comparison mercurial/commands.py @ 20275:2123d27ff75d

backout: avoid update on simple case.

Before the changeset the backout process was:
1) go to <target>
2) revert to <target> parent
3) update back to changeset we came from

The two update steps can takes a very long time to move back and forth unrelated
file change between <target> and current working directory.

The new process is just merging current working directory with the parent of
<target> using <target> as ancestor. This give the very same result but skip
the two updates. On big repo with a lot of files and changes that save a lots of
time (x20 for one week window).

The "merge" version (hg backout --merge) is still done with upgrades. We could
imagine using in memory commit to speed it up but this is another fish.

20274:7a259dfe24f7

    # the backout should appear on the same branch
    wlock = repo.wlock()
    try:
        branch = repo.dirstate.branch()
        bheads = repo.branchheads(branch)
        hg.clean(repo, node, show_stats=False)
        repo.dirstate.setbranch(branch)
        rctx = scmutil.revsingle(repo, hex(parent))
        cmdutil.revert(ui, repo, rctx, repo.dirstate.parents())
        if not opts.get('merge') and op1 != node:
            try:
                ui.setconfig('ui', 'forcemerge', opts.get('tool', ''))
                return hg.update(repo, op1)
            finally:
                ui.setconfig('ui', 'forcemerge', '')

        e = cmdutil.commiteditor
        if not opts['message'] and not opts['logfile']:
            # we don't translate commit messages
            opts['message'] = "Backed out changeset %s" % short(node)

20275:2123d27ff75d

    # the backout should appear on the same branch
    wlock = repo.wlock()
    try:
        branch = repo.dirstate.branch()
        bheads = repo.branchheads(branch)
        rctx = scmutil.revsingle(repo, hex(parent))
        if not opts.get('merge') and op1 != node:
            try:
                ui.setconfig('ui', 'forcemerge', opts.get('tool', ''))
                stats = mergemod.update(repo, parent, True, True, False, node, False)
                repo.setparents(op1, op2)
                hg._showstats(repo, stats)
                if stats[3]:
                    repo.ui.status(_("use 'hg resolve' to retry unresolved file merges\n"))
                return stats[3] > 0
            finally:
                ui.setconfig('ui', 'forcemerge', '')
        else:
            hg.clean(repo, node, show_stats=False)
            repo.dirstate.setbranch(branch)
            cmdutil.revert(ui, repo, rctx, repo.dirstate.parents())


        e = cmdutil.commiteditor
        if not opts['message'] and not opts['logfile']:
            # we don't translate commit messages
            opts['message'] = "Backed out changeset %s" % short(node)