Revert "Switch to importlib-metadata"

changelog/205.bugfix.rst

@@ -0,0 +1 @@
+Revert changes made in 0.10.0 release breaking ``.egg`` installs.

docs/conf.py

@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-import importlib_metadata
+import pkg_resources
 
 
 extensions = [
@@ -20,13 +20,14 @@
 
 # General information about the project.
 
-project = "pluggy"
+dist = pkg_resources.get_distribution("pluggy")
+project = dist.project_name
 copyright = u"2016, Holger Krekel"
 author = "Holger Krekel"
 
-release = importlib_metadata.version(project)
+release = dist.version
 # The short X.Y version.
-version = u".".join(release.split(".")[:2])
+version = u".".join(dist.version.split(".")[:2])
 
 
 language = None

pluggy/manager.py

@@ -3,8 +3,6 @@
 from .hooks import HookImpl, _HookRelay, _HookCaller, normalize_hookimpl_opts
 import warnings
 
-import importlib_metadata
-
 
 def _warn_for_function(warning, function):
     warnings.warn_explicit(
@@ -27,23 +25,6 @@ def __init__(self, plugin, message):
         super(Exception, self).__init__(message)
 
 
-class DistFacade(object):
-    """Emulate a pkg_resources Distribution"""
-
-    def __init__(self, dist):
-        self._dist = dist
-
-    @property
-    def project_name(self):
-        return self.metadata["name"]
-
-    def __getattr__(self, attr, default=None):
-        return getattr(self._dist, attr, default)
-
-    def __dir__(self):
-        return sorted(dir(self._dist) + ["_dist", "project_name"])
-
-
 class PluginManager(object):
     """ Core Pluginmanager class which manages registration
     of plugin objects and 1:N hook calling.
@@ -278,18 +259,29 @@ def load_setuptools_entrypoints(self, group, name=None):
         :rtype: int
         :return: return the number of loaded plugins by this call.
         """
+        from pkg_resources import (
+            iter_entry_points,
+            DistributionNotFound,
+            VersionConflict,
+        )
+
         count = 0
-        for dist in importlib_metadata.distributions():
-            for ep in dist.entry_points:
-                if ep.group != group or (name is not None and ep.name != name):
-                    continue
-                # is the plugin registered or blocked?
-                if self.get_plugin(ep.name) or self.is_blocked(ep.name):
-                    continue
+        for ep in iter_entry_points(group, name=name):
+            # is the plugin registered or blocked?
+            if self.get_plugin(ep.name) or self.is_blocked(ep.name):
+                continue
+            try:
                 plugin = ep.load()
-                self.register(plugin, name=ep.name)
-                self._plugin_distinfo.append((plugin, DistFacade(dist)))
-                count += 1
+            except DistributionNotFound:
+                continue
+            except VersionConflict as e:
+                raise PluginValidationError(
+                    plugin=None,
+                    message="Plugin %r could not be loaded: %s!" % (ep.name, e),
+                )
+            self.register(plugin, name=ep.name)
+            self._plugin_distinfo.append((plugin, ep.dist))
+            count += 1
         return count
 
     def list_plugin_distinfo(self):

setup.py

@@ -36,7 +36,6 @@ def main():
         author_email="holger@merlinux.eu",
         url="https://github.com/pytest-dev/pluggy",
         python_requires=">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*",
-        install_requires=["importlib-metadata>=0.9"],
         extras_require={"dev": ["pre-commit", "tox"]},
         classifiers=classifiers,
         packages=["pluggy"],

testing/test_pluginmanager.py

@@ -3,7 +3,7 @@
 """
 import pytest
 import types
-import importlib_metadata
+import sys
 from pluggy import (
     PluginManager,
     PluginValidationError,
@@ -447,40 +447,64 @@ def example_hook():
 
 
 def test_load_setuptools_instantiation(monkeypatch, pm):
-    class EntryPoint(object):
-        name = "myname"
-        group = "hello"
-        value = "myname:foo"
+    pkg_resources = pytest.importorskip("pkg_resources")
 
-        def load(self):
-            class PseudoPlugin(object):
-                x = 42
+    def my_iter(group, name=None):
+        assert group == "hello"
 
-            return PseudoPlugin()
+        class EntryPoint(object):
+            name = "myname"
+            dist = None
 
-    class Distribution(object):
-        entry_points = (EntryPoint(),)
+            def load(self):
+                class PseudoPlugin(object):
+                    x = 42
 
-    dist = Distribution()
+                return PseudoPlugin()
 
-    def my_distributions():
-        return (dist,)
+        return iter([EntryPoint()])
 
-    monkeypatch.setattr(importlib_metadata, "distributions", my_distributions)
+    monkeypatch.setattr(pkg_resources, "iter_entry_points", my_iter)
     num = pm.load_setuptools_entrypoints("hello")
     assert num == 1
     plugin = pm.get_plugin("myname")
     assert plugin.x == 42
-    ret = pm.list_plugin_distinfo()
-    # poor man's `assert ret == [(plugin, mock.ANY)]`
-    assert len(ret) == 1
-    assert len(ret[0]) == 2
-    assert ret[0][0] == plugin
-    assert ret[0][1]._dist == dist
+    assert pm.list_plugin_distinfo() == [(plugin, None)]
     num = pm.load_setuptools_entrypoints("hello")
     assert num == 0  # no plugin loaded by this call
 
 
+def test_load_setuptools_version_conflict(monkeypatch, pm):
+    """Check that we properly handle a VersionConflict problem when loading entry points"""
+    pkg_resources = pytest.importorskip("pkg_resources")
+
+    def my_iter(group, name=None):
+        assert group == "hello"
+
+        class EntryPoint(object):
+            name = "myname"
+            dist = None
+
+            def load(self):
+                raise pkg_resources.VersionConflict("Some conflict")
+
+        return iter([EntryPoint()])
+
+    monkeypatch.setattr(pkg_resources, "iter_entry_points", my_iter)
+    with pytest.raises(
+        PluginValidationError,
+        match="Plugin 'myname' could not be loaded: Some conflict!",
+    ):
+        pm.load_setuptools_entrypoints("hello")
+
+
+def test_load_setuptools_not_installed(monkeypatch, pm):
+    monkeypatch.setitem(sys.modules, "pkg_resources", types.ModuleType("pkg_resources"))
+
+    with pytest.raises(ImportError):
+        pm.load_setuptools_entrypoints("qwe")
+
+
 def test_add_tracefuncs(he_pm):
     out = []