Merge branch 'importlib_metadata' into 'master'

Switch from entrypoints to importlib_metadata

Closes #569

See merge request pycqa/flake8!388

setup.cfg

@@ -41,7 +41,6 @@ install_requires=
 # http://flake8.pycqa.org/en/latest/faq.html#why-does-flake8-use-ranges-for-its-dependencies
 # And in which releases we will update those ranges here:
 # http://flake8.pycqa.org/en/latest/internal/releases.html#releasing-flake8
-    entrypoints >= 0.3.0, < 0.4.0
     pyflakes >= 2.1.0, < 2.2.0
     pycodestyle >= 2.5.0, < 2.6.0
     mccabe >= 0.6.0, < 0.7.0
@@ -49,6 +48,7 @@ install_requires=
     typing; python_version<"3.5"
     configparser; python_version<"3.2"
     functools32; python_version<"3.2"
+    importlib-metadata; python_version<"3.8"
 
 python_requires = >=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*
 

src/flake8/_compat.py

@@ -0,0 +1,14 @@
+"""Expose backports in a single place."""
+import sys
+
+if sys.version_info >= (3,):  # pragma: no cover (PY3+)
+    from functools import lru_cache
+else:  # pragma: no cover (<PY3)
+    from functools32 import lru_cache
+
+if sys.version_info >= (3, 8):  # pragma: no cover (PY38+)
+    import importlib.metadata as importlib_metadata
+else:  # pragma: no cover (<PY38)
+    import importlib_metadata
+
+__all__ = ("lru_cache", "importlib_metadata")

src/flake8/exceptions.py

@@ -1,10 +1,6 @@
 """Exception classes for all of Flake8."""
-
 from typing import Dict
 
-if False:  # `typing.TYPE_CHECKING` was introduced in 3.5.2
-    from flake8.plugins.manager import Plugin
-
 
 class Flake8Exception(Exception):
     """Plain Flake8 exception."""
@@ -23,18 +19,17 @@ class FailedToLoadPlugin(Flake8Exception):
 
     FORMAT = 'Flake8 failed to load plugin "%(name)s" due to %(exc)s.'
 
-    def __init__(self, plugin, exception):
-        # type: (Plugin, Exception) -> None
+    def __init__(self, plugin_name, exception):
+        # type: (str, Exception) -> None
         """Initialize our FailedToLoadPlugin exception."""
-        self.plugin = plugin
-        self.ep_name = self.plugin.name
+        self.plugin_name = plugin_name
         self.original_exception = exception
-        super(FailedToLoadPlugin, self).__init__(plugin, exception)
+        super(FailedToLoadPlugin, self).__init__(plugin_name, exception)
 
     def __str__(self):  # type: () -> str
         """Format our exception message."""
         return self.FORMAT % {
-            "name": self.ep_name,
+            "name": self.plugin_name,
             "exc": self.original_exception,
         }
 

src/flake8/main/application.py

@@ -168,9 +168,7 @@ class Application(object):
 
         sys.path.extend(local_plugins.paths)
 
-        self.check_plugins = plugin_manager.Checkers(
-            local_plugins.extension
-        )
+        self.check_plugins = plugin_manager.Checkers(local_plugins.extension)
 
         self.formatting_plugins = plugin_manager.ReportFormatters(
             local_plugins.report

src/flake8/main/debug.py

@@ -4,8 +4,7 @@ from __future__ import print_function
 import argparse
 import json
 import platform
-
-import entrypoints
+from typing import Dict, List
 
 
 class DebugAction(argparse.Action):
@@ -61,6 +60,6 @@ def plugins_from(option_manager):
     ]
 
 
-def dependencies():
+def dependencies():  # type: () -> List[Dict[str, str]]
     """Generate the list of dependencies we care about."""
-    return [{"dependency": "entrypoints", "version": entrypoints.__version__}]
+    return []

src/flake8/plugins/manager.py

@@ -2,10 +2,9 @@
 import logging
 from typing import Any, Dict, List, Optional, Set
 
-import entrypoints
-
 from flake8 import exceptions
 from flake8 import utils
+from flake8._compat import importlib_metadata
 
 LOG = logging.getLogger(__name__)
 
@@ -159,7 +158,7 @@ class Plugin(object):
             except Exception as load_exception:
                 LOG.exception(load_exception)
                 failed_to_load = exceptions.FailedToLoadPlugin(
-                    plugin=self, exception=load_exception
+                    plugin_name=self.name, exception=load_exception
                 )
                 LOG.critical(str(failed_to_load))
                 raise failed_to_load
@@ -224,6 +223,7 @@ class PluginManager(object):  # pylint: disable=too-few-public-methods
     """Find and manage plugins consistently."""
 
     def __init__(self, namespace, local_plugins=None):
+        # type: (str, Optional[List[str]]) -> None
         """Initialize the manager.
 
         :param str namespace:
@@ -246,12 +246,16 @@ class PluginManager(object):  # pylint: disable=too-few-public-methods
         for plugin_str in local_plugins:
             name, _, entry_str = plugin_str.partition("=")
             name, entry_str = name.strip(), entry_str.strip()
-            entry_point = entrypoints.EntryPoint.from_string(entry_str, name)
+            entry_point = importlib_metadata.EntryPoint(name, entry_str, None)
             self._load_plugin_from_entrypoint(entry_point, local=True)
 
     def _load_entrypoint_plugins(self):
         LOG.info('Loading entry-points for "%s".', self.namespace)
-        for entry_point in entrypoints.get_group_all(self.namespace):
+        eps = importlib_metadata.entry_points().get(self.namespace, ())
+        # python2.7 occasionally gives duplicate results due to redundant
+        # `local/lib` -> `../lib` symlink on linux in virtualenvs so we
+        # eliminate duplicates here
+        for entry_point in sorted(frozenset(eps)):
             if entry_point.name == "per-file-ignores":
                 LOG.warning(
                     "flake8-per-file-ignores plugin is incompatible with "

src/flake8/style_guide.py

@@ -7,13 +7,13 @@ import enum
 import itertools
 import linecache
 import logging
-import sys
 from typing import Dict, Generator, List, Match, Optional, Sequence, Set
 from typing import Tuple, Union
 
 from flake8 import defaults
 from flake8 import statistics
 from flake8 import utils
+from flake8._compat import lru_cache
 from flake8.formatting import base as base_formatter
 
 __all__ = ("StyleGuide",)
@@ -21,12 +21,6 @@ __all__ = ("StyleGuide",)
 LOG = logging.getLogger(__name__)
 
 
-if sys.version_info < (3, 2):
-    from functools32 import lru_cache
-else:
-    from functools import lru_cache
-
-
 class Selected(enum.Enum):
     """Enum representing an explicitly or implicitly selected code."""
 

tests/integration/test_checker.py

@@ -3,6 +3,7 @@ import mock
 import pytest
 
 from flake8 import checker
+from flake8._compat import importlib_metadata
 from flake8.plugins import manager
 
 PHYSICAL_LINE = "# Physical line content"
@@ -100,7 +101,11 @@ def mock_file_checker_with_plugin(plugin_target):
     entry_point.load.return_value = plugin_target
 
     # Load the checker plugins using the entry point mock
-    with mock.patch('entrypoints.get_group_all', return_value=[entry_point]):
+    with mock.patch.object(
+            importlib_metadata,
+            'entry_points',
+            return_value={'flake8.extension': [entry_point]},
+    ):
         checks = manager.Checkers()
 
     # Prevent it from reading lines from stdin or somewhere else

tests/unit/test_debug.py

@@ -1,5 +1,4 @@
 """Tests for our debugging module."""
-import entrypoints
 import mock
 import pytest
 
@@ -9,9 +8,7 @@ from flake8.options import manager
 
 def test_dependencies():
     """Verify that we format our dependencies appropriately."""
-    expected = [{'dependency': 'entrypoints',
-                 'version': entrypoints.__version__}]
-    assert expected == debug.dependencies()
+    assert [] == debug.dependencies()
 
 
 @pytest.mark.parametrize('plugins, expected', [
@@ -46,8 +43,7 @@ def test_information(system, pyversion, pyimpl):
                      'is_local': False},
                     {'plugin': 'pycodestyle', 'version': '2.0.0',
                      'is_local': False}],
-        'dependencies': [{'dependency': 'entrypoints',
-                          'version': entrypoints.__version__}],
+        'dependencies': [],
         'platform': {
             'python_implementation': 'CPython',
             'python_version': '3.5.3',

tests/unit/test_exceptions.py

@@ -1,10 +1,7 @@
 """Tests for the flake8.exceptions module."""
 import pickle
 
-import entrypoints
-
 from flake8 import exceptions
-from flake8.plugins import manager as plugins_manager
 
 
 class _ExceptionTest:
@@ -22,10 +19,7 @@ class TestFailedToLoadPlugin(_ExceptionTest):
     """Tests for the FailedToLoadPlugin exception."""
 
     err = exceptions.FailedToLoadPlugin(
-        plugin=plugins_manager.Plugin(
-            'plugin_name',
-            entrypoints.EntryPoint('plugin_name', 'os.path', None),
-        ),
+        plugin_name='plugin_name',
         exception=ValueError('boom!'),
     )
 

tests/unit/test_plugin_manager.py

@@ -1,62 +1,58 @@
 """Tests for flake8.plugins.manager.PluginManager."""
 import mock
 
+from flake8._compat import importlib_metadata
 from flake8.plugins import manager
 
 
-def create_entry_point_mock(name):
-    """Create a mocked EntryPoint."""
-    ep = mock.Mock(spec=['name'])
-    ep.name = name
-    return ep
-
-
-@mock.patch('entrypoints.get_group_all')
-def test_calls_entrypoints_on_instantiation(get_group_all):
-    """Verify that we call get_group_all when we create a manager."""
-    get_group_all.return_value = []
+@mock.patch.object(importlib_metadata, 'entry_points')
+def test_calls_entrypoints_on_instantiation(entry_points_mck):
+    """Verify that we call entry_points() when we create a manager."""
+    entry_points_mck.return_value = {}
     manager.PluginManager(namespace='testing.entrypoints')
-
-    get_group_all.assert_called_once_with('testing.entrypoints')
+    entry_points_mck.assert_called_once_with()
 
 
-@mock.patch('entrypoints.get_group_all')
-def test_calls_entrypoints_creates_plugins_automaticaly(get_group_all):
+@mock.patch.object(importlib_metadata, 'entry_points')
+def test_calls_entrypoints_creates_plugins_automaticaly(entry_points_mck):
     """Verify that we create Plugins on instantiation."""
-    get_group_all.return_value = [
-        create_entry_point_mock('T100'),
-        create_entry_point_mock('T200'),
-    ]
+    entry_points_mck.return_value = {
+        'testing.entrypoints': [
+            importlib_metadata.EntryPoint('T100', '', None),
+            importlib_metadata.EntryPoint('T200', '', None),
+        ],
+    }
     plugin_mgr = manager.PluginManager(namespace='testing.entrypoints')
 
-    get_group_all.assert_called_once_with('testing.entrypoints')
+    entry_points_mck.assert_called_once_with()
     assert 'T100' in plugin_mgr.plugins
     assert 'T200' in plugin_mgr.plugins
     assert isinstance(plugin_mgr.plugins['T100'], manager.Plugin)
     assert isinstance(plugin_mgr.plugins['T200'], manager.Plugin)
 
 
-@mock.patch('entrypoints.get_group_all')
-def test_handles_mapping_functions_across_plugins(get_group_all):
+@mock.patch.object(importlib_metadata, 'entry_points')
+def test_handles_mapping_functions_across_plugins(entry_points_mck):
     """Verify we can use the PluginManager call functions on all plugins."""
-    entry_point_mocks = [
-        create_entry_point_mock('T100'),
-        create_entry_point_mock('T200'),
-    ]
-    get_group_all.return_value = entry_point_mocks
+    entry_points_mck.return_value = {
+        'testing.entrypoints': [
+            importlib_metadata.EntryPoint('T100', '', None),
+            importlib_metadata.EntryPoint('T200', '', None),
+        ],
+    }
     plugin_mgr = manager.PluginManager(namespace='testing.entrypoints')
     plugins = [plugin_mgr.plugins[name] for name in plugin_mgr.names]
 
     assert list(plugin_mgr.map(lambda x: x)) == plugins
 
 
-@mock.patch('entrypoints.get_group_all')
-def test_local_plugins(get_group_all):
+@mock.patch.object(importlib_metadata, 'entry_points')
+def test_local_plugins(entry_points_mck):
     """Verify PluginManager can load given local plugins."""
-    get_group_all.return_value = []
+    entry_points_mck.return_value = {}
     plugin_mgr = manager.PluginManager(
         namespace='testing.entrypoints',
         local_plugins=['X = path.to:Plugin']
     )
 
-    assert plugin_mgr.plugins['X'].entry_point.module_name == 'path.to'
+    assert plugin_mgr.plugins['X'].entry_point.value == 'path.to:Plugin'

tests/unit/test_plugin_type_manager.py

@@ -13,7 +13,7 @@ def create_plugin_mock(raise_exception=False):
     plugin = mock.create_autospec(manager.Plugin, instance=True)
     if raise_exception:
         plugin.load_plugin.side_effect = exceptions.FailedToLoadPlugin(
-            plugin=mock.Mock(name='T101'),
+            plugin_name='T101',
             exception=ValueError('Test failure'),
         )
     return plugin