#!/usr/bin/env python3

"""

scripts/unstage_cosmetic.py

Unstage (and revert) any currently-staged file whose only diff is the

`POT-Creation-Date` header line. Ported out of the nightly workflow's

inline bash/awk step so the manual version-bump script can produce the

same minimal, noise-free diffs (item 3) -- previously only the workflow

did this, so a human running update_python_version.py and committing

with `git commit -am` would bake pure-timestamp churn into history,

which then became a spurious baseline for the *next* nightly diff too.

Usage:

python scripts/unstage_cosmetic.py

Must be run with a git repo that already has changes staged (e.g. after

`git add --all`).

"""

from __future__ import annotations

import subprocess

import sys

def run(cmd: list) -> subprocess.CompletedProcess:

return subprocess.run(cmd, capture_output=True, text=True, check=True)

def staged_files() -> list:

result = run(["git", "diff", "--staged", "--name-only"])

return [line for line in result.stdout.splitlines() if line]

def has_only_cosmetic_diff(path: str) -> bool:

"""True if every changed (+/-) content line in the staged diff for

`path` is a POT-Creation-Date line (i.e. nothing else changed)."""

result = subprocess.run(

["git", "diff", "--staged", "-U0", "--", path],

capture_output=True,

text=True,

)

changed_lines = [

line

for line in result.stdout.splitlines()

if line.startswith(("+", "-")) and not line.startswith(("+++", "---"))

]

if not changed_lines:

return True

return all("POT-Creation-Date" in line for line in changed_lines)

def main() -> None:

files = staged_files()

if not files:

print("No staged files.")

return

unstaged = []

for path in files:

if has_only_cosmetic_diff(path):

run(["git", "restore", "--staged", path])

run(["git", "restore", path])

unstaged.append(path)

if unstaged:

print(f"Unstaged {len(unstaged)} file(s) with only POT-Creation-Date changes:")

for path in unstaged:

print(f" - {path}")

else:

print("No cosmetic-only files to unstage.")

if __name__ == "__main__":

main()