EntryPoint.load(require=True) raises UndefinedEnvironmentName exception if the entry point with extra

[jun66j5]

Originally reported in https://trac.edgewall.org/ticket/13051. PostgreSQL cannot be used due to the issue.

The issue is raised with setuptools 39.2.0 and 40.0.0 but is not raised with setuptools 39.1.0. Another work around is to install tarball (*.egg-info used) rather than Trac wheel package (*.dist-info used).

15:19:45 Trac[loader] DEBUG: Loading plugin "trac.db.postgres" from "/dev/shm/trac-1.2.2/lib/python2.7/site-packages"
15:19:45 Trac[loader] ERROR: Skipping "trac.db.postgres = trac.db.postgres_backend [postgresql]":
Traceback (most recent call last):
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/trac/loader.py", line 68, in _load_eggs
    entry.load(require=True)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 2228, in load
    self.require(*args, **kwargs)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 2245, in require
    items = working_set.resolve(reqs, env, installer)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 808, in resolve
    if not req_extras.markers_pass(req):
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 993, in markers_pass
    return not req.marker or any(extra_evals) or req.marker.evaluate()
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/_vendor/packaging/markers.py", line 278, in evaluate
    return _evaluate_markers(self._markers, current_environment)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/_vendor/packaging/markers.py", line 203, in _evaluate_markers
    lhs_value = _get_env(environment, lhs.value)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/_vendor/packaging/markers.py", line 185, in _get_env
    "{0!r} does not exist in evaluation environment.".format(name)
UndefinedEnvironmentName: 'extra' does not exist in evaluation environment.

setup.py in Trac 1.2.2: https://trac.edgewall.org/browser/tags/trac-1.2.2/setup.py?marks=98,115#L95

How to reproduce:

$ /usr/bin/virtualenv -p /usr/bin/python2.7 /dev/shm/trac-1.2.2
$ source /dev/shm/trac-1.2.2/bin/activate
(trac-1.2.2) $ pip install trac
(trac-1.2.2) $ pip install psycopg2
(trac-1.2.2) $ trac-admin /dev/shm/trac-1.2.2-tracenv initenv 'My Project' 'postgres://tracuser:password@localhost:5432/trac?schema=trac_1_2_2'
Creating and Initializing Project
Initenv for '/dev/shm/trac-1.2.2-tracenv' failed.
Failed to create environment.
Unsupported database type "postgres"
Traceback (most recent call last):
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/trac/admin/console.py", line 500, in do_initenv
    options=options)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/trac/core.py", line 136, in __call__
    self.__init__(*args, **kwargs)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/trac/env.py", line 300, in __init__
    self.create(options)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/trac/env.py", line 592, in create
    DatabaseManager(self).init_db()
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/trac/db/api.py", line 337, in init_db
    connector, args = self.get_connector()
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/trac/db/api.py", line 615, in get_connector
    scheme=scheme))
TracError: Unsupported database type "postgres"
(trac-1.2.2) $ cat > /dev/shm/trac-1.2.2/inherit.ini
[logging]
log_type = stderr
(trac-1.2.2) $ trac-admin /dev/shm/trac-1.2.2-tracenv initenv --inherit=/dev/shm/trac-1.2.2/inherit.ini 'My Project' 'postgres://tracuser:password@localhost:5432/trac?schema=trac_1_2_2'
Creating and Initializing Project
15:19:45 Trac[env] INFO: -------------------------------- environment startup [Trac 1.2.2] --------------------------------
...
15:19:45 Trac[loader] DEBUG: Loading plugin "trac.db.postgres" from "/dev/shm/trac-1.2.2/lib/python2.7/site-packages"
15:19:45 Trac[loader] ERROR: Skipping "trac.db.postgres = trac.db.postgres_backend [postgresql]":
Traceback (most recent call last):
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/trac/loader.py", line 68, in _load_eggs
    entry.load(require=True)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 2228, in load
    self.require(*args, **kwargs)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 2245, in require
    items = working_set.resolve(reqs, env, installer)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 808, in resolve
    if not req_extras.markers_pass(req):
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 993, in markers_pass
    return not req.marker or any(extra_evals) or req.marker.evaluate()
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/_vendor/packaging/markers.py", line 278, in evaluate
    return _evaluate_markers(self._markers, current_environment)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/_vendor/packaging/markers.py", line 203, in _evaluate_markers
    lhs_value = _get_env(environment, lhs.value)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/_vendor/packaging/markers.py", line 185, in _get_env
    "{0!r} does not exist in evaluation environment.".format(name)
UndefinedEnvironmentName: 'extra' does not exist in evaluation environment.
...

See also https://trac.edgewall.org/ticket/13051#comment:3

[jaraco]

Here are the differences between 39.1.0 and 39.2.0.

[jaraco]

I don't see anything in those changes that seems like it should be implicated in the reported failure. Also the egg-info/dist-info distinction doesn't seem right.

We'll want to try to distill down the behavior that causes the failure, probably with a minimal package that exhibits the same behavior, but nothing else.