tests: error on ResourceWarning (#9123)

* tests: error on ResourceWarning

* run-cache: avoid leaking temp files on Windows

* set returncode to popen to avoid ResourceWarning on gc.collect()

dvc/daemon.py

@@ -14,7 +14,14 @@ from dvc.utils import fix_env, is_binary
 logger = logging.getLogger(__name__)
 
 
-def _popen(cmd, **kwargs):
+def _suppress_resource_warning(popen: Popen):
+    """Sets the returncode to avoid ResourceWarning when popen is garbage collected."""
+    # only use for daemon processes.
+    # See https://bugs.python.org/issue38890.
+    popen.returncode = 0
+
+
+def _popen(cmd, **kwargs) -> Popen:
     prefix = [sys.executable]
     if not is_binary():
         main_entrypoint = os.path.join(
@@ -40,7 +47,10 @@ def _spawn_windows(cmd, env):
         startupinfo = STARTUPINFO()
         startupinfo.dwFlags |= STARTF_USESHOWWINDOW
 
-        _popen(cmd, env=env, creationflags=creationflags, startupinfo=startupinfo)
+        popen = _popen(
+            cmd, env=env, creationflags=creationflags, startupinfo=startupinfo
+        )
+        _suppress_resource_warning(popen)
 
 
 def _spawn_posix(cmd, env):

dvc/stage/cache.py

@@ -1,6 +1,5 @@
 import logging
 import os
-import tempfile
 from contextlib import contextmanager
 from typing import TYPE_CHECKING, List, Optional, Tuple
 
@@ -167,9 +166,10 @@ class StageCache:
         COMPILED_LOCK_FILE_STAGE_SCHEMA(cache)
 
         path = self._get_cache_path(cache_key, cache_value)
-        parent = self.repo.cache.local.fs.path.parent(path)
+        local_fs = self.repo.cache.local.fs
+        parent = local_fs.path.parent(path)
         self.repo.cache.local.makedirs(parent)
-        tmp = tempfile.NamedTemporaryFile(delete=False, dir=parent).name
+        tmp = local_fs.path.join(parent, fs.utils.tmp_fname())
         assert os.path.exists(parent)
         assert os.path.isdir(parent)
         dump_yaml(tmp, cache)

pyproject.toml

@@ -132,6 +132,8 @@ profile = "black"
 [tool.pytest.ini_options]
 addopts = "-ra --cov-config pyproject.toml --dist worksteal"
 filterwarnings = [
+    "error::ResourceWarning",
+    "error::pytest.PytestUnraisableExceptionWarning",
     "error::pytest_mock.PytestMockWarning",
     # remove when aiobotocore supports botocore>=1.29.13
     "ignore:'cgi' is deprecated and slated for removal in Python 3.13:DeprecationWarning",