Use warnings module directly with cacheprovider (#6740)

src/_pytest/cacheprovider.py

@@ -71,10 +71,10 @@ class Cache:
         return resolve_from_str(config.getini("cache_dir"), config.rootdir)
 
     def warn(self, fmt, **args):
-        from _pytest.warnings import _issue_warning_captured
+        import warnings
         from _pytest.warning_types import PytestCacheWarning
 
-        _issue_warning_captured(
+        warnings.warn(
             PytestCacheWarning(fmt.format(**args) if args else fmt),
             self._config.hook,
             stacklevel=3,

src/_pytest/warnings.py

@@ -136,6 +136,15 @@ def pytest_terminal_summary(terminalreporter):
         yield
 
 
+@pytest.hookimpl(hookwrapper=True)
+def pytest_sessionfinish(session):
+    config = session.config
+    with catch_warnings_for_item(
+        config=config, ihook=config.hook, when="config", item=None
+    ):
+        yield
+
+
 def _issue_warning_captured(warning, hook, stacklevel):
     """
     This function should be used instead of calling ``warnings.warn`` directly when we are in the "configure" stage:

testing/test_cacheprovider.py

@@ -56,9 +56,7 @@ class TestNewAPI:
             testdir.tmpdir.ensure_dir(".pytest_cache").chmod(mode)
 
     @pytest.mark.skipif(sys.platform.startswith("win"), reason="no chmod on windows")
-    @pytest.mark.filterwarnings(
-        "ignore:could not create cache path:pytest.PytestWarning"
-    )
+    @pytest.mark.filterwarnings("default")
     def test_cache_failure_warns(self, testdir, monkeypatch):
         monkeypatch.setenv("PYTEST_DISABLE_PLUGIN_AUTOLOAD", "1")
         cache_dir = str(testdir.tmpdir.ensure_dir(".pytest_cache"))
@@ -70,7 +68,15 @@ class TestNewAPI:
             assert result.ret == 1
             # warnings from nodeids, lastfailed, and stepwise
             result.stdout.fnmatch_lines(
-                ["*could not create cache path*", "*3 warnings*"]
+                [
+                    # Validate location/stacklevel of warning from cacheprovider.
+                    "*= warnings summary =*",
+                    "*/cacheprovider.py:314",
+                    "  */cacheprovider.py:314: PytestCacheWarning: could not create cache path "
+                    "{}/v/cache/nodeids".format(cache_dir),
+                    '    config.cache.set("cache/nodeids", self.cached_nodeids)',
+                    "*1 failed, 3 warnings in*",
+                ]
             )
         finally:
             testdir.tmpdir.ensure_dir(".pytest_cache").chmod(mode)

testing/test_warnings.py

@@ -712,27 +712,6 @@ class TestStackLevel:
         assert "resultlog.py" in file
         assert func == "pytest_configure"
 
-    def test_issue4445_cacheprovider_set(self, testdir, capwarn):
-        """#4445: Make sure the warning points to a reasonable location
-        See origin of _issue_warning_captured at: _pytest.cacheprovider.py:59
-        """
-        testdir.tmpdir.join(".pytest_cache").write("something wrong")
-        testdir.runpytest(plugins=[capwarn()])
-
-        # with stacklevel=3 the warning originates from one stacklevel above
-        # _issue_warning_captured in cacheprovider.Cache.set and is thrown
-        # when there are errors during cache folder creation
-
-        # set is called twice (in module stepwise and in cacheprovider) so emits
-        # two warnings when there are errors during cache folder creation. (is this intentional?)
-        assert len(capwarn.captured) == 2
-        warning, location = capwarn.captured.pop()
-        file, lineno, func = location
-
-        assert "could not create cache path" in str(warning.message)
-        assert "cacheprovider.py" in file
-        assert func == "set"
-
     def test_issue4445_issue5928_mark_generator(self, testdir):
         """#4445 and #5928: Make sure the warning from an unknown mark points to
         the test file where this mark is used.