# Buggy code
def _replace(self, value, name=None, section_name=None, crossonly=False):
    if "{" not in value:
        return value

    section_name = section_name if section_name else self.section_name
    self._subststack.append((section_name, name))
    try:
        replaced = Replacer(self, crossonly=crossonly).do_replace(value)
        assert self._subststack.pop() == (section_name, name)
    except tox.exception.MissingSubstitution:
        if not section_name.startswith(testenvprefix):
            raise tox.exception.ConfigError(
                "substitution env:{!r}: unknown or recursive definition in"
                " section {!r}.".format(value, section_name),
            )
        raise
    return replaced


# Traceback (AttributeError)
tox -vv
using tox.ini: /home/jayvdb/projects/tox/my-tox-tests/tests/tox.ini (pid 23538)
removing /home/jayvdb/projects/tox/my-tox-tests/tests/.tox/log
[wikimedia] tox-wikimedia is enabled
Traceback (most recent call last):
File "/home/jayvdb/.cache/tox/my-tox-tests/py38-tox3_20-other/bin/tox", line 8, in <module>
sys.exit(cmdline())
File "/home/jayvdb/.cache/tox/my-tox-tests/py38-tox3_20-other/lib/python3.8/site-packages/tox/session/__init__.py", line 44, in cmdline
main(args)
File "/home/jayvdb/.cache/tox/my-tox-tests/py38-tox3_20-other/lib/python3.8/site-packages/tox/session/__init__.py", line 65, in main
config = load_config(args)
File "/home/jayvdb/.cache/tox/my-tox-tests/py38-tox3_20-other/lib/python3.8/site-packages/tox/session/__init__.py", line 81, in load_config
config = parseconfig(args)
File "/home/jayvdb/.cache/tox/my-tox-tests/py38-tox3_20-other/lib/python3.8/site-packages/tox/config/__init__.py", line 281, in parseconfig
pm.hook.tox_configure(config=config)  # post process config object
File "/home/jayvdb/.cache/tox/my-tox-tests/py38-tox3_20-other/lib/python3.8/site-packages/pluggy/hooks.py", line 286, in __call__
return self._hookexec(self, self.get_hookimpls(), kwargs)
File "/home/jayvdb/.cache/tox/my-tox-tests/py38-tox3_20-other/lib/python3.8/site-packages/pluggy/manager.py", line 93, in _hookexec
return self._inner_hookexec(hook, methods, kwargs)
File "/home/jayvdb/.cache/tox/my-tox-tests/py38-tox3_20-other/lib/python3.8/site-packages/pluggy/manager.py", line 84, in <lambda>
self._inner_hookexec = lambda hook, methods, kwargs: hook.multicall(
File "/home/jayvdb/.cache/tox/my-tox-tests/py38-tox3_20-other/lib/python3.8/site-packages/pluggy/callers.py", line 208, in _multicall
return outcome.get_result()
File "/home/jayvdb/.cache/tox/my-tox-tests/py38-tox3_20-other/lib/python3.8/site-packages/pluggy/callers.py", line 80, in get_result
raise ex[1].with_traceback(ex[2])
File "/home/jayvdb/.cache/tox/my-tox-tests/py38-tox3_20-other/lib/python3.8/site-packages/pluggy/callers.py", line 187, in _multicall
res = hook_impl.function(*args)
File "/home/jayvdb/.cache/tox/my-tox-tests/py38-tox3_20-other/lib/python3.8/site-packages/tox_wikimedia/__init__.py", line 93, in tox_configure
if dep in cdep.name:
AttributeError: 'str' object has no attribute 'name'

# Fixed code
def _replace(self, value, name=None, section_name=None, crossonly=False):
    if "{" not in value:
        return value

    section_name = section_name if section_name else self.section_name
    assert name
    self._subststack.append((section_name, name))
    try:
        replaced = Replacer(self, crossonly=crossonly).do_replace(value)
        assert self._subststack.pop() == (section_name, name)
    except tox.exception.MissingSubstitution:
        if not section_name.startswith(testenvprefix):
            raise tox.exception.ConfigError(
                "substitution env:{!r}: unknown or recursive definition in"
                " section {!r}.".format(value, section_name),
            )
        raise
    return replaced