tox -e expansion seems to parse incorrectly

[tucked]

I'm using tox 4.2.3.

[tox]
[testenv]
deps =
  pytest6.x: pytest~=6.0
  pytest7.x: pytest~=7.0
commands = pytest --version

$ tox -e py38-pytest7.x
py38-pytest7.x: commands[0]> pytest --version
pytest 7.2.0
  py38-pytest7.x: OK (0.57=setup[0.15]+cmd[0.42] seconds)
  congratulations :) (0.87 seconds)

$ tox -e 'py38-pytest{6.x,7.x}'
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/tox_env/api.py", line 248, in setup
    self._setup_env()
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/tox_env/python/runner.py", line 107, in _setup_env
    self._install_deps()
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/tox_env/python/runner.py", line 110, in _install_deps
    requirements_file: PythonDeps = self.conf["deps"]
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/sets.py", line 114, in __getitem__
    return self.load(item)
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/sets.py", line 125, in load
    return config_definition.__call__(self._conf, self.loaders, ConfigLoadArgs(chain, self.name, self.env_name))
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/of_type.py", line 102, in __call__
    value = loader.load(key, self.of_type, self.factory, conf, args)
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/loader/api.py", line 124, in load
    raw = self.load_raw(key, conf, args.env_name)
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/loader/ini/__init__.py", line 42, in load_raw
    return self.process_raw(conf, env_name, self._section_proxy[key])
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/loader/ini/__init__.py", line 56, in process_raw
    factor_filtered = filter_for_env(strip_comments, env_name)  # select matching factors
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/loader/ini/factor.py", line 13, in filter_for_env
    set(chain.from_iterable([(i for i, _ in a) for a in find_factor_groups(name)])) if name is not None else set()
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/loader/ini/factor.py", line 13, in <listcomp>
    set(chain.from_iterable([(i for i, _ in a) for a in find_factor_groups(name)])) if name is not None else set()
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/loader/ini/factor.py", line 65, in find_factor_groups
    for env in expand_env_with_negation(value):
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/loader/ini/factor.py", line 83, in expand_env_with_negation
    raise ValueError(variant_str)
ValueError: py38-pytest{6.x
py38-pytest{6.x: FAIL ✖ in 0.1 seconds
7.x}: internal error
Traceback (most recent call last):
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/session/cmd/run/single.py", line 45, in _evaluate
    tox_env.setup()
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/tox_env/api.py", line 248, in setup
    self._setup_env()
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/tox_env/python/runner.py", line 107, in _setup_env
    self._install_deps()
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/tox_env/python/runner.py", line 110, in _install_deps
    requirements_file: PythonDeps = self.conf["deps"]
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/sets.py", line 114, in __getitem__
    return self.load(item)
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/sets.py", line 125, in load
    return config_definition.__call__(self._conf, self.loaders, ConfigLoadArgs(chain, self.name, self.env_name))
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/of_type.py", line 102, in __call__
    value = loader.load(key, self.of_type, self.factory, conf, args)
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/loader/api.py", line 124, in load
    raw = self.load_raw(key, conf, args.env_name)
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/loader/ini/__init__.py", line 42, in load_raw
    return self.process_raw(conf, env_name, self._section_proxy[key])
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/loader/ini/__init__.py", line 56, in process_raw
    factor_filtered = filter_for_env(strip_comments, env_name)  # select matching factors
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/loader/ini/factor.py", line 13, in filter_for_env
    set(chain.from_iterable([(i for i, _ in a) for a in find_factor_groups(name)])) if name is not None else set()
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/loader/ini/factor.py", line 13, in <listcomp>
    set(chain.from_iterable([(i for i, _ in a) for a in find_factor_groups(name)])) if name is not None else set()
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/loader/ini/factor.py", line 65, in find_factor_groups
    for env in expand_env_with_negation(value):
  File "/ifs/home/dtucker/.local/pipx/venvs/tox/lib/python3.8/site-packages/tox/config/loader/ini/factor.py", line 83, in expand_env_with_negation
    raise ValueError(variant_str)
ValueError: 7.x}
  py38-pytest{6.x: FAIL code 2 (0.10 seconds)
  7.x}: FAIL code 2 (0.01 seconds)
  evaluation failed :( (0.25 seconds)

[gaborbernat]

PR welcome.

[Jajauma]

At the same time parsing envlist in tox.ini seems to work correctly. The override option can be used as a workaround, e.g.:

tox run -x 'tox.envlist=py{x,y,z}-{a,b,c}'

[merwok]

I also noticed this with such config:

...

[coverage:report]
exclude_lines =
    pragma: no cover

tox -e completion suggests pragma