[4.6] Replace importlib_metadata with importlib.metadata on Python 3.8+ (#5539)

changelog/5523.bugfix.rst

@@ -0,0 +1 @@
+Fixed using multiple short options together in the command-line (for example ``-vs``) in Python 3.8+.

changelog/5537.bugfix.rst

@@ -0,0 +1,2 @@
+Replace ``importlib_metadata`` backport with ``importlib.metadata`` from the
+standard library on Python 3.8+.

setup.py

@@ -15,7 +15,7 @@
     'pathlib2>=2.2.0;python_version<"3.6"',
     'colorama;sys_platform=="win32"',
     "pluggy>=0.12,<1.0",
-    "importlib-metadata>=0.12",
+    'importlib-metadata>=0.12;python_version<"3.8"',
     "wcwidth",
 ]
 

src/_pytest/compat.py

@@ -62,6 +62,12 @@ def spec_from_file_location(*_, **__):
         return None
 
 
+if sys.version_info >= (3, 8):
+    from importlib import metadata as importlib_metadata  # noqa
+else:
+    import importlib_metadata  # noqa
+
+
 def _format_args(func):
     return str(signature(func))
 

src/_pytest/config/__init__.py

@@ -13,7 +13,6 @@
 import types
 import warnings
 
-import importlib_metadata
 import py
 import six
 from packaging.version import Version
@@ -31,6 +30,7 @@
 from _pytest import deprecated
 from _pytest._code import ExceptionInfo
 from _pytest._code import filter_traceback
+from _pytest.compat import importlib_metadata
 from _pytest.compat import lru_cache
 from _pytest.compat import safe_str
 from _pytest.outcomes import fail

testing/acceptance_test.py

@@ -9,11 +9,11 @@
 import types
 
 import attr
-import importlib_metadata
 import py
 import six
 
 import pytest
+from _pytest.compat import importlib_metadata
 from _pytest.main import EXIT_NOTESTSCOLLECTED
 from _pytest.main import EXIT_USAGEERROR
 from _pytest.warnings import SHOW_PYTEST_WARNINGS_ARG

testing/test_assertion.py

@@ -180,7 +180,8 @@ def check(values, value):
                 return check
             """,
             "mainwrapper.py": """\
-            import pytest, importlib_metadata
+            import pytest
+            from _pytest.compat import importlib_metadata
 
             class DummyEntryPoint(object):
                 name = 'spam'

testing/test_config.py

@@ -6,10 +6,9 @@
 import sys
 import textwrap
 
-import importlib_metadata
-
 import _pytest._code
 import pytest
+from _pytest.compat import importlib_metadata
 from _pytest.config import _iter_rewritable_modules
 from _pytest.config.exceptions import UsageError
 from _pytest.config.findpaths import determine_setup

testing/test_entry_points.py

@@ -3,7 +3,7 @@
 from __future__ import division
 from __future__ import print_function
 
-import importlib_metadata
+from _pytest.compat import importlib_metadata
 
 
 def test_pytest_entry_points_are_identical():