view mercurial/ancestor.py @ 17658:a02c1ffddae9 stable

largefiles: handle commit -A properly, after a --large commit (issue3542)

Previous to this, 'commit -A' would add as normal files, files that were already
committed as largefiles, resulting in files being listed twice by 'status -A'.
It also missed when (only) a largefile was deleted, even though status reported
it as '!'.  This also has the side effect of properly reporting the state of the
affected largefiles in the post commit hook after a remove that also affected a
normal file (the largefiles used to be 'R', now are properly absent).

Since scmutil.addremove() is called both by the ui command (after some trivial
argument validation) and during the commit process when -A is specified, it
seems like a more appropriate method to wrap than the addremove command.

Currently, a repo is only enabled to use largefiles after an add that explicitly
identifies some file as large, and a subsequent commit.  Therefore, this patch
only changes behavior after such a largefile enabling commit.

Note that in the test, if the final commit had a '-v', 'removing large8' would
be printed twice.  Both of these originate in removelargefiles().  The first
print is in verbose mode after traversing remove + forget, the second is because
the '_isaddremove' attr is set and 'after' is not.

# ancestor.py - generic DAG ancestor algorithm for mercurial
#
# Copyright 2006 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

import heapq

def ancestor(a, b, pfunc):
    """
    Returns the common ancestor of a and b that is furthest from a
    root (as measured by longest path) or None if no ancestor is
    found. If there are multiple common ancestors at the same
    distance, the first one found is returned.

    pfunc must return a list of parent vertices for a given vertex
    """

    if a == b:
        return a

    a, b = sorted([a, b])

    # find depth from root of all ancestors
    # depth is stored as a negative for heapq
    parentcache = {}
    visit = [a, b]
    depth = {}
    while visit:
        vertex = visit[-1]
        pl = pfunc(vertex)
        parentcache[vertex] = pl
        if not pl:
            depth[vertex] = 0
            visit.pop()
        else:
            for p in pl:
                if p == a or p == b: # did we find a or b as a parent?
                    return p # we're done
                if p not in depth:
                    visit.append(p)
            if visit[-1] == vertex:
                # -(maximum distance of parents + 1)
                depth[vertex] = min([depth[p] for p in pl]) - 1
                visit.pop()

    # traverse ancestors in order of decreasing distance from root
    def ancestors(vertex):
        h = [(depth[vertex], vertex)]
        seen = set()
        while h:
            d, n = heapq.heappop(h)
            if n not in seen:
                seen.add(n)
                yield (d, n)
                for p in parentcache[n]:
                    heapq.heappush(h, (depth[p], p))

    def generations(vertex):
        sg, s = None, set()
        for g, v in ancestors(vertex):
            if g != sg:
                if sg:
                    yield sg, s
                sg, s = g, set((v,))
            else:
                s.add(v)
        yield sg, s

    x = generations(a)
    y = generations(b)
    gx = x.next()
    gy = y.next()

    # increment each ancestor list until it is closer to root than
    # the other, or they match
    try:
        while True:
            if gx[0] == gy[0]:
                for v in gx[1]:
                    if v in gy[1]:
                        return v
                gy = y.next()
                gx = x.next()
            elif gx[0] > gy[0]:
                gy = y.next()
            else:
                gx = x.next()
    except StopIteration:
        return None