tests/printrevset.py

transaction: quietly rollback if no other changes than temporary files

If no actual change have been made, we don't really need to roll them back. We
only have to cleanup some temporary files and it seems reasonable to do that
quietly.

This will help us to use the transaction in wider context¹ without impacting the
user experience.

[1] as in Python context managers that lives longer.

from mercurial.thirdparty import attr
from mercurial import (
    cmdutil,
    commands,
    extensions,
    logcmdutil,
    revsetlang,
    smartset,
)

from mercurial.utils import stringutil


def logrevset(repo, wopts):
    revs = logcmdutil._initialrevs(repo, wopts)
    if not revs:
        return None
    match, pats, slowpath = logcmdutil._makematcher(repo, revs, wopts)
    wopts = attr.evolve(wopts, pats=pats)
    return logcmdutil._makerevset(repo, wopts, slowpath)


def uisetup(ui):
    def printrevset(orig, repo, wopts):
        revs, filematcher = orig(repo, wopts)
        if wopts.opts.get(b'print_revset'):
            expr = logrevset(repo, wopts)
            if expr:
                tree = revsetlang.parse(expr)
                tree = revsetlang.analyze(tree)
            else:
                tree = []
            ui = repo.ui
            ui.write(b'%s\n' % stringutil.pprint(wopts.opts.get(b'rev', [])))
            ui.write(revsetlang.prettyformat(tree) + b'\n')
            ui.write(stringutil.prettyrepr(revs) + b'\n')
            revs = smartset.baseset()  # display no revisions
        return revs, filematcher

    extensions.wrapfunction(logcmdutil, 'getrevs', printrevset)
    aliases, entry = cmdutil.findcmd(b'log', commands.table)
    entry[1].append(
        (
            b'',
            b'print-revset',
            False,
            b'print generated revset and exit (DEPRECATED)',
        )
    )