WIP: -p attempts to load setuptools first

Author: nicoddemus

src/_pytest/config/__init__.py

@@ -521,22 +521,29 @@ def import_plugin(self, modname):
         modname = str(modname)
         if self.is_blocked(modname) or self.get_plugin(modname) is not None:
             return
-        if modname in builtin_plugins:
-            importspec = "_pytest." + modname
-        else:
-            importspec = modname
+
+        importspec = "_pytest." + modname if modname in builtin_plugins else modname
         self.rewrite_hook.mark_rewrite(importspec)
+
+        attempt_entry_point = modname not in builtin_plugins
+        if attempt_entry_point:
+            infos = len(self.list_plugin_distinfo())
+            new_infos = self.load_setuptools_entrypoints("pytest11", name=modname)
+            loaded = new_infos > infos
+            if loaded:
+                return
+
         try:
             __import__(importspec)
         except ImportError as e:
-            new_exc_type = ImportError
             new_exc_message = 'Error importing plugin "%s": %s' % (
                 modname,
                 safe_str(e.args[0]),
             )
-            new_exc = new_exc_type(new_exc_message)
+            new_exc = ImportError(new_exc_message)
+            tb = sys.exc_info()[2]
 
-            six.reraise(new_exc_type, new_exc, sys.exc_info()[2])
+            six.reraise(ImportError, new_exc, tb)
 
         except Skipped as e:
             from _pytest.warnings import _issue_warning_captured

testing/acceptance_test.py

@@ -8,6 +8,7 @@
 import textwrap
 import types
 
+import attr
 import py
 import six
 
@@ -108,6 +109,60 @@ def test_option(pytestconfig):
         assert result.ret == 0
         result.stdout.fnmatch_lines(["*1 passed*"])
 
+    @pytest.mark.parametrize("load_cov_early", [True, False])
+    def test_early_load_setuptools_name(self, testdir, monkeypatch, load_cov_early):
+        pkg_resources = pytest.importorskip("pkg_resources")
+
+        testdir.makepyfile(mytestplugin1_module="")
+        testdir.makepyfile(mytestplugin2_module="")
+        testdir.makepyfile(mycov_module="")
+        testdir.syspathinsert()
+
+        loaded = []
+
+        @attr.s
+        class DummyEntryPoint(object):
+            name = attr.ib()
+            module = attr.ib()
+            version = "1.0"
+
+            @property
+            def project_name(self):
+                return self.name
+
+            def load(self):
+                __import__(self.module)
+                loaded.append(self.name)
+                return sys.modules[self.module]
+
+            @property
+            def dist(self):
+                return self
+
+            def _get_metadata(self, *args):
+                return []
+
+        entry_points = [
+            DummyEntryPoint("myplugin1", "mytestplugin1_module"),
+            DummyEntryPoint("myplugin2", "mytestplugin2_module"),
+            DummyEntryPoint("mycov", "mycov_module"),
+        ]
+
+        def my_iter(group, name=None):
+            assert group == "pytest11"
+            for ep in entry_points:
+                if name is not None and ep.name != name:
+                    continue
+                yield ep
+
+        monkeypatch.setattr(pkg_resources, "iter_entry_points", my_iter)
+        params = ("-p", "mycov") if load_cov_early else ()
+        testdir.runpytest_inprocess(*params)
+        if load_cov_early:
+            assert loaded == ["mycov", "myplugin1", "myplugin2"]
+        else:
+            assert loaded == ["myplugin1", "myplugin2", "mycov"]
+
     def test_assertion_magic(self, testdir):
         p = testdir.makepyfile(
             """