Use the modern way to load modules by file name.

Python 3.10 finally got super-noisy about load_module, which has been
deprecated since 3.4!

https://docs.python.org/3/library/importlib.html#importlib.abc.Loader.load_module

Author: nedbat

coverage/backward.py

@@ -245,15 +245,17 @@ def import_local_file(modname, modfile=None):
 
     """
     try:
-        from importlib.machinery import SourceFileLoader
+        import importlib.util as importlib_util
     except ImportError:
-        SourceFileLoader = None
+        importlib_util = None
 
     if modfile is None:
         modfile = modname + '.py'
-    if SourceFileLoader:
-        # pylint: disable=no-value-for-parameter, deprecated-method
-        mod = SourceFileLoader(modname, modfile).load_module()
+    if importlib_util:
+        spec = importlib_util.spec_from_file_location(modname, modfile)
+        mod = importlib_util.module_from_spec(spec)
+        sys.modules[modname] = mod
+        spec.loader.exec_module(mod)
     else:
         for suff in imp.get_suffixes():                 # pragma: part covered
             if suff[0] == '.py':

setup.cfg

@@ -2,10 +2,12 @@
 addopts = -q -n3 --strict --force-flaky --no-flaky-report -rfe --failed-first
 markers =
     expensive: too slow to run during "make smoke"
-# How come this warning is suppressed successfully here, but not in conftest.py??
+
+# How come these warnings are suppressed successfully here, but not in conftest.py??
 filterwarnings =
     ignore:dns.hash module will be removed:DeprecationWarning
     ignore:Using or importing the ABCs:DeprecationWarning
+
 # xfail tests that pass should fail the test suite
 xfail_strict=true
 

tests/conftest.py

@@ -25,21 +25,32 @@ def set_warnings():
     warnings.simplefilter("default")
     warnings.simplefilter("once", DeprecationWarning)
 
-    # A warning to suppress:
+    # Warnings to suppress:
+    # How come these warnings are successfully suppressed here, but not in setup.cfg??
+
     #   setuptools/py33compat.py:54: DeprecationWarning: The value of convert_charrefs will become
     #   True in 3.5. You are encouraged to set the value explicitly.
     #       unescape = getattr(html, 'unescape', html_parser.HTMLParser().unescape)
-    # How come this warning is successfully suppressed here, but not in setup.cfg??
     warnings.filterwarnings(
         "ignore",
         category=DeprecationWarning,
-        message="The value of convert_charrefs will become True in 3.5.",
+        message=r"The value of convert_charrefs will become True in 3.5.",
         )
+
     warnings.filterwarnings(
         "ignore",
         category=DeprecationWarning,
-        message=".* instead of inspect.getfullargspec",
+        message=r".* instead of inspect.getfullargspec",
         )
+
+    # <frozen importlib._bootstrap>:681:
+    # ImportWarning: VendorImporter.exec_module() not found; falling back to load_module()
+    warnings.filterwarnings(
+        "ignore",
+        category=ImportWarning,
+        message=r".*exec_module\(\) not found; falling back to load_module\(\)",
+        )
+
     if env.PYPY3:
         # pypy3 warns about unclosed files a lot.
         warnings.filterwarnings("ignore", r".*unclosed file", category=ResourceWarning)