Merge branch 'entrypoints' into 'master'

Replace setuptools with entrypoints

See merge request pycqa/flake8!264

3 files changed, 15 insertions, 35 deletions

diff --git a/src/flake8/main/application.py b/src/flake8/main/application.py
index b86b3cc..86d7fd4 100644
--- a/src/flake8/main/application.py
+++ b/src/flake8/main/application.py
@@ -169,7 +169,7 @@ class Application(object):
         If :attr:`check_plugins`, :attr:`listening_plugins`, or
         :attr:`formatting_plugins` are ``None`` then this method will update
         them with the appropriate plugin manager instance. Given the expense
-        of finding plugins (via :mod:`pkg_resources`) we want this to be
+        of finding plugins (via :mod:`entrypoints`) we want this to be
         idempotent and so only update those attributes if they are ``None``.
         """
         if self.local_plugins is None:
@@ -238,16 +238,7 @@ class Application(object):
 
     def formatter_for(self, formatter_plugin_name):
         """Retrieve the formatter class by plugin name."""
-        try:
-            default_formatter = self.formatting_plugins["default"]
-        except KeyError:
-            raise exceptions.ExecutionError(
-                "The 'default' Flake8 formatting plugin is unavailable. "
-                "This usually indicates that your setuptools is too old. "
-                "Please upgrade setuptools. If that does not fix the issue"
-                " please file an issue."
-            )
-
+        default_formatter = self.formatting_plugins["default"]
         formatter_plugin = self.formatting_plugins.get(formatter_plugin_name)
         if formatter_plugin is None:
             LOG.warning(
diff --git a/src/flake8/main/debug.py b/src/flake8/main/debug.py
index 51bac9a..e02da6b 100644
--- a/src/flake8/main/debug.py
+++ b/src/flake8/main/debug.py
@@ -4,6 +4,8 @@ from __future__ import print_function
 import json
 import platform
 
+import entrypoints
+
 
 def print_information(
     option, option_string, value, parser, option_manager=None
@@ -64,7 +66,4 @@ def plugins_from(option_manager):
 
 def dependencies():
     """Generate the list of dependencies we care about."""
-    # defer this expensive import, not used outside --bug-report
-    import setuptools
-
-    return [{"dependency": "setuptools", "version": setuptools.__version__}]
+    return [{"dependency": "entrypoints", "version": entrypoints.__version__}]
diff --git a/src/flake8/plugins/manager.py b/src/flake8/plugins/manager.py
index 6d0cf99..010cfb9 100644
--- a/src/flake8/plugins/manager.py
+++ b/src/flake8/plugins/manager.py
@@ -2,7 +2,7 @@
 import logging
 import sys
 
-import pkg_resources
+import entrypoints
 
 from flake8 import exceptions
 from flake8 import utils
@@ -143,17 +143,8 @@ class Plugin(object):
         r"""Call the plugin with \*args and \*\*kwargs."""
         return self.plugin(*args, **kwargs)  # pylint: disable=not-callable
 
-    def _load(self, verify_requirements):
-        # Avoid relying on hasattr() here.
-        resolve = getattr(self.entry_point, "resolve", None)
-        require = getattr(self.entry_point, "require", None)
-        if resolve and require:
-            if verify_requirements:
-                LOG.debug('Verifying plugin "%s"\'s requirements.', self.name)
-                require()
-            self._plugin = resolve()
-        else:
-            self._plugin = self.entry_point.load(require=verify_requirements)
+    def _load(self):
+        self._plugin = self.entry_point.load()
         if not callable(self._plugin):
             msg = (
                 "Plugin %r is not a callable. It might be written for an"
@@ -171,15 +162,14 @@ class Plugin(object):
         cached plugin.
 
         :param bool verify_requirements:
-            Whether or not to make setuptools verify that the requirements for
-            the plugin are satisfied.
+            Does nothing, retained for backwards compatibility.
         :returns:
             Nothing
         """
         if self._plugin is None:
             LOG.info('Loading plugin "%s" from entry-point.', self.name)
             try:
-                self._load(verify_requirements)
+                self._load()
             except Exception as load_exception:
                 LOG.exception(load_exception)
                 failed_to_load = exceptions.FailedToLoadPlugin(
@@ -256,11 +246,9 @@ class PluginManager(object):  # pylint: disable=too-few-public-methods
         :param list local_plugins:
             Plugins from config (as "X = path.to:Plugin" strings).
         :param bool verify_requirements:
-            Whether or not to make setuptools verify that the requirements for
-            the plugin are satisfied.
+            Does nothing, retained for backwards compatibility.
         """
         self.namespace = namespace
-        self.verify_requirements = verify_requirements
         self.plugins = {}
         self.names = []
         self._load_local_plugins(local_plugins or [])
@@ -273,12 +261,14 @@ class PluginManager(object):  # pylint: disable=too-few-public-methods
             Plugins from config (as "X = path.to:Plugin" strings).
         """
         for plugin_str in local_plugins:
-            entry_point = pkg_resources.EntryPoint.parse(plugin_str)
+            name, _, entry_str = plugin_str.partition("=")
+            name, entry_str = name.strip(), entry_str.strip()
+            entry_point = entrypoints.EntryPoint.from_string(entry_str, name)
             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 pkg_resources.iter_entry_points(self.namespace):
+        for entry_point in entrypoints.get_group_all(self.namespace):
             self._load_plugin_from_entrypoint(entry_point)
 
     def _load_plugin_from_entrypoint(self, entry_point, local=False):