Fix , being used as value parser for env var configs

Signed-off-by: Bernát Gábor <bgabor8@bloomberg.net>

.pre-commit-config.yaml

@@ -19,7 +19,7 @@ repos:
       - id: pyproject-fmt
         additional_dependencies: ["tox>=4.10"]
   - repo: https://github.com/pre-commit/mirrors-prettier
-    rev: "v3.0.2"
+    rev: "v3.0.3"
     hooks:
       - id: prettier
         args: ["--print-width=120", "--prose-wrap=always"]
@@ -29,7 +29,7 @@ repos:
       - id: blacken-docs
         additional_dependencies: [black==23.7]
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: "v0.0.286"
+    rev: "v0.0.287"
     hooks:
       - id: ruff
         args: [--fix, --exit-non-zero-on-fix]

docs/changelog/3112.bugfix.rst

@@ -0,0 +1,2 @@
+Allow passing in multiple overrides using the ``;`` character and fix ``,`` being used as splitting values -
+by :user:`gaborbernat`.

docs/config.rst

@@ -1025,12 +1025,51 @@ For example, given this config:
 
 You could enable ``ignore_errors`` by running::
 
-    tox --override testenv.ignore_errors=True
+.. code-block:: bash
+
+   tox --override testenv.ignore_errors=True
 
 You could add additional dependencies by running::
 
-    tox --override testenv.deps+=pytest-xdist,pytest-cov
+.. code-block:: bash
+
+   tox --override testenv.deps+=pytest-xdist,pytest-cov
 
 You could set additional environment variables by running::
 
-    tox --override testenv.setenv+=baz=quux
+.. code-block:: bash
+
+   tox --override testenv.setenv+=baz=quux
+
+Set CLI flags via environment variables
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+All CLI flags can be set via environment variables too, the naming convention here is ``TOX_<option>``. E.g.
+``TOX_WORKDIR`` sets the ``--workdir`` flag, or ``TOX_OVERRIDE`` sets the ``--override`` flag. For flags accepting more
+than one arguments (such as override) use the ``;`` character to separate these values:
+
+.. code-block:: bash
+
+   # set FOO and bar as passed environment variable
+   $ env 'TOX_OVERRIDE=testenv.pass_env=FOO,BAR' tox c -k pass_env -e py
+   [testenv:py]
+   pass_env =
+     BAR
+     FOO
+     <default pass_envs>
+
+   # append FOO and bar as passed environment variable to the list already defined in
+   # the tox configuration
+   $ env 'TOX_OVERRIDE=testenv.pass_env+=FOO,BAR' tox c -k pass_env -e py
+   [testenv:py]
+   pass_env =
+     BAR
+     FOO
+     <pass_envs defined in configuration>
+     <default pass_envs>
+
+   # set httpx and deps to and 3.12 as base_python
+   $ env 'TOX_OVERRIDE=testenv.deps=httpx;testenv.base_python=3.12' .tox/dev/bin/tox c \
+         -k deps base_python -e py
+   [testenv:py]
+   deps = httpx
+   base_python = 3.12

src/tox/config/cli/env_var.py

@@ -3,7 +3,7 @@
 
 import logging
 import os
-from typing import Any
+from typing import Any, List
 
 from tox.config.loader.str_convert import StrConvert
 
@@ -22,8 +22,13 @@ def get_env_var(key: str, of_type: type[Any]) -> tuple[Any, str] | None:
     for environ_key in (f"TOX_{key_upper}", f"TOX{key_upper}"):
         if environ_key in os.environ:
             value = os.environ[environ_key]
+            origin = getattr(of_type, "__origin__", of_type.__class__)
             try:
-                result = CONVERT.to(raw=value, of_type=of_type, factory=None)
+                if origin in (list, List):
+                    entry_type = of_type.__args__[0]
+                    result = [CONVERT.to(raw=v, of_type=entry_type, factory=None) for v in value.split(";")]
+                else:
+                    result = CONVERT.to(raw=value, of_type=of_type, factory=None)
             except Exception as exception:  # noqa: BLE001
                 logging.warning(
                     "env var %s=%r cannot be transformed to %r because %r",

src/tox/config/main.py

@@ -140,7 +140,7 @@ def get_section_config(  # noqa: PLR0913
             if for_env is not None:
                 conf_set.loaders.extend(self.memory_seed_loaders.get(for_env, []))
             for loader in self._src.get_loaders(section, base, self._overrides, conf_set):
-                conf_set.loaders.append(loader)  # noqa: PERF402
+                conf_set.loaders.append(loader)
             if loaders is not None:
                 conf_set.loaders.extend(loaders)
             return conf_set

src/tox/tox_env/python/pip/req/file.py

@@ -320,7 +320,7 @@ def _merge_option_line(  # noqa: C901, PLR0912, PLR0915
                 base_opt.features_enabled = []
             for feature in opt.features_enabled:
                 if feature not in base_opt.features_enabled:
-                    base_opt.features_enabled.append(feature)  # noqa: PERF401
+                    base_opt.features_enabled.append(feature)
             base_opt.features_enabled.sort()
         if opt.index_url:
             if getattr(base_opt, "index_url", []):