ask_for_import() resets build backend to default

[floxay]

• I have searched the issue tracker and believe that this is not a duplicate.

Make sure you run commands with -v flag before pasting the output.

Steps to reproduce

• Have a requirements.txt or other config file recognized by find_importable_files() in the project:

  pdm/src/pdm/cli/utils.py

  Line 617 in c1c2bf8

  for filename in ("Pipfile", "pyproject.toml", "requirements.in", "requirements.txt", "setup.py", "setup.cfg"):

• Run pdm init
• Tell PDM this project is installable
• Select a build backend (preferably not the default one; setuptools)
• [build backend is now set to setuptools in pyproject.toml]
• Fill out name, email etc. to finish project initialization
• Choose to import from requirements.txt when Found following files from other formats that you may import appears
• Build backend is now back to default

---

I believe this happens because ask_for_import() calls Command.do_import() which just simply replaces it:

pdm/src/pdm/cli/commands/import_cmd.py

Line 86 in c1c2bf8

pyproject["build-system"] = DEFAULT_BACKEND.build_system()

Actual behavior

After initializing and importing PDM will reset the build backend to the default.

Expected behavior

PDM should not reset the build backend, especially if it was specified in the same "session", like in the example above using init.

Environment Information

PDM version:
  2.10.1
Python Interpreter:
  C:\Users\x\Documents\GitHub\test-proj\.venv\Scripts\python.exe (3.11)
Project Root:
  C:/Users/x/Documents/GitHub/test-proj
Local Packages:

{
  "implementation_name": "cpython",
  "implementation_version": "3.11.6",
  "os_name": "nt",
  "platform_machine": "AMD64",
  "platform_release": "10",
  "platform_system": "Windows",
  "platform_version": "10.0.22621",
  "python_full_version": "3.11.6",
  "platform_python_implementation": "CPython",
  "python_version": "3.11",
  "sys_platform": "win32"
}