contrib/check-commit

contrib: add a hint if the Windows dependency MSI is already installed

In the past, I've gotten confused when the script failed on seemingly random
python installs (and thus the py3.8 install was commented out from the last time
this happened to me, which has been reverted here).  This particular error code
means the package was already installed.  For python, it means the major and
minor version are the same, but the micro version may differ.

In practice, ignoring the python installation failure will cause the pip
installation that happens next to fail, because python.exe for that version is
somewhere else on the system.  This could probably be fixed by running py.exe
with the major and minor version, but that is skipped during the install for
some reason.  I didn't feel like over complicating this though, and at least
there's a better hint when the problem occurs.

Differential Revision: https://phab.mercurial-scm.org/D12560

#!/usr/bin/env python3
#
# Copyright 2014 Olivia Mackall <[e-mail]>
#
# A tool/hook to run basic sanity checks on commits/patches for
# submission to Mercurial. Install by adding the following to your
# .hg/hgrc:
#
# [hooks]
# pretxncommit = contrib/check-commit
#
# The hook can be temporarily bypassed with:
#
# $ BYPASS= hg commit
#
# See also: https://mercurial-scm.org/wiki/ContributingChanges


import os
import re
import sys

commitheader = r"^(?:# [^\n]*\n)*"
afterheader = commitheader + r"(?!#)"
beforepatch = afterheader + r"(?!\n(?!@@))"

errors = [
    (beforepatch + r".*[(]bc[)]", "(BC) needs to be uppercase"),
    (
        beforepatch + r".*[(]issue \d\d\d",
        "no space allowed between issue and number",
    ),
    (beforepatch + r".*[(]bug(\d|\s)", "use (issueDDDD) instead of bug"),
    (commitheader + r"# User [^@\n]+\n", "username is not an email address"),
    (
        commitheader + r"(?!merge with )[^#]\S+[^:] ",
        "summary line doesn't start with 'topic: '",
    ),
    (afterheader + r"[A-Z][a-z]\S+", "don't capitalize summary lines"),
    (afterheader + r"^\S+: *[A-Z][a-z]\S+", "don't capitalize summary lines"),
    (
        afterheader + r"\S*[^A-Za-z0-9-_]\S*: ",
        "summary keyword should be most user-relevant one-word command or topic",
    ),
    (afterheader + r".*\.\s*\n", "don't add trailing period on summary line"),
    (afterheader + r".{79,}", "summary line too long (limit is 78)"),
]

word = re.compile(r'\S')


def nonempty(first, second):
    if word.search(first):
        return first
    return second


def checkcommit(commit, node=None):
    exitcode = 0
    printed = node is None
    hits = []
    signtag = (
        afterheader + r'Added (tag [^ ]+|signature) for changeset [a-f0-9]{12}'
    )
    if re.search(signtag, commit):
        return 0
    for exp, msg in errors:
        for m in re.finditer(exp, commit):
            end = m.end()
            trailing = re.search(r'(\\n)+$', exp)
            if trailing:
                end -= len(trailing.group()) / 2
            hits.append((end, exp, msg))
    if hits:
        hits.sort()
        pos = 0
        last = ''
        for n, l in enumerate(commit.splitlines(True)):
            pos += len(l)
            while len(hits):
                end, exp, msg = hits[0]
                if pos < end:
                    break
                if not printed:
                    printed = True
                    print("node: %s" % node)
                print("%d: %s" % (n, msg))
                print(" %s" % nonempty(l, last)[:-1])
                if "BYPASS" not in os.environ:
                    exitcode = 1
                del hits[0]
            last = nonempty(l, last)

    return exitcode


def readcommit(node):
    return os.popen("hg export %s" % node).read()


if __name__ == "__main__":
    exitcode = 0
    node = os.environ.get("HG_NODE")

    if node:
        commit = readcommit(node)
        exitcode = checkcommit(commit)
    elif sys.argv[1:]:
        for node in sys.argv[1:]:
            exitcode |= checkcommit(readcommit(node), node)
    else:
        commit = sys.stdin.read()
        exitcode = checkcommit(commit)
    sys.exit(exitcode)