b4: propagated Python missing ply, gitpython modules

[blitz]

Nixpkgs version

• Unstable (25.05)

Describe the bug

When calling b4 prep --check it calls scripts/spdycheck.py from the Linux source. This script pulls in Python via #!/usr/bin/env python3. This is unfortunately a Python lacking modules to execute the script. Given that this overrides any Python I have in PATH, there is no good solution for the user to make this work.

$ b4 prep --check                                
Checking patches using:
  /home/julian/src/own/linux/scripts/checkpatch.pl -q --terse --no-summary --mailback --showfile
---
...
  ● checkpatch.pl: Traceback (most recent call last):
  ● checkpatch.pl:   File "/home/julian/src/own/linux/scripts/spdxcheck.py", line 6, in <module>
  ● checkpatch.pl:     from ply import lex, yacc
  ● checkpatch.pl: ModuleNotFoundError: No module named 'ply'

Adding ply and gitpython modules to propagatedBuildInputs in the b4 derivation doesn't fix this.

This is unfortunate, because any Python in PATH that has these modules is ignored. So from my perspective, the solution would be to either propagate a Python with the right modules or not propagate a Python at all.

Steps to reproduce

• Git clone this Linux branch: https://github.com/blitz/linux/tree/initrd-erofs
• Execute b4 prep --check

Expected behaviour

b4 prep either adds no Python to PATH of utilities it calls or one with the right modules.

Screenshots

No response

Relevant log output

Additional context

No response

System metadata

❯ nix run nixpkgs#nix-info -- -m

• system: "x86_64-linux"
• host os: Linux 6.13.7, NixOS, 24.11 (Vicuna), 24.11.20250319.b75693f
• multi-user?: yes
• sandbox: yes
• version: nix-env (Lix, like Nix) 2.92.0 System type: x86_64-linux Additional system types: aarch64-linux, i686-linux Features: gc, signed-caches System configuration file: /etc/nix/nix.conf User configuration files: /home/julian/.config/nix/nix.conf:/etc/xdg/nix/nix.conf:/home/julian/.nix-profile/etc/xdg/nix/nix.conf:/nix/profile/etc/xdg/nix/nix.conf:/home/julian/.local/state/nix/profile/etc/xdg/nix/nix.conf:/etc/profiles/per-user/julian/etc/xdg/nix/nix.conf:/nix/var/nix/profiles/default/etc/xdg/nix/nix.conf:/run/current-system/sw/etc/xdg/nix/nix.conf:/nix/store/ys1zqxjyiczkny9bfi1f7i6clm1z39cd-gnome-settings-daemon-47.2/etc/xdg/nix/nix.conf Store directory: /nix/store State directory: /nix/var/nix Data directory: /nix/store/vyfqgaip2hbylhhm1lci1zfvxv6a5g28-lix-2.92.0/share
• channels(root): ""
• nixpkgs: /nix/store/xnws56qm6sg7yc7dbw62c1y24s9jhcpf-source

Notify maintainers

@jb55 @mfrw @alyssais

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