保留pyproject.toml时pip install -e .无法构建开发版的解决办法

问题背景 #

当项目中存在仅包含black代码格式化配置的pyproject.toml时，执行pip install -e .不会触发传统的Running setup.py develop流程；删除该文件后，才能正常完成开发版安装。需要在保留pyproject.toml的前提下实现开发版构建。

相关配置文件 #

pyproject.toml内容 #

# Source https://github.com/psf/black#configuration-format
[tool.black]
line-length = 100
target-version = ['py38']
exclude = '''

'''

setup.py内容 #

from setuptools import find_namespace_packages
from setuptools import setup

setup(
    name="webservice",
    packages=find_packages(),
    version="0.1.0",
    description="description",
    author="Author",
    license="License",
)

执行日志对比 #

同时存在两个文件时的执行日志 #

(webservice_tool)pk@LAP1:~/webservice_tool$ pip install -e .
Obtaining file:///home/pk/webservice_tool
  Installing build dependencies ... done
  Checking if build backend supports build_editable ... done
  Getting requirements to build editable ... done
  Preparing editable metadata (pyproject.toml) ... done
Building wheels for collected packages: webservice
  Building editable for webservice (pyproject.toml) ... done
  Created wheel for webservice: filename=webservice-0.1.0-0.editable-py3-none-any.whl size=4070 sha256=dcb7c034ba437503d1059fe9370ccafbda144cd19f3e5d92340a63a7da396422
  Stored in directory: /tmp/pip-ephem-wheel-cache-6iqiqbob/wheels/e6/b5/ba/40d8c3d66df94ee2ae46e181034e0c3c47132784db53284d0b
Successfully built webservice
Installing collected packages: webservice
Successfully installed webservice-0.1.0

删除pyproject.toml后的执行日志 #

(webservice_tool) pk@LAP1:~/webservice_tool$ pip install -e .
Obtaining file:///home/pk/webservice_tool
  Preparing metadata (setup.py) ... done
Installing collected packages: webservice
  Attempting uninstall: webservice
    Found existing installation: webservice 0.1.0
    Uninstalling webservice-0.1.0:
      Successfully uninstalled webservice-0.1.0
  Running setup.py develop for webservice
Successfully installed webservice-0.1.0

环境相关包版本 #

packaging                 21.3               pyhd3eb1b0_0  
pip                       22.1.2           py38h06a4308_0  
python                    3.8.13               h12debd9_0  
setuptools                61.2.0           py38h06a4308_0  

项目目录结构 #

|-- data_utils
|   |-- clean_cache.py
|   `-- advanced_utils.py
|-- deployment
|   |-- base_deployment
|   |   |-- auth-proxy.yaml
|   |   |-- kustomization.yaml
|   |   |-- webapi.yaml
|   |   `-- webui.yaml
|   `-- mysql_from_helm
|       |-- mysql-from-helm.yaml
|       `-- mysql-kustomization.yaml
|-- docker-compose.yml
|-- Dockerfile
|-- environment.yml
|-- live_api
|   |-- definitions.json
|   |-- __init__.py
|   `-- live_api.py
|-- params.py
|-- pyproject.toml
|-- setup.py
|-- shared_helpers
|   |-- data_cleaning.py
|   |-- handle_time.py
|   |-- __init__.py
|   |-- plot_timesequence.py
|   |-- read_samples.py
|   `-- save_samples.py
|-- setup.py
|-- util.py
|-- webtool
|   |-- clean_data
|   |   |-- clean_data.py
|   |   `-- __init__.py
|   |-- evaluation
|   |   |-- draw_figures.py
|   |   |-- __init__.py
|   |   `-- webtool_metrics.py
|   |-- __init__.py
|   |-- preprocess
|   |   |-- __init__.py
|   |   `-- preprocess.py
|   |-- ui
|   |   |-- __init__.py
|   |   `-- create_ui.py
|   `-- util
|       |-- data_input.py
|       |-- data_redefinitions.py
|       `-- __init__.py
|-- webtool.egg-info
|   |-- dependency_links.txt
|   |-- entry_points.txt
|   |-- PKG-INFO
|   |-- SOURCES.txt
|   `-- top_level.txt
`-- webtool_tests
    |-- clean_data
    |   `-- test_clean_data.py
    |-- evaluation
    |   `-- test_draw_figures.py
    |-- preprocess
    |   `-- test_preprocess.py
    `-- util
        |-- test_data_input.py
        `-- test_data_redefinitions.py

解决方案 #

问题根源在于：当pyproject.toml存在但未指定构建后端时，pip会默认启用PEP 517/518的隔离构建流程，而非传统的setup.py develop模式。要保留pyproject.toml同时实现开发版安装，只需在pyproject.toml中添加build-system配置，明确指定使用setuptools构建后端：

修改后的pyproject.toml如下：

# Source https://github.com/psf/black#configuration-format
[tool.black]
line-length = 100
target-version = ['py38']
exclude = '''

'''

[build-system]
requires = ["setuptools>=61.0", "wheel"]
build-backend = "setuptools.build_meta"

添加该配置后，再次执行pip install -e .，就会触发与删除pyproject.toml时一致的setup.py develop流程，同时保留black的格式化配置。

备选方案（不推荐） #

如果临时需要绕过隔离构建，可以执行：

pip install -e . --no-build-isolation

但此方法可能引发依赖冲突，仅建议临时测试使用。

内容的提问来源于stack exchange，提问作者PetKie