A Python script that generates a pull request body

pull-request-summary

#!/usr/bin/env python
#
# Print out a summary of the pull request.
#
# This combines the commit messages and removes the hard wrapping so the text renders better in
# Github's UI. The output won't be suitable as is, but provides a good start for moulding into a
# good description.

import subprocess


def main(target_branch: str) -> str:
    """
    Return a summary of the pull request.
    """
    # Grab full commit bodies.
    process = subprocess.Popen(
        ["git", "log", f"{target_branch}..", "--format=%B"],
        stdout=subprocess.PIPE,
        stderr=subprocess.PIPE,
        universal_newlines=True,
    )
    stdout, stderr = process.communicate()

    # Group paragraphs
    combined_lines = []
    combined_line_parts = []
    for line in stdout.split("\n"):
        if line:
            combined_line_parts.append(line)
        else:
            combined_lines.append(" ".join(combined_line_parts))
            combined_line_parts = []

    # If only one commit, we skip first line as that will be the PR subject.
    num_commits = _num_commits(target_branch)
    if num_commits == 1:
        combined_lines = combined_lines[1:]

    return "\n\n".join(combined_lines)


def _num_commits(target_branch: str) -> int:
    """
    Return the number of commits in this pull request.
    """
    return int(subprocess.getoutput(f"git log {target_branch}.. --oneline | wc -l"))


if __name__ == "__main__":
    print(main(target_branch="origin/master"))