tox.ini syntax error messages

[jayvdb]

These two ini files cause rather unhelpful error backtraces. The first exception has a line number which could be used to provide a useful error message. The second doesnt have a line number (that might be fixable upstream in iniconfig), and the testenv name is hidden in the py3 backtrace("python" in ...ConfigError: python failed..) so that could be made more prominent.

Obviously these are contrived ini files; they are intentionally minimal test cases to show what can happen if a \ is accidentally misplaced. Reading iniconfig source, it looks like similar errors can be triggered with misplaced : , and semantic errors like duplicate or missing section names or item names.

\
[tox]
foo = 1

[testenv]
setenv = \

Backtraces respectively:

Traceback (most recent call last):
  File "/usr/lib/python3.8/site-packages/py/_vendored_packages/iniconfig.py", line 126, in _parseline
    name, value = line.split('=', 1)
ValueError: not enough values to unpack (expected 2, got 1)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.8/site-packages/py/_vendored_packages/iniconfig.py", line 131, in _parseline
    name, value = line.split(":", 1)
ValueError: not enough values to unpack (expected 2, got 1)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/bin/tox", line 8, in <module>
    sys.exit(cmdline())
  File "/usr/lib/python3.8/site-packages/tox/session/__init__.py", line 44, in cmdline
    main(args)
  File "/usr/lib/python3.8/site-packages/tox/session/__init__.py", line 64, in main
    config = load_config(args)
  File "/usr/lib/python3.8/site-packages/tox/session/__init__.py", line 80, in load_config
    config = parseconfig(args)
  File "/usr/lib/python3.8/site-packages/tox/config/__init__.py", line 269, in parseconfig
    ParseIni(config, config_file, content)
  File "/usr/lib/python3.8/site-packages/tox/config/__init__.py", line 1038, in __init__
    self._cfg = py.iniconfig.IniConfig(config.toxinipath, ini_data)
  File "/usr/lib/python3.8/site-packages/py/_vendored_packages/iniconfig.py", line 54, in __init__
    tokens = self._parse(iter(f))
  File "/usr/lib/python3.8/site-packages/py/_vendored_packages/iniconfig.py", line 83, in _parse
    name, data = self._parseline(line, lineno)
  File "/usr/lib/python3.8/site-packages/py/_vendored_packages/iniconfig.py", line 133, in _parseline
    self._raise(lineno, 'unexpected line: %r' % line)
  File "/usr/lib/python3.8/site-packages/py/_vendored_packages/iniconfig.py", line 77, in _raise
    raise ParseError(self.path, lineno, msg)
py._vendored_packages.iniconfig.ParseError: /home/jayvdb/tmp/invalid-tox-ini/tox.ini:1: unexpected line: '\\'

Traceback (most recent call last):
  File "/usr/bin/tox", line 8, in <module>
    sys.exit(cmdline())
  File "/usr/lib/python3.8/site-packages/tox/session/__init__.py", line 44, in cmdline
    main(args)
  File "/usr/lib/python3.8/site-packages/tox/session/__init__.py", line 64, in main
    config = load_config(args)
  File "/usr/lib/python3.8/site-packages/tox/session/__init__.py", line 80, in load_config
    config = parseconfig(args)
  File "/usr/lib/python3.8/site-packages/tox/config/__init__.py", line 269, in parseconfig
    ParseIni(config, config_file, content)
  File "/usr/lib/python3.8/site-packages/tox/config/__init__.py", line 1181, in __init__
    raise tox.exception.ConfigError(
tox.exception.ConfigError: ConfigError: python failed with not enough values to unpack (expected 2, got 1) at Traceback (most recent call last):
  File "/usr/lib/python3.8/site-packages/tox/config/__init__.py", line 1157, in run
    results[name] = cur_self.make_envconfig(name, section, subs, config)
  File "/usr/lib/python3.8/site-packages/tox/config/__init__.py", line 1305, in make_envconfig
    res = meth(env_attr.name, env_attr.default, replace=replace)
  File "/usr/lib/python3.8/site-packages/tox/config/__init__.py", line 1524, in getdict_setenv
    definitions = self._getdict(value, default=default, sep=sep, replace=replace)
  File "/usr/lib/python3.8/site-packages/tox/config/__init__.py", line 1535, in _getdict
    name, rest = line.split("=", 1)
ValueError: not enough values to unpack (expected 2, got 1)

[gaborbernat]

Agreed we should have a more user-friendly error for these.

[jayvdb]

I suspect a non-empty file without a section header resulting in py._vendored_packages.iniconfig.ParseError tox.ini:2: no section header defined is not nicely handled.

[gaborbernat]

Traceback (most recent call last):
  File "/home/bernat/.local/bin/tox4", line 33, in <module>
    sys.exit(load_entry_point('tox', 'console_scripts', 'tox4')())
  File "/home/bernat/git/tox/src/tox/run.py", line 18, in run
    result = main(sys.argv[1:] if args is None else args)
  File "/home/bernat/git/tox/src/tox/run.py", line 37, in main
    state = setup_state(args)
  File "/home/bernat/git/tox/src/tox/run.py", line 52, in setup_state
    options = get_options(*args)
  File "/home/bernat/git/tox/src/tox/config/cli/parse.py", line 36, in get_options
    guess_verbosity, log_handler, source = _get_base(args)
  File "/home/bernat/git/tox/src/tox/config/cli/parse.py", line 51, in _get_base
    source = discover_source(parsed.config_file, parsed.root_dir)
  File "/home/bernat/git/tox/src/tox/config/source/discover.py", line 26, in discover_source
    src = _locate_source()
  File "/home/bernat/git/tox/src/tox/config/source/discover.py", line 40, in _locate_source
    return src_type(candidate)
  File "/home/bernat/git/tox/src/tox/config/source/ini.py", line 32, in __init__
    self._parser.read_string(content, str(path))
  File "/usr/lib/python3.10/configparser.py", line 724, in read_string
    self.read_file(sfile, source)
  File "/usr/lib/python3.10/configparser.py", line 719, in read_file
    self._read(f, source)
  File "/usr/lib/python3.10/configparser.py", line 1086, in _read
    raise MissingSectionHeaderError(fpname, lineno, line)
configparser.MissingSectionHeaderError: File contains no section headers.
file: '/tmp/magic/tox.ini', line: 1
'\\\n'

❯ tox4
py: internal error
Traceback (most recent call last):
  File "/home/bernat/git/tox/src/tox/session/cmd/run/single.py", line 45, in _evaluate
    tox_env.setup()
  File "/home/bernat/git/tox/src/tox/tox_env/api.py", line 226, in setup
    self._setup_env()
  File "/home/bernat/git/tox/src/tox/tox_env/python/runner.py", line 90, in _setup_env
    super()._setup_env()
  File "/home/bernat/git/tox/src/tox/tox_env/python/api.py", line 158, in _setup_env
    self.ensure_python_env()
  File "/home/bernat/git/tox/src/tox/tox_env/python/api.py", line 162, in ensure_python_env
    conf = self.python_cache()
  File "/home/bernat/git/tox/src/tox/tox_env/python/virtual_env/api.py", line 78, in python_cache
    base = super().python_cache()
  File "/home/bernat/git/tox/src/tox/tox_env/python/api.py", line 196, in python_cache
    "version_info": list(self.base_python.version_info),
  File "/home/bernat/git/tox/src/tox/tox_env/python/api.py", line 205, in base_python
    self._base_python = self._get_python(base_pythons)
  File "/home/bernat/git/tox/src/tox/tox_env/python/virtual_env/api.py", line 135, in _get_python
    interpreter = self.creator.interpreter
  File "/home/bernat/git/tox/src/tox/tox_env/python/virtual_env/api.py", line 127, in creator
    return self.session.creator
  File "/home/bernat/git/tox/src/tox/tox_env/python/virtual_env/api.py", line 107, in session
    env = self.virtualenv_env_vars()
  File "/home/bernat/git/tox/src/tox/tox_env/python/virtual_env/api.py", line 112, in virtualenv_env_vars
    env = self.environment_variables.copy()
  File "/home/bernat/git/tox/src/tox/tox_env/python/virtual_env/api.py", line 167, in environment_variables
    environment_variables = super().environment_variables
  File "/home/bernat/git/tox/src/tox/tox_env/runner.py", line 196, in environment_variables
    environment_variables = super().environment_variables
  File "/home/bernat/git/tox/src/tox/tox_env/api.py", line 301, in environment_variables
    set_env: SetEnv = self.conf["set_env"]
  File "/home/bernat/git/tox/src/tox/config/sets.py", line 112, in __getitem__
    return self.load(item)
  File "/home/bernat/git/tox/src/tox/config/sets.py", line 123, in load
    return config_definition.__call__(self._conf, self.loaders, ConfigLoadArgs(chain, self.name, self.env_name))
  File "/home/bernat/git/tox/src/tox/config/of_type.py", line 102, in __call__
    value = loader.load(key, self.of_type, self.factory, conf, args)
  File "/home/bernat/git/tox/src/tox/config/loader/api.py", line 127, in load
    converted = self.to(prepared, of_type, factory)
  File "/home/bernat/git/tox/src/tox/config/loader/convert.py", line 53, in to
    return factory(raw)
  File "/home/bernat/git/tox/src/tox/config/sets.py", line 225, in set_env_factory
    return SetEnv(raw, self.name, self.env_name, root)
  File "/home/bernat/git/tox/src/tox/config/set_env.py", line 29, in __init__
    key, value = self._extract_key_value(line)
  File "/home/bernat/git/tox/src/tox/config/set_env.py", line 67, in _extract_key_value
    raise ValueError(f"invalid line {line!r} in set_env")
ValueError: invalid line '\\' in set_env

Seems fixed in version 4.