check_pr.py

#!/usr/bin/env python3
"""Pre-push PR check: commit subjects, issue link, Review plan line, screenshots for UI changes.

scripts/check_pr.py BODY_FILE [--base origin/main] [--ui | --no-ui]
Run it before opening a PR. Run scripts/check_pr_body.py too; it checks the template sections.
"""

import argparse
import re
import subprocess
import sys
from pathlib import Path

TYPES = "build|chore|ci|docs|feat|fix|perf|refactor|revert|style|test"
SUBJECT = re.compile(rf"(?:{TYPES})(?:\([a-z0-9][a-z0-9._/-]*\))?!?: \S.*")
FENCE = re.compile(r"^ {0,3}(`{3,}|~{3,})")
CLOSES = re.compile(r" {0,3}Closes #[1-9][0-9]*[ \t]*")
PLAN = re.compile(r"\s{0,3}(?:[-*] )?\**Review plan\**:\**\s*\S", re.I)
IMAGE = re.compile(r"!\[[^\]]*\]\(\s*<?https://[^)\s>]+|<img\b[^>]*\bsrc=[\"']https://", re.I)
UI_PATH = re.compile(
    r"\.(tsx|jsx|vue|svelte|css|scss|html)$|^(apps/[^/]+/(web|src/components|public)|site)/", re.I
)


def check_commits(subjects):
    errors = []
    for subject in subjects:
        if len(subject) > 100:
            errors.append(f"Commit subject is over 100 characters: {subject}")
        elif not SUBJECT.fullmatch(subject) or subject.endswith("."):
            errors.append(
                f"Commit subject is not '<type>(<scope>): <text>' with no final period: {subject}"
            )
    return errors


def prose(body):
    """Body lines outside code fences."""
    fence, lines = "", []
    for line in body.splitlines():
        marker = FENCE.match(line)
        if fence:
            if marker and marker[1][0] == fence[0] and len(marker[1]) >= len(fence):
                fence = ""
        elif marker:
            fence = marker[1]
        else:
            lines.append(line)
    return lines


def check_body(body, ui):
    lines = prose(body)
    first = next((line for line in lines if line.strip()), "")
    errors = []
    if not CLOSES.fullmatch(first):
        errors.append("Start the body with Closes #N for the issue that the PR resolves.")
    if not any(PLAN.match(line) for line in lines):
        errors.append("Add a 'Review plan: <how a reviewer checks this>' line to the body.")
    if ui and not any(IMAGE.search(line) for line in lines):
        errors.append(
            "The diff changes UI files: embed a hosted screenshot (https image) in the body."
        )
    return errors


def git(*args):
    return subprocess.run(
        ["git", *args], check=True, capture_output=True, text=True
    ).stdout.splitlines()


def main():
    parser = argparse.ArgumentParser(description=__doc__.splitlines()[0])
    parser.add_argument("body_file", help="PR body file, or - for stdin")
    parser.add_argument("--base", default="origin/main")
    group = parser.add_mutually_exclusive_group()
    group.add_argument("--ui", action="store_true", help="force the screenshot check")
    group.add_argument("--no-ui", action="store_true", help="skip the screenshot check")
    args = parser.parse_args()
    body = sys.stdin.read() if args.body_file == "-" else Path(args.body_file).read_text()
    try:
        subjects = git("log", "--no-merges", "--format=%s", f"{args.base}..HEAD")
        changed = git("diff", "--name-only", f"{args.base}...HEAD")
    except subprocess.CalledProcessError as error:
        print(error.stderr.strip() or f"git failed for base {args.base}", file=sys.stderr)
        return 2
    ui = args.ui or (not args.no_ui and any(UI_PATH.search(path) for path in changed))
    errors = check_commits(subjects) + check_body(body, ui)
    if errors:
        print("\n".join(errors), file=sys.stderr)
        return 1
    print("PR is ready to open.")
    return 0


if __name__ == "__main__":
    sys.exit(main())