python

import re

CASE_RE = r'^Case-(?P<case_id>\d+)'
MERGE_RE = r'^(merge|merged) (?P<branch_name>[\w-]+)'


def prefix_commit_message(repo, **kwargs):
    commitctx = repo.commitctx

    """
    Checks before commit when committing to default
    """
    if (repo[None].branch() == 'default' and
            raw_input('You are about to commit to the default '
                      'branch. Are you sure you wish to proceed? '
                      '([Y]/N) ') != 'y'):
        # hg expects a truthy value on failure, for some reason
        return True

    def rewrite_ctx(ctx, error):
        branch_name = ctx.branch()
        if branch_name == 'default':
            result = re.match(MERGE_RE, ctx._text)
            if result:
                merged = result.groups()[1]
                title = raw_input("Description: ")
                ctx._text = "%s: %s" % (merged, title)
        else:
            old_text = ctx._text
            old_text_lower = old_text.lower()

            if old_text_lower == 'mergeup':
                old_text = 'Merged upstream changes'
            elif old_text_lower == 'close':
                old_text = 'Request implemented; case closed'

            result = re.match(CASE_RE, branch_name)

            if result:
                branch_name = "Case %s" % result.groups()[0]
            ctx._text = "%s: %s" % (branch_name, old_text)
        return commitctx(ctx, error)

    repo.commitctx = rewrite_ctx