carbon-lang/proposals/scripts/update_proposal_list.py

#!/usr/bin/env python3

"""Updates the list of proposals in proposals/README.md."""

__copyright__ = """
Part of the Carbon Language project, under the Apache License v2.0 with LLVM
Exceptions. See /LICENSE for license information.
SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
"""

import os
import re
import sys

if __name__ == "__main__":
    # Read the proposal dir relative to this script.
    proposal_dir = os.path.realpath(
        os.path.join(os.path.dirname(sys.argv[0]), "../../proposals/")
    )
    print(proposal_dir)

    # Identify proposal titles in the file list.
    proposals = [
        "<!-- This list is updated by src/scripts/update_proposal_list.py. "
        "-->",
        "",
    ]
    error = False
    for file in sorted(os.listdir(proposal_dir)):
        file_match = re.match(r"^p([0-9]{4})\.md$", file)
        if not file_match:
            continue
        with open(os.path.join(proposal_dir, file)) as f:
            content = f.read()
        title = content.split("\n")[0]
        title_match = re.match(r"^# (.*)$", title)
        if not title_match:
            print("ERROR: %s doesn't have a title on the first line." % file)
            error = True
        proposals.append(
            "-   [%s - %s](%s)" % (file_match[1], title_match[1], file)
        )
        decision_file = "p%s_decision.md" % file_match[1]
        if os.path.exists(os.path.join(proposal_dir, decision_file)):
            proposals.append("    -   [Decision](%s)" % decision_file)
    # We print batched errors for usability, but still need to exit with
    # failure.
    if error:
        sys.exit(1)

    # Replace the README content if needed.
    readme_path = os.path.join(proposal_dir, "README.md")
    with open(readme_path) as f:
        old_content = f.read()
    proposals_re = re.compile(
        r"(.*<!-- proposals -->)(?:.*)(<!-- endproposals -->)",
        re.DOTALL | re.MULTILINE,
    )
    if not proposals_re.match(old_content):
        print(
            "ERROR: proposals/README.md is missing the <!-- proposals --> ... "
            "<!-- endproposals --> marker."
        )
        sys.exit(1)
    new_content = proposals_re.sub(
        r"\1\n%s\n\n\2" % "\n".join(proposals), old_content
    )
    if old_content != new_content:
        print("Updating proposals/README.md")
        with open(readme_path, "w") as f:
            f.write(new_content)