# copies.py - copy detection for Mercurial # # Copyright 2008 Matt Mackall # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import import heapq from . import ( node, pathutil, scmutil, util, ) def _findlimit(repo, a, b): """ Find the last revision that needs to be checked to ensure that a full transitive closure for file copies can be properly calculated. Generally, this means finding the earliest revision number that's an ancestor of a or b but not both, except when a or b is a direct descendent of the other, in which case we can return the minimum revnum of a and b. None if no such revision exists. """ # basic idea: # - mark a and b with different sides # - if a parent's children are all on the same side, the parent is # on that side, otherwise it is on no side # - walk the graph in topological order with the help of a heap; # - add unseen parents to side map # - clear side of any parent that has children on different sides # - track number of interesting revs that might still be on a side # - track the lowest interesting rev seen # - quit when interesting revs is zero cl = repo.changelog working = len(cl) # pseudo rev for the working directory if a is None: a = working if b is None: b = working side = {a: -1, b: 1} visit = [-a, -b] heapq.heapify(visit) interesting = len(visit) hascommonancestor = False limit = working while interesting: r = -heapq.heappop(visit) if r == working: parents = [cl.rev(p) for p in repo.dirstate.parents()] else: parents = cl.parentrevs(r) for p in parents: if p < 0: continue if p not in side: # first time we see p; add it to visit side[p] = side[r] if side[p]: interesting += 1 heapq.heappush(visit, -p) elif side[p] and side[p] != side[r]: # p was interesting but now we know better side[p] = 0 interesting -= 1 hascommonancestor = True if side[r]: limit = r # lowest rev visited interesting -= 1 if not hascommonancestor: return None # Consider the following flow (see test-commit-amend.t under issue4405): # 1/ File 'a0' committed # 2/ File renamed from 'a0' to 'a1' in a new commit (call it 'a1') # 3/ Move back to first commit # 4/ Create a new commit via revert to contents of 'a1' (call it 'a1-amend') # 5/ Rename file from 'a1' to 'a2' and commit --amend 'a1-msg' # # During the amend in step five, we will be in this state: # # @ 3 temporary amend commit for a1-amend # | # o 2 a1-amend # | # | o 1 a1 # |/ # o 0 a0 # # When _findlimit is called, a and b are revs 3 and 0, so limit will be 2, # yet the filelog has the copy information in rev 1 and we will not look # back far enough unless we also look at the a and b as candidates. # This only occurs when a is a descendent of b or visa-versa. return min(limit, a, b) def _chain(src, dst, a, b): '''chain two sets of copies a->b''' t = a.copy() for k, v in b.iteritems(): if v in t: # found a chain if t[v] != k: # file wasn't renamed back to itself t[k] = t[v] if v not in dst: # chain was a rename, not a copy del t[v] if v in src: # file is a copy of an existing file t[k] = v # remove criss-crossed copies for k, v in t.items(): if k in src and v in dst: del t[k] return t def _tracefile(fctx, am, limit=-1): '''return file context that is the ancestor of fctx present in ancestor manifest am, stopping after the first ancestor lower than limit''' for f in fctx.ancestors(): if am.get(f.path(), None) == f.filenode(): return f if limit >= 0 and f.linkrev() < limit and f.rev() < limit: return None def _dirstatecopies(d): ds = d._repo.dirstate c = ds.copies().copy() for k in c.keys(): if ds[k] not in 'anm': del c[k] return c def _computeforwardmissing(a, b, match=None): """Computes which files are in b but not a. This is its own function so extensions can easily wrap this call to see what files _forwardcopies is about to process. """ ma = a.manifest() mb = b.manifest() if match: ma = ma.matches(match) mb = mb.matches(match) return mb.filesnotin(ma) def _forwardcopies(a, b, match=None): '''find {dst@b: src@a} copy mapping where a is an ancestor of b''' # check for working copy w = None if b.rev() is None: w = b b = w.p1() if a == b: # short-circuit to avoid issues with merge states return _dirstatecopies(w) # files might have to be traced back to the fctx parent of the last # one-side-only changeset, but not further back than that limit = _findlimit(a._repo, a.rev(), b.rev()) if limit is None: limit = -1 am = a.manifest() # find where new files came from # we currently don't try to find where old files went, too expensive # this means we can miss a case like 'hg rm b; hg cp a b' cm = {} # Computing the forward missing is quite expensive on large manifests, since # it compares the entire manifests. We can optimize it in the common use # case of computing what copies are in a commit versus its parent (like # during a rebase or histedit). Note, we exclude merge commits from this # optimization, since the ctx.files() for a merge commit is not correct for # this comparison. forwardmissingmatch = match if not match and b.p1() == a and b.p2().node() == node.nullid: forwardmissingmatch = scmutil.matchfiles(a._repo, b.files()) missing = _computeforwardmissing(a, b, match=forwardmissingmatch) ancestrycontext = a._repo.changelog.ancestors([b.rev()], inclusive=True) for f in missing: fctx = b[f] fctx._ancestrycontext = ancestrycontext ofctx = _tracefile(fctx, am, limit) if ofctx: cm[f] = ofctx.path() # combine copies from dirstate if necessary if w is not None: cm = _chain(a, w, cm, _dirstatecopies(w)) return cm def _backwardrenames(a, b): if a._repo.ui.configbool('experimental', 'disablecopytrace'): return {} # Even though we're not taking copies into account, 1:n rename situations # can still exist (e.g. hg cp a b; hg mv a c). In those cases we # arbitrarily pick one of the renames. f = _forwardcopies(b, a) r = {} for k, v in sorted(f.iteritems()): # remove copies if v in a: continue r[v] = k return r def pathcopies(x, y, match=None): '''find {dst@y: src@x} copy mapping for directed compare''' if x == y or not x or not y: return {} a = y.ancestor(x) if a == x: return _forwardcopies(x, y, match=match) if a == y: return _backwardrenames(x, y) return _chain(x, y, _backwardrenames(x, a), _forwardcopies(a, y, match=match)) def _computenonoverlap(repo, c1, c2, addedinm1, addedinm2, baselabel=''): """Computes, based on addedinm1 and addedinm2, the files exclusive to c1 and c2. This is its own function so extensions can easily wrap this call to see what files mergecopies is about to process. Even though c1 and c2 are not used in this function, they are useful in other extensions for being able to read the file nodes of the changed files. "baselabel" can be passed to help distinguish the multiple computations done in the graft case. """ u1 = sorted(addedinm1 - addedinm2) u2 = sorted(addedinm2 - addedinm1) header = " unmatched files in %s" if baselabel: header += ' (from %s)' % baselabel if u1: repo.ui.debug("%s:\n %s\n" % (header % 'local', "\n ".join(u1))) if u2: repo.ui.debug("%s:\n %s\n" % (header % 'other', "\n ".join(u2))) return u1, u2 def _makegetfctx(ctx): """return a 'getfctx' function suitable for _checkcopies usage We have to re-setup the function building 'filectx' for each '_checkcopies' to ensure the linkrev adjustment is properly setup for each. Linkrev adjustment is important to avoid bug in rename detection. Moreover, having a proper '_ancestrycontext' setup ensures the performance impact of this adjustment is kept limited. Without it, each file could do a full dag traversal making the time complexity of the operation explode (see issue4537). This function exists here mostly to limit the impact on stable. Feel free to refactor on default. """ rev = ctx.rev() repo = ctx._repo ac = getattr(ctx, '_ancestrycontext', None) if ac is None: revs = [rev] if rev is None: revs = [p.rev() for p in ctx.parents()] ac = repo.changelog.ancestors(revs, inclusive=True) ctx._ancestrycontext = ac def makectx(f, n): if len(n) != 20: # in a working context? if ctx.rev() is None: return ctx.filectx(f) return repo[None][f] fctx = repo.filectx(f, fileid=n) # setup only needed for filectx not create from a changectx fctx._ancestrycontext = ac fctx._descendantrev = rev return fctx return util.lrucachefunc(makectx) def _combinecopies(copyfrom, copyto, finalcopy, diverge, incompletediverge): """combine partial copy paths""" remainder = {} for f in copyfrom: if f in copyto: finalcopy[copyto[f]] = copyfrom[f] del copyto[f] for f in incompletediverge: assert f not in diverge ic = incompletediverge[f] if ic[0] in copyto: diverge[f] = [copyto[ic[0]], ic[1]] else: remainder[f] = ic return remainder def mergecopies(repo, c1, c2, base): """ Find moves and copies between context c1 and c2 that are relevant for merging. 'base' will be used as the merge base. Returns four dicts: "copy", "movewithdir", "diverge", and "renamedelete". "copy" is a mapping from destination name -> source name, where source is in c1 and destination is in c2 or vice-versa. "movewithdir" is a mapping from source name -> destination name, where the file at source present in one context but not the other needs to be moved to destination by the merge process, because the other context moved the directory it is in. "diverge" is a mapping of source name -> list of destination names for divergent renames. "renamedelete" is a mapping of source name -> list of destination names for files deleted in c1 that were renamed in c2 or vice-versa. """ # avoid silly behavior for update from empty dir if not c1 or not c2 or c1 == c2: return {}, {}, {}, {} # avoid silly behavior for parent -> working dir if c2.node() is None and c1.node() == repo.dirstate.p1(): return repo.dirstate.copies(), {}, {}, {} # Copy trace disabling is explicitly below the node == p1 logic above # because the logic above is required for a simple copy to be kept across a # rebase. if repo.ui.configbool('experimental', 'disablecopytrace'): return {}, {}, {}, {} # In certain scenarios (e.g. graft, update or rebase), base can be # overridden We still need to know a real common ancestor in this case We # can't just compute _c1.ancestor(_c2) and compare it to ca, because there # can be multiple common ancestors, e.g. in case of bidmerge. Because our # caller may not know if the revision passed in lieu of the CA is a genuine # common ancestor or not without explicitly checking it, it's better to # determine that here. # # base.descendant(wc) and base.descendant(base) are False, work around that _c1 = c1.p1() if c1.rev() is None else c1 _c2 = c2.p1() if c2.rev() is None else c2 # an endpoint is "dirty" if it isn't a descendant of the merge base # if we have a dirty endpoint, we need to trigger graft logic, and also # keep track of which endpoint is dirty dirtyc1 = not (base == _c1 or base.descendant(_c1)) dirtyc2 = not (base== _c2 or base.descendant(_c2)) graft = dirtyc1 or dirtyc2 tca = base if graft: tca = _c1.ancestor(_c2) limit = _findlimit(repo, c1.rev(), c2.rev()) if limit is None: # no common ancestor, no copies return {}, {}, {}, {} repo.ui.debug(" searching for copies back to rev %d\n" % limit) m1 = c1.manifest() m2 = c2.manifest() mb = base.manifest() # gather data from _checkcopies: # - diverge = record all diverges in this dict # - copy = record all non-divergent copies in this dict # - fullcopy = record all copies in this dict # - incomplete = record non-divergent partial copies here # - incompletediverge = record divergent partial copies here diverge = {} # divergence data is shared incompletediverge = {} data1 = {'copy': {}, 'fullcopy': {}, 'incomplete': {}, 'diverge': diverge, 'incompletediverge': incompletediverge, } data2 = {'copy': {}, 'fullcopy': {}, 'incomplete': {}, 'diverge': diverge, 'incompletediverge': incompletediverge, } # find interesting file sets from manifests addedinm1 = m1.filesnotin(mb) addedinm2 = m2.filesnotin(mb) bothnew = sorted(addedinm1 & addedinm2) if tca == base: # unmatched file from base u1r, u2r = _computenonoverlap(repo, c1, c2, addedinm1, addedinm2) u1u, u2u = u1r, u2r else: # unmatched file from base (DAG rotation in the graft case) u1r, u2r = _computenonoverlap(repo, c1, c2, addedinm1, addedinm2, baselabel='base') # unmatched file from topological common ancestors (no DAG rotation) # need to recompute this for directory move handling when grafting mta = tca.manifest() u1u, u2u = _computenonoverlap(repo, c1, c2, m1.filesnotin(mta), m2.filesnotin(mta), baselabel='topological common ancestor') for f in u1u: _checkcopies(c1, f, m1, m2, base, tca, dirtyc1, limit, data1) for f in u2u: _checkcopies(c2, f, m2, m1, base, tca, dirtyc2, limit, data2) copy = dict(data1['copy'].items() + data2['copy'].items()) fullcopy = dict(data1['fullcopy'].items() + data2['fullcopy'].items()) if dirtyc1: _combinecopies(data2['incomplete'], data1['incomplete'], copy, diverge, incompletediverge) else: _combinecopies(data1['incomplete'], data2['incomplete'], copy, diverge, incompletediverge) renamedelete = {} renamedeleteset = set() divergeset = set() for of, fl in diverge.items(): if len(fl) == 1 or of in c1 or of in c2: del diverge[of] # not actually divergent, or not a rename if of not in c1 and of not in c2: # renamed on one side, deleted on the other side, but filter # out files that have been renamed and then deleted renamedelete[of] = [f for f in fl if f in c1 or f in c2] renamedeleteset.update(fl) # reverse map for below else: divergeset.update(fl) # reverse map for below if bothnew: repo.ui.debug(" unmatched files new in both:\n %s\n" % "\n ".join(bothnew)) bothdiverge = {} bothincompletediverge = {} remainder = {} both1 = {'copy': {}, 'fullcopy': {}, 'incomplete': {}, 'diverge': bothdiverge, 'incompletediverge': bothincompletediverge } both2 = {'copy': {}, 'fullcopy': {}, 'incomplete': {}, 'diverge': bothdiverge, 'incompletediverge': bothincompletediverge } for f in bothnew: _checkcopies(c1, f, m1, m2, base, tca, dirtyc1, limit, both1) _checkcopies(c2, f, m2, m1, base, tca, dirtyc2, limit, both2) if dirtyc1: # incomplete copies may only be found on the "dirty" side for bothnew assert not both2['incomplete'] remainder = _combinecopies({}, both1['incomplete'], copy, bothdiverge, bothincompletediverge) elif dirtyc2: assert not both1['incomplete'] remainder = _combinecopies({}, both2['incomplete'], copy, bothdiverge, bothincompletediverge) else: # incomplete copies and divergences can't happen outside grafts assert not both1['incomplete'] assert not both2['incomplete'] assert not bothincompletediverge for f in remainder: assert f not in bothdiverge ic = remainder[f] if ic[0] in (m1 if dirtyc1 else m2): # backed-out rename on one side, but watch out for deleted files bothdiverge[f] = ic for of, fl in bothdiverge.items(): if len(fl) == 2 and fl[0] == fl[1]: copy[fl[0]] = of # not actually divergent, just matching renames if fullcopy and repo.ui.debugflag: repo.ui.debug(" all copies found (* = to merge, ! = divergent, " "% = renamed and deleted):\n") for f in sorted(fullcopy): note = "" if f in copy: note += "*" if f in divergeset: note += "!" if f in renamedeleteset: note += "%" repo.ui.debug(" src: '%s' -> dst: '%s' %s\n" % (fullcopy[f], f, note)) del divergeset if not fullcopy: return copy, {}, diverge, renamedelete repo.ui.debug(" checking for directory renames\n") # generate a directory move map d1, d2 = c1.dirs(), c2.dirs() # Hack for adding '', which is not otherwise added, to d1 and d2 d1.addpath('/') d2.addpath('/') invalid = set() dirmove = {} # examine each file copy for a potential directory move, which is # when all the files in a directory are moved to a new directory for dst, src in fullcopy.iteritems(): dsrc, ddst = pathutil.dirname(src), pathutil.dirname(dst) if dsrc in invalid: # already seen to be uninteresting continue elif dsrc in d1 and ddst in d1: # directory wasn't entirely moved locally invalid.add(dsrc + "/") elif dsrc in d2 and ddst in d2: # directory wasn't entirely moved remotely invalid.add(dsrc + "/") elif dsrc + "/" in dirmove and dirmove[dsrc + "/"] != ddst + "/": # files from the same directory moved to two different places invalid.add(dsrc + "/") else: # looks good so far dirmove[dsrc + "/"] = ddst + "/" for i in invalid: if i in dirmove: del dirmove[i] del d1, d2, invalid if not dirmove: return copy, {}, diverge, renamedelete for d in dirmove: repo.ui.debug(" discovered dir src: '%s' -> dst: '%s'\n" % (d, dirmove[d])) movewithdir = {} # check unaccounted nonoverlapping files against directory moves for f in u1r + u2r: if f not in fullcopy: for d in dirmove: if f.startswith(d): # new file added in a directory that was moved, move it df = dirmove[d] + f[len(d):] if df not in copy: movewithdir[f] = df repo.ui.debug((" pending file src: '%s' -> " "dst: '%s'\n") % (f, df)) break return copy, movewithdir, diverge, renamedelete def _related(f1, f2, limit): """return True if f1 and f2 filectx have a common ancestor Walk back to common ancestor to see if the two files originate from the same file. Since workingfilectx's rev() is None it messes up the integer comparison logic, hence the pre-step check for None (f1 and f2 can only be workingfilectx's initially). """ if f1 == f2: return f1 # a match g1, g2 = f1.ancestors(), f2.ancestors() try: f1r, f2r = f1.linkrev(), f2.linkrev() if f1r is None: f1 = next(g1) if f2r is None: f2 = next(g2) while True: f1r, f2r = f1.linkrev(), f2.linkrev() if f1r > f2r: f1 = next(g1) elif f2r > f1r: f2 = next(g2) elif f1 == f2: return f1 # a match elif f1r == f2r or f1r < limit or f2r < limit: return False # copy no longer relevant except StopIteration: return False def _checkcopies(ctx, f, m1, m2, base, tca, remotebase, limit, data): """ check possible copies of f from m1 to m2 ctx = starting context for f in m1 f = the filename to check (as in m1) m1 = the source manifest m2 = the destination manifest base = the changectx used as a merge base tca = topological common ancestor for graft-like scenarios remotebase = True if base is outside tca::ctx, False otherwise limit = the rev number to not search beyond data = dictionary of dictionary to store copy data. (see mergecopies) note: limit is only an optimization, and there is no guarantee that irrelevant revisions will not be limited there is no easy way to make this algorithm stop in a guaranteed way once it "goes behind a certain revision". """ mb = base.manifest() mta = tca.manifest() # Might be true if this call is about finding backward renames, # This happens in the case of grafts because the DAG is then rotated. # If the file exists in both the base and the source, we are not looking # for a rename on the source side, but on the part of the DAG that is # traversed backwards. # # In the case there is both backward and forward renames (before and after # the base) this is more complicated as we must detect a divergence. # We use 'backwards = False' in that case. backwards = not remotebase and base != tca and f in mb getfctx = _makegetfctx(ctx) of = None seen = set([f]) for oc in getfctx(f, m1[f]).ancestors(): ocr = oc.linkrev() of = oc.path() if of in seen: # check limit late - grab last rename before if ocr < limit: break continue seen.add(of) # remember for dir rename detection if backwards: data['fullcopy'][of] = f # grafting backwards through renames else: data['fullcopy'][f] = of if of not in m2: continue # no match, keep looking if m2[of] == mb.get(of): return # no merge needed, quit early c2 = getfctx(of, m2[of]) # c2 might be a plain new file on added on destination side that is # unrelated to the droids we are looking for. cr = _related(oc, c2, tca.rev()) if cr and (of == f or of == c2.path()): # non-divergent if backwards: data['copy'][of] = f elif of in mb: data['copy'][f] = of elif remotebase: # special case: a <- b <- a -> b "ping-pong" rename data['copy'][of] = f del data['fullcopy'][f] data['fullcopy'][of] = f else: # divergence w.r.t. graft CA on one side of topological CA for sf in seen: if sf in mb: assert sf not in data['diverge'] data['diverge'][sf] = [f, of] break return if of in mta: if backwards or remotebase: data['incomplete'][of] = f else: for sf in seen: if sf in mb: if tca == base: data['diverge'].setdefault(sf, []).append(f) else: data['incompletediverge'][sf] = [of, f] return def duplicatecopies(repo, rev, fromrev, skiprev=None): '''reproduce copies from fromrev to rev in the dirstate If skiprev is specified, it's a revision that should be used to filter copy records. Any copies that occur between fromrev and skiprev will not be duplicated, even if they appear in the set of copies between fromrev and rev. ''' exclude = {} if (skiprev is not None and not repo.ui.configbool('experimental', 'disablecopytrace')): # disablecopytrace skips this line, but not the entire function because # the line below is O(size of the repo) during a rebase, while the rest # of the function is much faster (and is required for carrying copy # metadata across the rebase anyway). exclude = pathcopies(repo[fromrev], repo[skiprev]) for dst, src in pathcopies(repo[fromrev], repo[rev]).iteritems(): # copies.pathcopies returns backward renames, so dst might not # actually be in the dirstate if dst in exclude: continue if repo.dirstate[dst] in "nma": repo.dirstate.copy(src, dst)