setuptools: [BUG] performance after switching to nspektr / importlib_metadata as cratered

Here’s a test:

 setuptools/tests/test_easy_install.py | 66 +++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)

diff --git i/setuptools/tests/test_easy_install.py w/setuptools/tests/test_easy_install.py
index 246d634f2..286af292d 100644
--- i/setuptools/tests/test_easy_install.py
+++ w/setuptools/tests/test_easy_install.py
@@ -890,6 +890,72 @@ class TestSetupRequires:
                 monkeypatch.setenv(str('PIP_TIMEOUT'), str('0'))
                 run_setup(test_setup_py, [str('--version')])
 
+    def test_setup_requires_with_distutils_command_dep(self, monkeypatch):
+
+        with contexts.save_pkg_resources_state():
+            with contexts.tempdir() as temp_dir:
+                # Create source distribution for `extra_dep`.
+                make_sdist(os.path.join(temp_dir, 'extra_dep-1.0.tar.gz'), [
+                    ('setup.py',
+                     DALS("""
+                          import setuptools
+                          setuptools.setup(
+                              name='extra_dep',
+                              version='1.0',
+                              py_modules=['extra_dep'],
+                          )
+                          """)),
+                    ('setup.cfg', ''),
+                    ('extra_dep.py', ''),
+                ])
+                # Create source tree for `epdep`.
+                dep_pkg = os.path.join(temp_dir, 'epdep')
+                os.mkdir(dep_pkg)
+                path.build({
+                    'setup.py':
+                    DALS("""
+                          import setuptools
+                          setuptools.setup(
+                              name='dep', version='2.0',
+                              py_modules=['epcmd'],
+                              extras_require={'extra': ['extra_dep']},
+                              entry_points='''
+                                           [distutils.commands]
+                                           epcmd = epcmd:epcmd [extra]
+                                           ''',
+                          )
+                         """),
+                    'setup.cfg': '',
+                    'epcmd.py': DALS("""
+                                     from distutils.command.build_py import build_py
+
+                                     import extra_dep
+
+                                     class epcmd(build_py):
+                                         pass
+                                     """),
+                }, prefix=dep_pkg)
+                # "Install" dep.
+                run_setup(
+                    os.path.join(dep_pkg, 'setup.py'), [str('dist_info')])
+                working_set.add_entry(dep_pkg)
+                # Create source tree for test package.
+                test_pkg = os.path.join(temp_dir, 'test_pkg')
+                test_setup_py = os.path.join(test_pkg, 'setup.py')
+                os.mkdir(test_pkg)
+                with open(test_setup_py, 'w') as fp:
+                    fp.write(DALS(
+                        '''
+                        from setuptools import installer, setup
+                        setup(setup_requires='dep')
+                        '''))
+                # Check...
+                monkeypatch.setenv(str('PIP_FIND_LINKS'), str(temp_dir))
+                monkeypatch.setenv(str('PIP_NO_INDEX'), str('1'))
+                monkeypatch.setenv(str('PIP_RETRIES'), str('0'))
+                monkeypatch.setenv(str('PIP_TIMEOUT'), str('0'))
+                run_setup(test_setup_py, ['epcmd'])
+
 
 def make_trivial_sdist(dist_path, distname, version):
     """

Which does not pass in v62.6.0 because the code forgets to activate the egg:

 setuptools/dist.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git i/setuptools/dist.py w/setuptools/dist.py
index c1ad30080..79905ed89 100644
--- i/setuptools/dist.py
+++ w/setuptools/dist.py
@@ -926,9 +926,12 @@ class Distribution(_Distribution):
         Given an entry point, ensure that any declared extras for
         its distribution are installed.
         """
+        if not ep.extras:
+            return
         for req in nspektr.missing(ep):
             # fetch_build_egg expects pkg_resources.Requirement
-            self.fetch_build_egg(pkg_resources.Requirement(str(req)))
+            dist = self.fetch_build_egg(pkg_resources.Requirement(str(req)))
+            sys.path.insert(0, dist.location)
 
     def get_egg_cache_dir(self):
         egg_cache_dir = os.path.join(os.curdir, '.eggs')

Going back to v60.9.3, the code is also buggy:

 setuptools/dist.py | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git i/setuptools/dist.py w/setuptools/dist.py
index e825785e2..3a02a61cc 100644
--- i/setuptools/dist.py
+++ w/setuptools/dist.py
@@ -876,23 +876,28 @@ class Distribution(_Distribution):
         Given an entry point, ensure that any declared extras for
         its distribution are installed.
         """
+        if not ep.extras:
+            return
         reqs = {
             req
             for req in map(requirements.Requirement, always_iterable(ep.dist.requires))
-            for extra in ep.extras
-            if extra in req.extras
+            if req.marker is not None and any(
+                req.marker.evaluate({'extra': extra})
+                for extra in ep.extras
+            )
         }
         missing = itertools.filterfalse(self._is_installed, reqs)
         for req in missing:
             # fetch_build_egg expects pkg_resources.Requirement
-            self.fetch_build_egg(pkg_resources.Requirement(str(req)))
+            dist = self.fetch_build_egg(pkg_resources.Requirement(str(req)))
+            sys.path.insert(0, dist.location)
 
     def _is_installed(self, req):
         try:
             dist = metadata.distribution(req.name)
         except metadata.PackageNotFoundError:
             return False
-        found_ver = packaging.version.Version(dist.version())
+        found_ver = packaging.version.Version(dist.version)
         return found_ver in req.specifier
 
     def get_egg_cache_dir(self):

v60.7.1 works as expected. But again, I think the onus should be on the package developer to ensure setup_requires is consistent. The example should be amended:

-                        setup(setup_requires='dep')
+                        setup(setup_requires='dep[extra]')

(which works as expected in v60.7.1, v60.9.3, and v62.6.0)

And _install_requires’ code and corresponding calls can just be removed.

I use entry points with extras, there’s nothing wrong with that.

I think the check for an entrypoint missing dependency is not strictly necessary, and can be dropped: it’s the package developer responsibility to ensure that setup_requires is consistent.

It looks like we don’t have a test for this behavior.

OK, so the old code would use ep.require(installer=self.fetch_build_egg). That’s from 2005 (v0.6a0!), just before adding support for setup_requires in v0.6a1. So again, I’m not even sure it’s needed.