bug: custom `install_command` is only respected from `tox.ini`, not `pyproject.toml`

## Issue



The `install_command` [configuration option](https://tox.wiki/en/stable/config.html#install_command) is not respected when specified in `pyproject.toml` format, but works correctly when specified in `tox.ini` format. When using TOML configuration, tox falls back to the default `python -I -m pip install` command instead of using the specified custom install command.

### Expected behavior: 
Both TOML and INI formats should respect the `install_command` setting and use the custom installation command.
### Observed behavior: 
Only the INI format uses the custom `install_command`, while the TOML format ignores it and uses the default pip installation method.
## Environment
<details>

- OS: macOS 
- tox version: 4.28.4
- python version: 3.11-3.13

```console
~/Repositories/tox-toml-bug main*
❯ uv pip list
Package            Version
------------------ --------
cachetools         6.1.0
certifi            2025.8.3
chardet            5.2.0
charset-normalizer 3.4.2
colorama           0.4.6
distlib            0.4.0
filelock           3.18.0
idna               3.10
packaging          25.0
platformdirs       4.3.8
pluggy             1.6.0
pyproject-api      1.9.1
requests           2.32.4
tox                4.28.4
urllib3            2.5.0
virtualenv         20.33.0
```

</details>

## Output of running tox



<details open>
<summary>Output of <code>tox -rvv</code> (with only <code>pyproject.toml</code>) </summary>

```console
~/Repositories/tox-toml-bug main*
❯ uv run tox -rvv
.pkg: 123 W remove tox env folder /Users/owen/Repositories/tox-toml-bug/.tox/.pkg [tox/tox_env/api.py:359]
py: 126 I find interpreter for spec PythonSpec(path=/Users/owen/Repositories/tox-toml-bug/.venv/bin/python) [virtualenv/discovery/
builtin.py:78]
py: 126 D filesystem is not case-sensitive [virtualenv/info.py:27]
py: 127 D got python info of /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin/python3.13 from /Users/owen/
Library/Application Support/virtualenv/py_info/2/0ec5037196bd9d7c4aff542ff5a961565317dd5aa27c5a0981e7c537da664c13.json [virtualenv
/app_data/via_disk_folder.py:132]
py: 127 I proposed PythonInfo(spec=CPython3.13.1.final.0-64, system=/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch6
4-none/bin/python3.13, exe=/Users/owen/Repositories/tox-toml-bug/.venv/bin/python, platform=darwin, version='3.13.1 (main, Jan 14 
2025, 23:31:50) [Clang 19.1.6 ]', encoding_fs_io=utf-8-utf-8) [virtualenv/discovery/builtin.py:85]
py: 127 D accepted PythonInfo(spec=CPython3.13.1.final.0-64, system=/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch6
4-none/bin/python3.13, exe=/Users/owen/Repositories/tox-toml-bug/.venv/bin/python, platform=darwin, version='3.13.1 (main, Jan 14 
2025, 23:31:50) [Clang 19.1.6 ]', encoding_fs_io=utf-8-utf-8) [virtualenv/discovery/builtin.py:87]
py: 128 D symlink on filesystem does work [virtualenv/info.py:50]
py: 145 I create virtual environment via CPython3Posix(dest=/Users/owen/Repositories/tox-toml-bug/.tox/py, clear=False, no_vcs_ign
ore=False, global=False) [virtualenv/run/session.py:52]
py: 145 D create folder /Users/owen/Repositories/tox-toml-bug/.tox/py/bin [virtualenv/util/path/_sync.py:14]
py: 145 D create folder /Users/owen/Repositories/tox-toml-bug/.tox/py/lib/python3.13/site-packages [virtualenv/util/path/_sync.py:
14]
py: 145 D write /Users/owen/Repositories/tox-toml-bug/.tox/py/pyvenv.cfg [virtualenv/create/pyenv_cfg.py:35]
py: 145 D       home = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin [virtualenv/create/pyenv_cfg.py:40
]
py: 145 D       implementation = CPython [virtualenv/create/pyenv_cfg.py:40]
py: 145 D       version_info = 3.13.1.final.0 [virtualenv/create/pyenv_cfg.py:40]
py: 145 D       virtualenv = 20.33.0 [virtualenv/create/pyenv_cfg.py:40]
py: 145 D       include-system-site-packages = false [virtualenv/create/pyenv_cfg.py:40]
py: 145 D       base-prefix = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none [virtualenv/create/pyenv_cfg.py
:40]
py: 145 D       base-exec-prefix = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none [virtualenv/create/pyenv_c
fg.py:40]
py: 145 D       base-executable = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin/python3.13 [virtualenv/
create/pyenv_cfg.py:40]
py: 145 D symlink /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin/python3.13 to /Users/owen/Repositories/
tox-toml-bug/.tox/py/bin/python [virtualenv/util/path/_sync.py:34]
py: 146 D create virtualenv import hook file /Users/owen/Repositories/tox-toml-bug/.tox/py/lib/python3.13/site-packages/_virtualen
v.pth [virtualenv/create/via_global_ref/api.py:98]
py: 146 D create /Users/owen/Repositories/tox-toml-bug/.tox/py/lib/python3.13/site-packages/_virtualenv.py [virtualenv/create/via_
global_ref/api.py:101]
py: 146 D ============================== target debug ============================== [virtualenv/run/session.py:54]
py: 146 D debug via /Users/owen/Repositories/tox-toml-bug/.tox/py/bin/python /Users/owen/Repositories/tox-toml-bug/.venv/lib/pytho
n3.13/site-packages/virtualenv/create/debug.py [virtualenv/create/creator.py:215]
py: 146 D {
  "sys": {
    "executable": "/Users/owen/Repositories/tox-toml-bug/.tox/py/bin/python",
    "_base_executable": "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin/python3.13",
    "prefix": "/Users/owen/Repositories/tox-toml-bug/.tox/py",
    "base_prefix": "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none",
    "real_prefix": null,
    "exec_prefix": "/Users/owen/Repositories/tox-toml-bug/.tox/py",
    "base_exec_prefix": "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none",
    "path": [
      "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python313.zip",
      "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13",
      "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13/lib-dynload",
      "/Users/owen/Repositories/tox-toml-bug/.tox/py/lib/python3.13/site-packages"
    ],
    "meta_path": [
      "<class '_virtualenv._Finder'>",
      "<class '_frozen_importlib.BuiltinImporter'>",
      "<class '_frozen_importlib.FrozenImporter'>",
      "<class '_frozen_importlib_external.PathFinder'>"
    ],
    "fs_encoding": "utf-8",
    "io_encoding": "utf-8"
  },
  "version": "3.13.1 (main, Jan 14 2025, 23:31:50) [Clang 19.1.6 ]",
  "makefile_filename": "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13/config-3.13-darwin/Mak
efile",
  "os": "<module 'os' (frozen)>",
  "site": "<module 'site' (frozen)>",
  "datetime": "<module 'datetime' from '/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13/dateti
me.py'>",
  "math": "<module 'math' (built-in)>",
  "json": "<module 'json' from '/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13/json/__init__.
py'>"
} [virtualenv/run/session.py:55]
py: 172 I add seed packages via FromAppData(download=False, pip=bundle, via=copy, app_data_dir=/Users/owen/Library/Application Sup
port/virtualenv) [virtualenv/run/session.py:59]
py: 173 D install pip from wheel /Users/owen/Repositories/tox-toml-bug/.venv/lib/python3.13/site-packages/virtualenv/seed/wheels/e
mbed/pip-25.1.1-py3-none-any.whl via CopyPipInstall [virtualenv/seed/embed/via_app_data/via_app_data.py:51]
py: 174 D copy directory /Users/owen/Library/Application Support/virtualenv/wheel/3.13/image/1/CopyPipInstall/pip-25.1.1-py3-none-
any/pip-25.1.1.dist-info to /Users/owen/Repositories/tox-toml-bug/.tox/py/lib/python3.13/site-packages/pip-25.1.1.dist-info [virtu
alenv/util/path/_sync.py:42]
py: 176 D copy directory /Users/owen/Library/Application Support/virtualenv/wheel/3.13/image/1/CopyPipInstall/pip-25.1.1-py3-none-
any/pip to /Users/owen/Repositories/tox-toml-bug/.tox/py/lib/python3.13/site-packages/pip [virtualenv/util/path/_sync.py:42]
py: 281 D copy /Users/owen/Library/Application Support/virtualenv/wheel/3.13/image/1/CopyPipInstall/pip-25.1.1-py3-none-any/pip-25
.1.1.virtualenv to /Users/owen/Repositories/tox-toml-bug/.tox/py/lib/python3.13/site-packages/pip-25.1.1.virtualenv [virtualenv/ut
il/path/_sync.py:42]
py: 282 D generated console scripts pip3.13 pip pip3 pip-3.13 [virtualenv/seed/embed/via_app_data/pip_install/base.py:45]
py: 283 I add activators for Bash, CShell, Fish, Nushell, PowerShell, Python [virtualenv/run/session.py:65]
py: 284 D write /Users/owen/Repositories/tox-toml-bug/.tox/py/pyvenv.cfg [virtualenv/create/pyenv_cfg.py:35]
py: 284 D       home = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin [virtualenv/create/pyenv_cfg.py:40
]
py: 284 D       implementation = CPython [virtualenv/create/pyenv_cfg.py:40]
py: 284 D       version_info = 3.13.1.final.0 [virtualenv/create/pyenv_cfg.py:40]
py: 284 D       virtualenv = 20.33.0 [virtualenv/create/pyenv_cfg.py:40]
py: 284 D       include-system-site-packages = false [virtualenv/create/pyenv_cfg.py:40]
py: 285 D       base-prefix = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none [virtualenv/create/pyenv_cfg.py
:40]
py: 285 D       base-exec-prefix = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none [virtualenv/create/pyenv_c
fg.py:40]
py: 285 D       base-executable = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin/python3.13 [virtualenv/
create/pyenv_cfg.py:40]
.pkg: 287 I find interpreter for spec PythonSpec(path=/Users/owen/Repositories/tox-toml-bug/.venv/bin/python) [virtualenv/discover
y/builtin.py:78]
.pkg: 287 I proposed PythonInfo(spec=CPython3.13.1.final.0-64, system=/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarc
h64-none/bin/python3.13, exe=/Users/owen/Repositories/tox-toml-bug/.venv/bin/python, platform=darwin, version='3.13.1 (main, Jan 1
4 2025, 23:31:50) [Clang 19.1.6 ]', encoding_fs_io=utf-8-utf-8) [virtualenv/discovery/builtin.py:85]
.pkg: 287 D accepted PythonInfo(spec=CPython3.13.1.final.0-64, system=/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarc
h64-none/bin/python3.13, exe=/Users/owen/Repositories/tox-toml-bug/.venv/bin/python, platform=darwin, version='3.13.1 (main, Jan 1
4 2025, 23:31:50) [Clang 19.1.6 ]', encoding_fs_io=utf-8-utf-8) [virtualenv/discovery/builtin.py:87]
.pkg: 287 I create virtual environment via CPython3Posix(dest=/Users/owen/Repositories/tox-toml-bug/.tox/.pkg, clear=False, no_vcs
_ignore=False, global=False) [virtualenv/run/session.py:52]
.pkg: 287 D create folder /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/bin [virtualenv/util/path/_sync.py:14]
.pkg: 287 D create folder /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/lib/python3.13/site-packages [virtualenv/util/path/_sync
.py:14]
.pkg: 288 D write /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/pyvenv.cfg [virtualenv/create/pyenv_cfg.py:35]
.pkg: 288 D     home = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin [virtualenv/create/pyenv_cfg.py:40
]
.pkg: 288 D     implementation = CPython [virtualenv/create/pyenv_cfg.py:40]
.pkg: 288 D     version_info = 3.13.1.final.0 [virtualenv/create/pyenv_cfg.py:40]
.pkg: 288 D     virtualenv = 20.33.0 [virtualenv/create/pyenv_cfg.py:40]
.pkg: 288 D     include-system-site-packages = false [virtualenv/create/pyenv_cfg.py:40]
.pkg: 288 D     base-prefix = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none [virtualenv/create/pyenv_cfg.py
:40]
.pkg: 288 D     base-exec-prefix = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none [virtualenv/create/pyenv_c
fg.py:40]
.pkg: 288 D     base-executable = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin/python3.13 [virtualenv/
create/pyenv_cfg.py:40]
.pkg: 288 D symlink /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin/python3.13 to /Users/owen/Repositorie
s/tox-toml-bug/.tox/.pkg/bin/python [virtualenv/util/path/_sync.py:34]
.pkg: 288 D create virtualenv import hook file /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/lib/python3.13/site-packages/_virtu
alenv.pth [virtualenv/create/via_global_ref/api.py:98]
.pkg: 288 D create /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/lib/python3.13/site-packages/_virtualenv.py [virtualenv/create/
via_global_ref/api.py:101]
.pkg: 289 D ============================== target debug ============================== [virtualenv/run/session.py:54]
.pkg: 289 D debug via /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/bin/python /Users/owen/Repositories/tox-toml-bug/.venv/lib/p
ython3.13/site-packages/virtualenv/create/debug.py [virtualenv/create/creator.py:215]
.pkg: 289 D {
  "sys": {
    "executable": "/Users/owen/Repositories/tox-toml-bug/.tox/.pkg/bin/python",
    "_base_executable": "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin/python3.13",
    "prefix": "/Users/owen/Repositories/tox-toml-bug/.tox/.pkg",
    "base_prefix": "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none",
    "real_prefix": null,
    "exec_prefix": "/Users/owen/Repositories/tox-toml-bug/.tox/.pkg",
    "base_exec_prefix": "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none",
    "path": [
      "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python313.zip",
      "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13",
      "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13/lib-dynload",
      "/Users/owen/Repositories/tox-toml-bug/.tox/.pkg/lib/python3.13/site-packages"
    ],
    "meta_path": [
      "<class '_virtualenv._Finder'>",
      "<class '_frozen_importlib.BuiltinImporter'>",
      "<class '_frozen_importlib.FrozenImporter'>",
      "<class '_frozen_importlib_external.PathFinder'>"
    ],
    "fs_encoding": "utf-8",
    "io_encoding": "utf-8"
  },
  "version": "3.13.1 (main, Jan 14 2025, 23:31:50) [Clang 19.1.6 ]",
  "makefile_filename": "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13/config-3.13-darwin/Mak
efile",
  "os": "<module 'os' (frozen)>",
  "site": "<module 'site' (frozen)>",
  "datetime": "<module 'datetime' from '/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13/dateti
me.py'>",
  "math": "<module 'math' (built-in)>",
  "json": "<module 'json' from '/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13/json/__init__.
py'>"
} [virtualenv/run/session.py:55]
.pkg: 314 I add seed packages via FromAppData(download=False, pip=bundle, via=copy, app_data_dir=/Users/owen/Library/Application S
upport/virtualenv) [virtualenv/run/session.py:59]
.pkg: 315 D install pip from wheel /Users/owen/Repositories/tox-toml-bug/.venv/lib/python3.13/site-packages/virtualenv/seed/wheels
/embed/pip-25.1.1-py3-none-any.whl via CopyPipInstall [virtualenv/seed/embed/via_app_data/via_app_data.py:51]
.pkg: 315 D copy directory /Users/owen/Library/Application Support/virtualenv/wheel/3.13/image/1/CopyPipInstall/pip-25.1.1-py3-non
e-any/pip-25.1.1.dist-info to /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/lib/python3.13/site-packages/pip-25.1.1.dist-info [v
irtualenv/util/path/_sync.py:42]
.pkg: 317 D copy directory /Users/owen/Library/Application Support/virtualenv/wheel/3.13/image/1/CopyPipInstall/pip-25.1.1-py3-non
e-any/pip to /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/lib/python3.13/site-packages/pip [virtualenv/util/path/_sync.py:42]
.pkg: 382 D copy /Users/owen/Library/Application Support/virtualenv/wheel/3.13/image/1/CopyPipInstall/pip-25.1.1-py3-none-any/pip-
25.1.1.virtualenv to /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/lib/python3.13/site-packages/pip-25.1.1.virtualenv [virtualen
v/util/path/_sync.py:42]
.pkg: 383 D generated console scripts pip pip3 pip3.13 pip-3.13 [virtualenv/seed/embed/via_app_data/pip_install/base.py:45]
.pkg: 383 I add activators for Bash, CShell, Fish, Nushell, PowerShell, Python [virtualenv/run/session.py:65]
.pkg: 384 D write /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/pyvenv.cfg [virtualenv/create/pyenv_cfg.py:35]
.pkg: 385 D     home = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin [virtualenv/create/pyenv_cfg.py:40
]
.pkg: 385 D     implementation = CPython [virtualenv/create/pyenv_cfg.py:40]
.pkg: 385 D     version_info = 3.13.1.final.0 [virtualenv/create/pyenv_cfg.py:40]
.pkg: 385 D     virtualenv = 20.33.0 [virtualenv/create/pyenv_cfg.py:40]
.pkg: 385 D     include-system-site-packages = false [virtualenv/create/pyenv_cfg.py:40]
.pkg: 385 D     base-prefix = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none [virtualenv/create/pyenv_cfg.py
:40]
.pkg: 385 D     base-exec-prefix = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none [virtualenv/create/pyenv_c
fg.py:40]
.pkg: 385 D     base-executable = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin/python3.13 [virtualenv/
create/pyenv_cfg.py:40]
.pkg: 385 W install_requires> python -I -m pip install 'setuptools>=40.8.0' [tox/tox_env/api.py:461]
Collecting setuptools>=40.8.0
  Using cached setuptools-80.9.0-py3-none-any.whl.metadata (6.6 kB)
Using cached setuptools-80.9.0-py3-none-any.whl (1.2 MB)
Installing collected packages: setuptools
Successfully installed setuptools-80.9.0
.pkg: 1637 I exit 0 (1.25 seconds) /Users/owen/Repositories/tox-toml-bug> python -I -m pip install 'setuptools>=40.8.0' pid=55433 
[tox/execute/api.py:294]
.pkg: 1637 W _optional_hooks> python /Users/owen/Repositories/tox-toml-bug/.venv/lib/python3.13/site-packages/pyproject_api/_backe
nd.py True setuptools.build_meta __legacy__ [tox/tox_env/api.py:461]
Backend: run command _optional_hooks with args {}
Backend: Wrote response {'return': {'get_requires_for_build_sdist': True, 'prepare_metadata_for_build_wheel': True, 'get_requires_
for_build_wheel': True, 'build_editable': True, 'get_requires_for_build_editable': True, 'prepare_metadata_for_build_editable': Tr
ue}} to /var/folders/m7/px9njwzj5b57shppcx0dx4_40000gn/T/pep517__optional_hooks-i7m09104.json
.pkg: 1730 I exit None (0.09 seconds) /Users/owen/Repositories/tox-toml-bug> python /Users/owen/Repositories/tox-toml-bug/.venv/li
b/python3.13/site-packages/pyproject_api/_backend.py True setuptools.build_meta __legacy__ pid=55434 [tox/execute/api.py:294]
.pkg: 1858 W get_requires_for_build_sdist> python /Users/owen/Repositories/tox-toml-bug/.venv/lib/python3.13/site-packages/pyproje
ct_api/_backend.py True setuptools.build_meta __legacy__ [tox/tox_env/api.py:461]
Backend: run command get_requires_for_build_sdist with args {'config_settings': None}
running egg_info
writing tox_toml_bug.egg-info/PKG-INFO
writing dependency_links to tox_toml_bug.egg-info/dependency_links.txt
writing requirements to tox_toml_bug.egg-info/requires.txt
writing top-level names to tox_toml_bug.egg-info/top_level.txt
reading manifest file 'tox_toml_bug.egg-info/SOURCES.txt'
writing manifest file 'tox_toml_bug.egg-info/SOURCES.txt'
Backend: Wrote response {'return': []} to /var/folders/m7/px9njwzj5b57shppcx0dx4_40000gn/T/pep517_get_requires_for_build_sdist-0xa
ebs1h.json
.pkg: 1973 I exit None (0.11 seconds) /Users/owen/Repositories/tox-toml-bug> python /Users/owen/Repositories/tox-toml-bug/.venv/li
b/python3.13/site-packages/pyproject_api/_backend.py True setuptools.build_meta __legacy__ pid=55435 [tox/execute/api.py:294]
.pkg: 2091 W build_sdist> python /Users/owen/Repositories/tox-toml-bug/.venv/lib/python3.13/site-packages/pyproject_api/_backend.p
y True setuptools.build_meta __legacy__ [tox/tox_env/api.py:461]
Backend: run command build_sdist with args {'sdist_directory': '/Users/owen/Repositories/tox-toml-bug/.tox/.pkg/dist', 'config_set
tings': None}
running sdist
running egg_info
writing tox_toml_bug.egg-info/PKG-INFO
writing dependency_links to tox_toml_bug.egg-info/dependency_links.txt
writing requirements to tox_toml_bug.egg-info/requires.txt
writing top-level names to tox_toml_bug.egg-info/top_level.txt
reading manifest file 'tox_toml_bug.egg-info/SOURCES.txt'
writing manifest file 'tox_toml_bug.egg-info/SOURCES.txt'
running check
creating tox_toml_bug-0.1.0
creating tox_toml_bug-0.1.0/tox_toml_bug.egg-info
copying files to tox_toml_bug-0.1.0...
copying README.md -> tox_toml_bug-0.1.0
copying main.py -> tox_toml_bug-0.1.0
copying pyproject.toml -> tox_toml_bug-0.1.0
copying tox_toml_bug.egg-info/PKG-INFO -> tox_toml_bug-0.1.0/tox_toml_bug.egg-info
copying tox_toml_bug.egg-info/SOURCES.txt -> tox_toml_bug-0.1.0/tox_toml_bug.egg-info
copying tox_toml_bug.egg-info/dependency_links.txt -> tox_toml_bug-0.1.0/tox_toml_bug.egg-info
copying tox_toml_bug.egg-info/requires.txt -> tox_toml_bug-0.1.0/tox_toml_bug.egg-info
copying tox_toml_bug.egg-info/top_level.txt -> tox_toml_bug-0.1.0/tox_toml_bug.egg-info
copying tox_toml_bug.egg-info/SOURCES.txt -> tox_toml_bug-0.1.0/tox_toml_bug.egg-info
Writing tox_toml_bug-0.1.0/setup.cfg
Creating tar archive
removing 'tox_toml_bug-0.1.0' (and everything under it)
Backend: Wrote response {'return': 'tox_toml_bug-0.1.0.tar.gz'} to /var/folders/m7/px9njwzj5b57shppcx0dx4_40000gn/T/pep517_build_s
dist-ccq2lxb3.json
.pkg: 2214 I exit None (0.12 seconds) /Users/owen/Repositories/tox-toml-bug> python /Users/owen/Repositories/tox-toml-bug/.venv/li
b/python3.13/site-packages/pyproject_api/_backend.py True setuptools.build_meta __legacy__ pid=55436 [tox/execute/api.py:294]
.pkg: 2331 D package .tmp/package/1/tox_toml_bug-0.1.0.tar.gz links to .pkg/dist/tox_toml_bug-0.1.0.tar.gz (/Users/owen/Repositori
es/tox-toml-bug/.tox) [tox/util/file_view.py:39]
py: 2331 W install_package_deps> python -I -m pip install 'requests>=2.32.4' 'tox>=4.28.4' [tox/tox_env/api.py:461]
Collecting requests>=2.32.4
  Using cached requests-2.32.4-py3-none-any.whl.metadata (4.9 kB)
Collecting tox>=4.28.4
  Using cached tox-4.28.4-py3-none-any.whl.metadata (3.6 kB)
Collecting charset_normalizer<4,>=2 (from requests>=2.32.4)
  Using cached charset_normalizer-3.4.2-cp313-cp313-macosx_10_13_universal2.whl.metadata (35 kB)
Collecting idna<4,>=2.5 (from requests>=2.32.4)
  Using cached idna-3.10-py3-none-any.whl.metadata (10 kB)
Collecting urllib3<3,>=1.21.1 (from requests>=2.32.4)
  Using cached urllib3-2.5.0-py3-none-any.whl.metadata (6.5 kB)
Collecting certifi>=2017.4.17 (from requests>=2.32.4)
  Using cached certifi-2025.8.3-py3-none-any.whl.metadata (2.4 kB)
Collecting cachetools>=6.1 (from tox>=4.28.4)
  Using cached cachetools-6.1.0-py3-none-any.whl.metadata (5.4 kB)
Collecting chardet>=5.2 (from tox>=4.28.4)
  Using cached chardet-5.2.0-py3-none-any.whl.metadata (3.4 kB)
Collecting colorama>=0.4.6 (from tox>=4.28.4)
  Using cached colorama-0.4.6-py2.py3-none-any.whl.metadata (17 kB)
Collecting filelock>=3.18 (from tox>=4.28.4)
  Using cached filelock-3.18.0-py3-none-any.whl.metadata (2.9 kB)
Collecting packaging>=25 (from tox>=4.28.4)
  Using cached packaging-25.0-py3-none-any.whl.metadata (3.3 kB)
Collecting platformdirs>=4.3.8 (from tox>=4.28.4)
  Using cached platformdirs-4.3.8-py3-none-any.whl.metadata (12 kB)
Collecting pluggy>=1.6 (from tox>=4.28.4)
  Using cached pluggy-1.6.0-py3-none-any.whl.metadata (4.8 kB)
Collecting pyproject-api>=1.9.1 (from tox>=4.28.4)
  Using cached pyproject_api-1.9.1-py3-none-any.whl.metadata (2.7 kB)
Collecting virtualenv>=20.31.2 (from tox>=4.28.4)
  Using cached virtualenv-20.33.0-py3-none-any.whl.metadata (4.5 kB)
Collecting distlib<1,>=0.3.7 (from virtualenv>=20.31.2->tox>=4.28.4)
  Using cached distlib-0.4.0-py2.py3-none-any.whl.metadata (5.2 kB)
Using cached requests-2.32.4-py3-none-any.whl (64 kB)
Using cached charset_normalizer-3.4.2-cp313-cp313-macosx_10_13_universal2.whl (199 kB)
Using cached idna-3.10-py3-none-any.whl (70 kB)
Using cached urllib3-2.5.0-py3-none-any.whl (129 kB)
Using cached tox-4.28.4-py3-none-any.whl (174 kB)
Using cached cachetools-6.1.0-py3-none-any.whl (11 kB)
Using cached certifi-2025.8.3-py3-none-any.whl (161 kB)
Using cached chardet-5.2.0-py3-none-any.whl (199 kB)
Using cached colorama-0.4.6-py2.py3-none-any.whl (25 kB)
Using cached filelock-3.18.0-py3-none-any.whl (16 kB)
Using cached packaging-25.0-py3-none-any.whl (66 kB)
Using cached platformdirs-4.3.8-py3-none-any.whl (18 kB)
Using cached pluggy-1.6.0-py3-none-any.whl (20 kB)
Using cached pyproject_api-1.9.1-py3-none-any.whl (13 kB)
Using cached virtualenv-20.33.0-py3-none-any.whl (6.1 MB)
Using cached distlib-0.4.0-py2.py3-none-any.whl (469 kB)
Installing collected packages: distlib, urllib3, pluggy, platformdirs, packaging, idna, filelock, colorama, charset_normalizer, ch
ardet, certifi, cachetools, virtualenv, requests, pyproject-api, tox
Successfully installed cachetools-6.1.0 certifi-2025.8.3 chardet-5.2.0 charset_normalizer-3.4.2 colorama-0.4.6 distlib-0.4.0 filel
ock-3.18.0 idna-3.10 packaging-25.0 platformdirs-4.3.8 pluggy-1.6.0 pyproject-api-1.9.1 requests-2.32.4 tox-4.28.4 urllib3-2.5.0 v
irtualenv-20.33.0
py: 3813 I exit 0 (1.48 seconds) /Users/owen/Repositories/tox-toml-bug> python -I -m pip install 'requests>=2.32.4' 'tox>=4.28.4' 
pid=55437 [tox/execute/api.py:294]
py: 3813 W install_package> python -I -m pip install --force-reinstall --no-deps /Users/owen/Repositories/tox-toml-bug/.tox/.tmp/p

~/Repositories/tox-toml-bug main*
❯ uv run tox -rvv
py: 97 W remove tox env folder /Users/owen/Repositories/tox-toml-bug/.tox/py [tox/tox_env/api.py:359]
.pkg: 193 W remove tox env folder /Users/owen/Repositories/tox-toml-bug/.tox/.pkg [tox/tox_env/api.py:359]
py: 286 I find interpreter for spec PythonSpec(path=/Users/owen/Repositories/tox-toml-bug/.venv/bin/python) [virtualenv/discovery/
builtin.py:78]
py: 286 D filesystem is not case-sensitive [virtualenv/info.py:27]
py: 287 D got python info of /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin/python3.13 from /Users/owen/
Library/Application Support/virtualenv/py_info/2/0ec5037196bd9d7c4aff542ff5a961565317dd5aa27c5a0981e7c537da664c13.json [virtualenv
/app_data/via_disk_folder.py:132]
py: 287 I proposed PythonInfo(spec=CPython3.13.1.final.0-64, system=/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch6
4-none/bin/python3.13, exe=/Users/owen/Repositories/tox-toml-bug/.venv/bin/python, platform=darwin, version='3.13.1 (main, Jan 14 
2025, 23:31:50) [Clang 19.1.6 ]', encoding_fs_io=utf-8-utf-8) [virtualenv/discovery/builtin.py:85]
py: 287 D accepted PythonInfo(spec=CPython3.13.1.final.0-64, system=/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch6
4-none/bin/python3.13, exe=/Users/owen/Repositories/tox-toml-bug/.venv/bin/python, platform=darwin, version='3.13.1 (main, Jan 14 
2025, 23:31:50) [Clang 19.1.6 ]', encoding_fs_io=utf-8-utf-8) [virtualenv/discovery/builtin.py:87]
py: 288 D symlink on filesystem does work [virtualenv/info.py:50]
py: 300 I create virtual environment via CPython3Posix(dest=/Users/owen/Repositories/tox-toml-bug/.tox/py, clear=False, no_vcs_ign
ore=False, global=False) [virtualenv/run/session.py:52]
py: 300 D create folder /Users/owen/Repositories/tox-toml-bug/.tox/py/bin [virtualenv/util/path/_sync.py:14]
py: 300 D create folder /Users/owen/Repositories/tox-toml-bug/.tox/py/lib/python3.13/site-packages [virtualenv/util/path/_sync.py:
14]
py: 300 D write /Users/owen/Repositories/tox-toml-bug/.tox/py/pyvenv.cfg [virtualenv/create/pyenv_cfg.py:35]
py: 301 D       home = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin [virtualenv/create/pyenv_cfg.py:40
]
py: 301 D       implementation = CPython [virtualenv/create/pyenv_cfg.py:40]
py: 301 D       version_info = 3.13.1.final.0 [virtualenv/create/pyenv_cfg.py:40]
py: 301 D       virtualenv = 20.33.0 [virtualenv/create/pyenv_cfg.py:40]
py: 301 D       include-system-site-packages = false [virtualenv/create/pyenv_cfg.py:40]
py: 301 D       base-prefix = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none [virtualenv/create/pyenv_cfg.py
:40]
py: 301 D       base-exec-prefix = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none [virtualenv/create/pyenv_c
fg.py:40]
py: 301 D       base-executable = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin/python3.13 [virtualenv/
create/pyenv_cfg.py:40]
py: 301 D symlink /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin/python3.13 to /Users/owen/Repositories/
tox-toml-bug/.tox/py/bin/python [virtualenv/util/path/_sync.py:34]
py: 301 D create virtualenv import hook file /Users/owen/Repositories/tox-toml-bug/.tox/py/lib/python3.13/site-packages/_virtualen
v.pth [virtualenv/create/via_global_ref/api.py:98]
py: 301 D create /Users/owen/Repositories/tox-toml-bug/.tox/py/lib/python3.13/site-packages/_virtualenv.py [virtualenv/create/via_
global_ref/api.py:101]
py: 302 D ============================== target debug ============================== [virtualenv/run/session.py:54]
py: 302 D debug via /Users/owen/Repositories/tox-toml-bug/.tox/py/bin/python /Users/owen/Repositories/tox-toml-bug/.venv/lib/pytho
n3.13/site-packages/virtualenv/create/debug.py [virtualenv/create/creator.py:215]
py: 302 D {
  "sys": {
    "executable": "/Users/owen/Repositories/tox-toml-bug/.tox/py/bin/python",
    "_base_executable": "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin/python3.13",
    "prefix": "/Users/owen/Repositories/tox-toml-bug/.tox/py",
    "base_prefix": "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none",
    "real_prefix": null,
    "exec_prefix": "/Users/owen/Repositories/tox-toml-bug/.tox/py",
    "base_exec_prefix": "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none",
    "path": [
      "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python313.zip",
      "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13",
      "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13/lib-dynload",
      "/Users/owen/Repositories/tox-toml-bug/.tox/py/lib/python3.13/site-packages"
    ],
    "meta_path": [
      "<class '_virtualenv._Finder'>",
      "<class '_frozen_importlib.BuiltinImporter'>",
      "<class '_frozen_importlib.FrozenImporter'>",
      "<class '_frozen_importlib_external.PathFinder'>"
    ],
    "fs_encoding": "utf-8",
    "io_encoding": "utf-8"
  },
  "version": "3.13.1 (main, Jan 14 2025, 23:31:50) [Clang 19.1.6 ]",
  "makefile_filename": "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13/config-3.13-darwin/Mak
efile",
  "os": "<module 'os' (frozen)>",
  "site": "<module 'site' (frozen)>",
  "datetime": "<module 'datetime' from '/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13/dateti
me.py'>",
  "math": "<module 'math' (built-in)>",
  "json": "<module 'json' from '/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13/json/__init__.
py'>"
} [virtualenv/run/session.py:55]
py: 328 I add seed packages via FromAppData(download=False, pip=bundle, via=copy, app_data_dir=/Users/owen/Library/Application Sup
port/virtualenv) [virtualenv/run/session.py:59]
py: 329 D install pip from wheel /Users/owen/Repositories/tox-toml-bug/.venv/lib/python3.13/site-packages/virtualenv/seed/wheels/e
mbed/pip-25.1.1-py3-none-any.whl via CopyPipInstall [virtualenv/seed/embed/via_app_data/via_app_data.py:51]
py: 330 D copy directory /Users/owen/Library/Application Support/virtualenv/wheel/3.13/image/1/CopyPipInstall/pip-25.1.1-py3-none-
any/pip-25.1.1.dist-info to /Users/owen/Repositories/tox-toml-bug/.tox/py/lib/python3.13/site-packages/pip-25.1.1.dist-info [virtu
alenv/util/path/_sync.py:42]
py: 332 D copy directory /Users/owen/Library/Application Support/virtualenv/wheel/3.13/image/1/CopyPipInstall/pip-25.1.1-py3-none-
any/pip to /Users/owen/Repositories/tox-toml-bug/.tox/py/lib/python3.13/site-packages/pip [virtualenv/util/path/_sync.py:42]
py: 401 D copy /Users/owen/Library/Application Support/virtualenv/wheel/3.13/image/1/CopyPipInstall/pip-25.1.1-py3-none-any/pip-25
.1.1.virtualenv to /Users/owen/Repositories/tox-toml-bug/.tox/py/lib/python3.13/site-packages/pip-25.1.1.virtualenv [virtualenv/ut
il/path/_sync.py:42]
py: 402 D generated console scripts pip3.13 pip3 pip pip-3.13 [virtualenv/seed/embed/via_app_data/pip_install/base.py:45]
py: 402 I add activators for Bash, CShell, Fish, Nushell, PowerShell, Python [virtualenv/run/session.py:65]
py: 404 D write /Users/owen/Repositories/tox-toml-bug/.tox/py/pyvenv.cfg [virtualenv/create/pyenv_cfg.py:35]
py: 404 D       home = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin [virtualenv/create/pyenv_cfg.py:40
]
py: 404 D       implementation = CPython [virtualenv/create/pyenv_cfg.py:40]
py: 404 D       version_info = 3.13.1.final.0 [virtualenv/create/pyenv_cfg.py:40]
py: 404 D       virtualenv = 20.33.0 [virtualenv/create/pyenv_cfg.py:40]
py: 404 D       include-system-site-packages = false [virtualenv/create/pyenv_cfg.py:40]
py: 404 D       base-prefix = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none [virtualenv/create/pyenv_cfg.py
:40]
py: 404 D       base-exec-prefix = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none [virtualenv/create/pyenv_c
fg.py:40]
py: 404 D       base-executable = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin/python3.13 [virtualenv/
create/pyenv_cfg.py:40]
.pkg: 406 I find interpreter for spec PythonSpec(path=/Users/owen/Repositories/tox-toml-bug/.venv/bin/python) [virtualenv/discover
y/builtin.py:78]
.pkg: 407 I proposed PythonInfo(spec=CPython3.13.1.final.0-64, system=/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarc
h64-none/bin/python3.13, exe=/Users/owen/Repositories/tox-toml-bug/.venv/bin/python, platform=darwin, version='3.13.1 (main, Jan 1
4 2025, 23:31:50) [Clang 19.1.6 ]', encoding_fs_io=utf-8-utf-8) [virtualenv/discovery/builtin.py:85]
.pkg: 407 D accepted PythonInfo(spec=CPython3.13.1.final.0-64, system=/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarc
h64-none/bin/python3.13, exe=/Users/owen/Repositories/tox-toml-bug/.venv/bin/python, platform=darwin, version='3.13.1 (main, Jan 1
4 2025, 23:31:50) [Clang 19.1.6 ]', encoding_fs_io=utf-8-utf-8) [virtualenv/discovery/builtin.py:87]
.pkg: 407 I create virtual environment via CPython3Posix(dest=/Users/owen/Repositories/tox-toml-bug/.tox/.pkg, clear=False, no_vcs
_ignore=False, global=False) [virtualenv/run/session.py:52]
.pkg: 407 D create folder /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/bin [virtualenv/util/path/_sync.py:14]
.pkg: 407 D create folder /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/lib/python3.13/site-packages [virtualenv/util/path/_sync
.py:14]
.pkg: 408 D write /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/pyvenv.cfg [virtualenv/create/pyenv_cfg.py:35]
.pkg: 408 D     home = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin [virtualenv/create/pyenv_cfg.py:40
]
.pkg: 408 D     implementation = CPython [virtualenv/create/pyenv_cfg.py:40]
.pkg: 408 D     version_info = 3.13.1.final.0 [virtualenv/create/pyenv_cfg.py:40]
.pkg: 408 D     virtualenv = 20.33.0 [virtualenv/create/pyenv_cfg.py:40]
.pkg: 408 D     include-system-site-packages = false [virtualenv/create/pyenv_cfg.py:40]
.pkg: 408 D     base-prefix = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none [virtualenv/create/pyenv_cfg.py
:40]
.pkg: 408 D     base-exec-prefix = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none [virtualenv/create/pyenv_c
fg.py:40]
.pkg: 408 D     base-executable = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin/python3.13 [virtualenv/
create/pyenv_cfg.py:40]
.pkg: 408 D symlink /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin/python3.13 to /Users/owen/Repositorie
s/tox-toml-bug/.tox/.pkg/bin/python [virtualenv/util/path/_sync.py:34]
.pkg: 408 D create virtualenv import hook file /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/lib/python3.13/site-packages/_virtu
alenv.pth [virtualenv/create/via_global_ref/api.py:98]
.pkg: 408 D create /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/lib/python3.13/site-packages/_virtualenv.py [virtualenv/create/
via_global_ref/api.py:101]
.pkg: 408 D ============================== target debug ============================== [virtualenv/run/session.py:54]
.pkg: 408 D debug via /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/bin/python /Users/owen/Repositories/tox-toml-bug/.venv/lib/p
ython3.13/site-packages/virtualenv/create/debug.py [virtualenv/create/creator.py:215]
.pkg: 408 D {
  "sys": {
    "executable": "/Users/owen/Repositories/tox-toml-bug/.tox/.pkg/bin/python",
    "_base_executable": "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin/python3.13",
    "prefix": "/Users/owen/Repositories/tox-toml-bug/.tox/.pkg",
    "base_prefix": "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none",
    "real_prefix": null,
    "exec_prefix": "/Users/owen/Repositories/tox-toml-bug/.tox/.pkg",
    "base_exec_prefix": "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none",
    "path": [
      "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python313.zip",
      "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13",
      "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13/lib-dynload",
      "/Users/owen/Repositories/tox-toml-bug/.tox/.pkg/lib/python3.13/site-packages"
    ],
    "meta_path": [
      "<class '_virtualenv._Finder'>",
      "<class '_frozen_importlib.BuiltinImporter'>",
      "<class '_frozen_importlib.FrozenImporter'>",
      "<class '_frozen_importlib_external.PathFinder'>"
    ],
    "fs_encoding": "utf-8",
    "io_encoding": "utf-8"
  },
  "version": "3.13.1 (main, Jan 14 2025, 23:31:50) [Clang 19.1.6 ]",
  "makefile_filename": "/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13/config-3.13-darwin/Mak
efile",
  "os": "<module 'os' (frozen)>",
  "site": "<module 'site' (frozen)>",
  "datetime": "<module 'datetime' from '/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13/dateti
me.py'>",
  "math": "<module 'math' (built-in)>",
  "json": "<module 'json' from '/Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/lib/python3.13/json/__init__.
py'>"
} [virtualenv/run/session.py:55]
.pkg: 434 I add seed packages via FromAppData(download=False, pip=bundle, via=copy, app_data_dir=/Users/owen/Library/Application S
upport/virtualenv) [virtualenv/run/session.py:59]
.pkg: 434 D install pip from wheel /Users/owen/Repositories/tox-toml-bug/.venv/lib/python3.13/site-packages/virtualenv/seed/wheels
/embed/pip-25.1.1-py3-none-any.whl via CopyPipInstall [virtualenv/seed/embed/via_app_data/via_app_data.py:51]
.pkg: 435 D copy directory /Users/owen/Library/Application Support/virtualenv/wheel/3.13/image/1/CopyPipInstall/pip-25.1.1-py3-non
e-any/pip-25.1.1.dist-info to /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/lib/python3.13/site-packages/pip-25.1.1.dist-info [v
irtualenv/util/path/_sync.py:42]
.pkg: 436 D copy directory /Users/owen/Library/Application Support/virtualenv/wheel/3.13/image/1/CopyPipInstall/pip-25.1.1-py3-non
e-any/pip to /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/lib/python3.13/site-packages/pip [virtualenv/util/path/_sync.py:42]
.pkg: 507 D copy /Users/owen/Library/Application Support/virtualenv/wheel/3.13/image/1/CopyPipInstall/pip-25.1.1-py3-none-any/pip-
25.1.1.virtualenv to /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/lib/python3.13/site-packages/pip-25.1.1.virtualenv [virtualen
v/util/path/_sync.py:42]
.pkg: 508 D generated console scripts pip3 pip-3.13 pip3.13 pip [virtualenv/seed/embed/via_app_data/pip_install/base.py:45]
.pkg: 508 I add activators for Bash, CShell, Fish, Nushell, PowerShell, Python [virtualenv/run/session.py:65]
.pkg: 510 D write /Users/owen/Repositories/tox-toml-bug/.tox/.pkg/pyvenv.cfg [virtualenv/create/pyenv_cfg.py:35]
.pkg: 510 D     home = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin [virtualenv/create/pyenv_cfg.py:40
]
.pkg: 510 D     implementation = CPython [virtualenv/create/pyenv_cfg.py:40]
.pkg: 510 D     version_info = 3.13.1.final.0 [virtualenv/create/pyenv_cfg.py:40]
.pkg: 510 D     virtualenv = 20.33.0 [virtualenv/create/pyenv_cfg.py:40]
.pkg: 510 D     include-system-site-packages = false [virtualenv/create/pyenv_cfg.py:40]
.pkg: 510 D     base-prefix = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none [virtualenv/create/pyenv_cfg.py
:40]
.pkg: 510 D     base-exec-prefix = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none [virtualenv/create/pyenv_c
fg.py:40]
.pkg: 510 D     base-executable = /Users/owen/.local/share/uv/python/cpython-3.13.1-macos-aarch64-none/bin/python3.13 [virtualenv/
create/pyenv_cfg.py:40]
.pkg: 511 W install_requires> python -I -m pip install 'setuptools>=40.8.0' [tox/tox_env/api.py:461]
Collecting setuptools>=40.8.0
  Using cached setuptools-80.9.0-py3-none-any.whl.metadata (6.6 kB)
Using cached setuptools-80.9.0-py3-none-any.whl (1.2 MB)
Installing collected packages: setuptools
Successfully installed setuptools-80.9.0
.pkg: 1606 I exit 0 (1.10 seconds) /Users/owen/Repositories/tox-toml-bug> python -I -m pip install 'setuptools>=40.8.0' pid=55480 
[tox/execute/api.py:294]
.pkg: 1607 W _optional_hooks> python /Users/owen/Repositories/tox-toml-bug/.venv/lib/python3.13/site-packages/pyproject_api/_backe
nd.py True setuptools.build_meta __legacy__ [tox/tox_env/api.py:461]
Backend: run command _optional_hooks with args {}
Backend: Wrote response {'return': {'get_requires_for_build_sdist': True, 'prepare_metadata_for_build_wheel': True, 'get_requires_
for_build_wheel': True, 'build_editable': True, 'get_requires_for_build_editable': True, 'prepare_metadata_for_build_editable': Tr
ue}} to /var/folders/m7/px9njwzj5b57shppcx0dx4_40000gn/T/pep517__optional_hooks-dbyk26cg.json
.pkg: 1684 I exit None (0.08 seconds) /Users/owen/Repositories/tox-toml-bug> python /Users/owen/Repositories/tox-toml-bug/.venv/li
b/python3.13/site-packages/pyproject_api/_backend.py True setuptools.build_meta __legacy__ pid=55481 [tox/execute/api.py:294]
.pkg: 1799 W get_requires_for_build_sdist> python /Users/owen/Repositories/tox-toml-bug/.venv/lib/python3.13/site-packages/pyproje
ct_api/_backend.py True setuptools.build_meta __legacy__ [tox/tox_env/api.py:461]
Backend: run command get_requires_for_build_sdist with args {'config_settings': None}
running egg_info
writing tox_toml_bug.egg-info/PKG-INFO
writing dependency_links to tox_toml_bug.egg-info/dependency_links.txt
writing requirements to tox_toml_bug.egg-info/requires.txt
writing top-level names to tox_toml_bug.egg-info/top_level.txt
reading manifest file 'tox_toml_bug.egg-info/SOURCES.txt'
writing manifest file 'tox_toml_bug.egg-info/SOURCES.txt'
Backend: Wrote response {'return': []} to /var/folders/m7/px9njwzj5b57shppcx0dx4_40000gn/T/pep517_get_requires_for_build_sdist-4vy
u2ixe.json
.pkg: 1917 I exit None (0.12 seconds) /Users/owen/Repositories/tox-toml-bug> python /Users/owen/Repositories/tox-toml-bug/.venv/li
b/python3.13/site-packages/pyproject_api/_backend.py True setuptools.build_meta __legacy__ pid=55482 [tox/execute/api.py:294]
.pkg: 2033 W build_sdist> python /Users/owen/Repositories/tox-toml-bug/.venv/lib/python3.13/site-packages/pyproject_api/_backend.p
y True setuptools.build_meta __legacy__ [tox/tox_env/api.py:461]
Backend: run command build_sdist with args {'sdist_directory': '/Users/owen/Repositories/tox-toml-bug/.tox/.pkg/dist', 'config_set
tings': None}
running sdist
running egg_info
writing tox_toml_bug.egg-info/PKG-INFO
writing dependency_links to tox_toml_bug.egg-info/dependency_links.txt
writing requirements to tox_toml_bug.egg-info/requires.txt
writing top-level names to tox_toml_bug.egg-info/top_level.txt
reading manifest file 'tox_toml_bug.egg-info/SOURCES.txt'
writing manifest file 'tox_toml_bug.egg-info/SOURCES.txt'
running check
creating tox_toml_bug-0.1.0
creating tox_toml_bug-0.1.0/tox_toml_bug.egg-info
copying files to tox_toml_bug-0.1.0...
copying README.md -> tox_toml_bug-0.1.0
copying main.py -> tox_toml_bug-0.1.0
copying pyproject.toml -> tox_toml_bug-0.1.0
copying tox_toml_bug.egg-info/PKG-INFO -> tox_toml_bug-0.1.0/tox_toml_bug.egg-info
copying tox_toml_bug.egg-info/SOURCES.txt -> tox_toml_bug-0.1.0/tox_toml_bug.egg-info
copying tox_toml_bug.egg-info/dependency_links.txt -> tox_toml_bug-0.1.0/tox_toml_bug.egg-info
copying tox_toml_bug.egg-info/requires.txt -> tox_toml_bug-0.1.0/tox_toml_bug.egg-info
copying tox_toml_bug.egg-info/top_level.txt -> tox_toml_bug-0.1.0/tox_toml_bug.egg-info
copying tox_toml_bug.egg-info/SOURCES.txt -> tox_toml_bug-0.1.0/tox_toml_bug.egg-info
Writing tox_toml_bug-0.1.0/setup.cfg
Creating tar archive
removing 'tox_toml_bug-0.1.0' (and everything under it)
Backend: Wrote response {'return': 'tox_toml_bug-0.1.0.tar.gz'} to /var/folders/m7/px9njwzj5b57shppcx0dx4_40000gn/T/pep517_build_s
dist-q7g6a96b.json
.pkg: 2154 I exit None (0.12 seconds) /Users/owen/Repositories/tox-toml-bug> python /Users/owen/Repositories/tox-toml-bug/.venv/li
b/python3.13/site-packages/pyproject_api/_backend.py True setuptools.build_meta __legacy__ pid=55483 [tox/execute/api.py:294]
.pkg: 2272 D package .tmp/package/2/tox_toml_bug-0.1.0.tar.gz links to .pkg/dist/tox_toml_bug-0.1.0.tar.gz (/Users/owen/Repositori
es/tox-toml-bug/.tox) [tox/util/file_view.py:39]
py: 2273 W install_package_deps> python -I -m pip install 'requests>=2.32.4' 'tox>=4.28.4' [tox/tox_env/api.py:461]
Collecting requests>=2.32.4
  Using cached requests-2.32.4-py3-none-any.whl.metadata (4.9 kB)
Collecting tox>=4.28.4
  Using cached tox-4.28.4-py3-none-any.whl.metadata (3.6 kB)
Collecting charset_normalizer<4,>=2 (from requests>=2.32.4)
  Using cached charset_normalizer-3.4.2-cp313-cp313-macosx_10_13_universal2.whl.metadata (35 kB)
Collecting idna<4,>=2.5 (from requests>=2.32.4)
  Using cached idna-3.10-py3-none-any.whl.metadata (10 kB)
Collecting urllib3<3,>=1.21.1 (from requests>=2.32.4)
  Using cached urllib3-2.5.0-py3-none-any.whl.metadata (6.5 kB)
Collecting certifi>=2017.4.17 (from requests>=2.32.4)
  Using cached certifi-2025.8.3-py3-none-any.whl.metadata (2.4 kB)
Collecting cachetools>=6.1 (from tox>=4.28.4)
  Using cached cachetools-6.1.0-py3-none-any.whl.metadata (5.4 kB)
Collecting chardet>=5.2 (from tox>=4.28.4)
  Using cached chardet-5.2.0-py3-none-any.whl.metadata (3.4 kB)
Collecting colorama>=0.4.6 (from tox>=4.28.4)
  Using cached colorama-0.4.6-py2.py3-none-any.whl.metadata (17 kB)
Collecting filelock>=3.18 (from tox>=4.28.4)
  Using cached filelock-3.18.0-py3-none-any.whl.metadata (2.9 kB)
Collecting packaging>=25 (from tox>=4.28.4)
  Using cached packaging-25.0-py3-none-any.whl.metadata (3.3 kB)
Collecting platformdirs>=4.3.8 (from tox>=4.28.4)
  Using cached platformdirs-4.3.8-py3-none-any.whl.metadata (12 kB)
Collecting pluggy>=1.6 (from tox>=4.28.4)
  Using cached pluggy-1.6.0-py3-none-any.whl.metadata (4.8 kB)
Collecting pyproject-api>=1.9.1 (from tox>=4.28.4)
  Using cached pyproject_api-1.9.1-py3-none-any.whl.metadata (2.7 kB)
Collecting virtualenv>=20.31.2 (from tox>=4.28.4)
  Using cached virtualenv-20.33.0-py3-none-any.whl.metadata (4.5 kB)
Collecting distlib<1,>=0.3.7 (from virtualenv>=20.31.2->tox>=4.28.4)
  Using cached distlib-0.4.0-py2.py3-none-any.whl.metadata (5.2 kB)
Using cached requests-2.32.4-py3-none-any.whl (64 kB)
Using cached charset_normalizer-3.4.2-cp313-cp313-macosx_10_13_universal2.whl (199 kB)
Using cached idna-3.10-py3-none-any.whl (70 kB)
Using cached urllib3-2.5.0-py3-none-any.whl (129 kB)
Using cached tox-4.28.4-py3-none-any.whl (174 kB)
Using cached cachetools-6.1.0-py3-none-any.whl (11 kB)
Using cached certifi-2025.8.3-py3-none-any.whl (161 kB)
Using cached chardet-5.2.0-py3-none-any.whl (199 kB)
Using cached colorama-0.4.6-py2.py3-none-any.whl (25 kB)
Using cached filelock-3.18.0-py3-none-any.whl (16 kB)
Using cached packaging-25.0-py3-none-any.whl (66 kB)
Using cached platformdirs-4.3.8-py3-none-any.whl (18 kB)
Using cached pluggy-1.6.0-py3-none-any.whl (20 kB)
Using cached pyproject_api-1.9.1-py3-none-any.whl (13 kB)
Using cached virtualenv-20.33.0-py3-none-any.whl (6.1 MB)
Using cached distlib-0.4.0-py2.py3-none-any.whl (469 kB)
Installing collected packages: distlib, urllib3, pluggy, platformdirs, packaging, idna, filelock, colorama, charset_normalizer, ch
ardet, certifi, cachetools, virtualenv, requests, pyproject-api, tox
Successfully installed cachetools-6.1.0 certifi-2025.8.3 chardet-5.2.0 charset_normalizer-3.4.2 colorama-0.4.6 distlib-0.4.0 filel
ock-3.18.0 idna-3.10 packaging-25.0 platformdirs-4.3.8 pluggy-1.6.0 pyproject-api-1.9.1 requests-2.32.4 tox-4.28.4 urllib3-2.5.0 v
irtualenv-20.33.0
py: 3724 I exit 0 (1.45 seconds) /Users/owen/Repositories/tox-toml-bug> python -I -m pip install 'requests>=2.32.4' 'tox>=4.28.4' 
pid=55484 [tox/execute/api.py:294]
py: 3724 W install_package> python -I -m pip install --force-reinstall --no-deps /Users/owen/Repositories/tox-toml-bug/.tox/.tmp/p
ackage/2/tox_toml_bug-0.1.0.tar.gz [tox/tox_env/api.py:461]
Processing ./.tox/.tmp/package/2/tox_toml_bug-0.1.0.tar.gz
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
  Preparing metadata (pyproject.toml) ... done
Building wheels for collected packages: tox-toml-bug
  Building wheel for tox-toml-bug (pyproject.toml) ... done
  Created wheel for tox-toml-bug: filename=tox_toml_bug-0.1.0-py3-none-any.whl size=1292 sha256=9bd782ec7047448914c2c423d32cd60cab
102b9774f28ea24736f29011b89c87
  Stored in directory: /Users/owen/Library/Caches/pip/wheels/a3/dd/e8/2a4c3d6aa9ff820fca7bc2e55f41538d9eb0fc9d5eb5880720
Successfully built tox-toml-bug
Installing collected packages: tox-toml-bug
Successfully installed tox-toml-bug-0.1.0
py: 4901 I exit 0 (1.18 seconds) /Users/owen/Repositories/tox-toml-bug> python -I -m pip install --force-reinstall --no-deps /User
s/owen/Repositories/tox-toml-bug/.tox/.tmp/package/2/tox_toml_bug-0.1.0.tar.gz pid=55485 [tox/execute/api.py:294]
.pkg: 4901 D delete package /Users/owen/Repositories/tox-toml-bug/.tox/.tmp/package/2/tox_toml_bug-0.1.0.tar.gz [tox/tox_env/pytho
n/virtual_env/package/pyproject.py:224]
  py: OK (4.80 seconds)
  congratulations :) (4.84 seconds)

```

</details>

## Minimal example


`pyproject.toml`:

```toml
[project]
name = "tox-toml-bug"
version = "0.1.0"
description = "Add your description here"
readme = "README.md"
requires-python = ">=3.13"
dependencies = ["requests>=2.32.4", "tox>=4.28.4"]

[tool.tox]
env_list = ["test"]


[tool.tox.env_run_base]
deps = ["requests"]
allowlist_externals = ["uv"]
install_command = "uv pip install {opts} {packages}"
commands = [["python", "-c", "import requests; print('success')"]]
```

`tox.ini`:

```ini
[tox]
env_list = test

[testenv]
allowlist_externals = uv
deps = requests
install_command = uv pip install {opts} {packages}
commands = python -c "import requests; print('success')"
```

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Uh oh!

bug: custom `install_command` is only respected from `tox.ini`, not `pyproject.toml` #3574

Issue

Expected behavior:

Observed behavior:

Environment

Output of running tox

Minimal example

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Uh oh!

bug: custom install_command is only respected from tox.ini, not pyproject.toml #3574

Description

Issue

Expected behavior:

Observed behavior:

Environment

Output of running tox

Minimal example

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions

bug: custom `install_command` is only respected from `tox.ini`, not `pyproject.toml` #3574