comparison mercurial/copies.py @ 41756:49ad315b39ee

copies: do copy tracing based on ctx.p[12]copies() if configured

This adds an option to do copy tracing in a changeset-optimized
way. If the metadata is stored in filelogs, this is obviously going to
be suboptimal. The point is that it provides a way of transitioning to
changeset-stored metadata.

Some of the tests behave a little differently, but they all seem
resonable to me.

The config option may very well be renamed later when it's clearer
what options we want and how they will behave.

When the test suite is run with --extra-config-opt to use the new copy
tracing, all tests pass, besides test-copies.t (which fails in the
same way as you can see in this patch).

`hg debugpathcopies 4.0 4.8` reports 82 copies. With this option
enabled, the only difference is this:

  -mercurial/pure/bdiff.py -> mercurial/cffi/bdiff.py
  +setup_bdiff_cffi.py -> mercurial/cffi/bdiff.py

I believe that happened because it was renamed in different ways on
different sides of a merge and the new algorithm arbitrarily prefers
copies that happened on p1. The runtime is about 0.85 seconds with the
old copy tracing and 5.7 seconds with the new copy tracing. That's
kind of slow, but actually better than I had expected.

Differential Revision: https://phab.mercurial-scm.org/D5991

41755:a4358f7345b4

def _committedforwardcopies(a, b, match):
    """Like _forwardcopies(), but b.rev() cannot be None (working copy)"""
    # files might have to be traced back to the fctx parent of the last
    # one-side-only changeset, but not further back than that
    repo = a._repo
    debug = repo.ui.debugflag and repo.ui.configbool('devel', 'debug.copies')
    dbg = repo.ui.debug
    if debug:
        dbg('debug.copies:    looking into rename from %s to %s\n'
            % (a, b))

            cm[f] = ofctx.path()
        if debug:
            dbg('debug.copies:          time: %f seconds\n'
                % (util.timer() - start))
    return cm

def _forwardcopies(a, b, match=None):
    """find {dst@b: src@a} copy mapping where a is an ancestor of b"""

    match = a.repo().narrowmatch(match)

41756:49ad315b39ee

def _committedforwardcopies(a, b, match):
    """Like _forwardcopies(), but b.rev() cannot be None (working copy)"""
    # files might have to be traced back to the fctx parent of the last
    # one-side-only changeset, but not further back than that
    repo = a._repo

    if repo.ui.config('experimental', 'copies.read-from') == 'compatibility':
        return _changesetforwardcopies(a, b, match)

    debug = repo.ui.debugflag and repo.ui.configbool('devel', 'debug.copies')
    dbg = repo.ui.debug
    if debug:
        dbg('debug.copies:    looking into rename from %s to %s\n'
            % (a, b))

            cm[f] = ofctx.path()
        if debug:
            dbg('debug.copies:          time: %f seconds\n'
                % (util.timer() - start))
    return cm

def _changesetforwardcopies(a, b, match):
    if a.rev() == node.nullrev:
        return {}

    repo = a.repo()
    children = {}
    cl = repo.changelog
    missingrevs = cl.findmissingrevs(common=[a.rev()], heads=[b.rev()])
    for r in missingrevs:
        for p in cl.parentrevs(r):
            if p == node.nullrev:
                continue
            if p not in children:
                children[p] = [r]
            else:
                children[p].append(r)

    roots = set(children) - set(missingrevs)
    # 'work' contains 3-tuples of a (revision number, parent number, copies).
    # The parent number is only used for knowing which parent the copies dict
    # came from.
    work = [(r, 1, {}) for r in roots]
    heapq.heapify(work)
    while work:
        r, i1, copies1 = heapq.heappop(work)
        if work and work[0][0] == r:
            # We are tracing copies from both parents
            r, i2, copies2 = heapq.heappop(work)
            copies = {}
            ctx = repo[r]
            p1man, p2man = ctx.p1().manifest(), ctx.p2().manifest()
            allcopies = set(copies1) | set(copies2)
            # TODO: perhaps this filtering should be done as long as ctx
            # is merge, whether or not we're tracing from both parent.
            for dst in allcopies:
                if not match(dst):
                    continue
                if dst not in copies2:
                    # Copied on p1 side: mark as copy from p1 side if it didn't
                    # already exist on p2 side
                    if dst not in p2man:
                        copies[dst] = copies1[dst]
                elif dst not in copies1:
                    # Copied on p2 side: mark as copy from p2 side if it didn't
                    # already exist on p1 side
                    if dst not in p1man:
                        copies[dst] = copies2[dst]
                else:
                    # Copied on both sides: mark as copy from p1 side
                    copies[dst] = copies1[dst]
        else:
            copies = copies1
        if r == b.rev():
            return copies
        for c in children[r]:
            childctx = repo[c]
            if r == childctx.p1().rev():
                parent = 1
                childcopies = childctx.p1copies()
            else:
                assert r == childctx.p2().rev()
                parent = 2
                childcopies = childctx.p2copies()
            if not match.always():
                childcopies = {dst: src for dst, src in childcopies.items()
                               if match(dst)}
            childcopies = _chain(a, childctx, copies, childcopies)
            heapq.heappush(work, (c, parent, childcopies))
    assert False

def _forwardcopies(a, b, match=None):
    """find {dst@b: src@a} copy mapping where a is an ancestor of b"""

    match = a.repo().narrowmatch(match)