.shutdown(wait=True)
     finally:
-        done.set()
+        try:
+            # call teardown - configuration only environments for example could not be finished
+            for _, tox_env in state.run_envs():
+                tox_env.teardown()
+        finally:
+            done.set()
 
 
 def _handle_one_run_done(result: ToxEnvRunResult, spinner: ToxSpinner, state: State, live: bool) -> None:
diff --git a/src/tox/session/state.py b/src/tox/session/state.py
index 6ca22e65..d43813c8 100644
--- a/src/tox/session/state.py
+++ b/src/tox/session/state.py
@@ -126,6 +126,9 @@ class State:
             self._pkg_env[name] = packager, pkg_tox_env
         return pkg_tox_env
 
+    def run_envs(self) -> Iterator[Tuple[str, RunToxEnv]]:
+        yield from self._run_env.items()
+
 
 @impl
 def tox_add_option(parser: "ToxParser") -> None:
diff --git a/src/tox/tox_env/python/virtual_env/package/api.py b/src/tox/tox_env/python/virtual_env/package/api.py
index e8c2e22f..60359df9 100644
--- a/src/tox/tox_env/python/virtual_env/package/api.py
+++ b/src/tox/tox_env/python/virtual_env/package/api.py
@@ -279,16 +279,17 @@ class Pep517VirtualEnvPackage(VirtualEnv, PythonPackage, Frontend):
         return env
 
     def teardown(self) -> None:
-        self.ref_count.decrement()
-        if self.ref_count.value == 0 and self._backend_executor is not None and self._teardown_done is False:
-            self._teardown_done = True
-            try:
-                if self.backend_executor.is_alive:
-                    self._send("_exit")  # try first on amicable shutdown
-            except SystemExit:  # if already has been interrupted ignore
-                pass
-            finally:
-                self._backend_executor.close()
+        if not self._teardown_done:
+            self.ref_count.decrement()
+            if self.ref_count.value == 0 and self._backend_executor is not None and self._teardown_done is False:
+                self._teardown_done = True
+                try:
+                    if self.backend_executor.is_alive:
+                        self._send("_exit")  # try first on amicable shutdown
+                except SystemExit:  # if already has been interrupted ignore
+                    pass
+                finally:
+                    self._backend_executor.close()
 
     @contextmanager
     def _send_msg(
diff --git a/tests/execute/local_subprocess/test_local_subprocess.py b/tests/execute/local_subprocess/test_local_subprocess.py
index cb9e69f8..0f58ee1b 100644
--- a/tests/execute/local_subprocess/test_local_subprocess.py
+++ b/tests/execute/local_subprocess/test_local_subprocess.py
@@ -181,13 +181,14 @@ def test_local_execute_basic_fail(capsys: CaptureFixture, caplog: LogCaptureFixt
     assert len(caplog.records) == 1
     record = caplog.records[0]
     assert record.levelno == logging.CRITICAL
-    assert record.msg == "exit %s (%.2f seconds) %s> %s"
-    _code, _duration, _cwd, _cmd = record.args
+    assert record.msg == "exit %s (%.2f seconds) %s> %s%s"
+    _code, _duration, _cwd, _cmd, _metadata = record.args
     assert _code == 3
     assert _cwd == cwd
     assert _cmd == request.shell_cmd
     assert isinstance(_duration, float)
     assert _duration > 0
+    assert _metadata.startswith(" pid=")
 
 
 def test_command_does_not_exist(caplog: LogCaptureFixture, os_env: Dict[str, str]) -> None:
diff --git a/tox.ini b/tox.ini
index 4974ece6..a02b751f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -118,9 +118,8 @@ commands =
 
 [testenv:release]
 description = do a release, required posarg of the version number
-passenv =
-    *
 basepython = python3.8
+skip_install = true
 deps =
     gitpython>=3.1
     packaging>=20.9
@@ -133,7 +132,6 @@ description = dev environment with all deps at {envdir}
 usedevelop = true
 deps =
     {[testenv:release]deps}
-    setuptools_scm>=3
 extras =
     docs
     testing