bundle2: move part iterator a separate class
Currently, the part iterator logic is tightly coupled with the part handling
logic, which means it's hard to replace the part handling logic without
duplicating the part iterator bits.
In a future diff we'll want to be able to replace all part handling, so let's
begin refactoring the part iterator logic to it's own class.
Differential Revision: https://phab.mercurial-scm.org/D703
# copies.py - copy detection for Mercurial
#
# Copyright 2008 Matt Mackall <mpm@selenic.com>
#
# 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 (
match as matchmod,
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()
return mb.filesnotin(ma, match=match)
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 b.p1() == a and b.p2().node() == node.nullid:
filesmatcher = scmutil.matchfiles(a._repo, b.files())
forwardmissingmatch = matchmod.intersectmatchers(match, filesmatcher)
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.config('experimental', 'copytrace') == 'off':
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 n in node.wdirnodes: # 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):
"""
The function calling different copytracing algorithms on the basis of config
which find moves and copies between context c1 and c2 that are relevant for
merging. 'base' will be used as the merge base.
Copytracing is used in commands like rebase, merge, unshelve, etc to merge
files that were moved/ copied in one merge parent and modified in another.
For example:
o ---> 4 another commit
|
| o ---> 3 commit that modifies a.txt
| /
o / ---> 2 commit that moves a.txt to b.txt
|/
o ---> 1 merge base
If we try to rebase revision 3 on revision 4, since there is no a.txt in
revision 4, and if user have copytrace disabled, we prints the following
message:
```other changed <file> which local deleted```
Returns five dicts: "copy", "movewithdir", "diverge", "renamedelete" and
"dirmove".
"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.
"dirmove" is a mapping of detected source dir -> destination dir renames.
This is needed for handling changes to new files previously grafted into
renamed directories.
"""
# 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(), {}, {}, {}, {}
copytracing = repo.ui.config('experimental', 'copytrace')
# 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 copytracing == 'off':
return {}, {}, {}, {}, {}
else:
return _fullcopytracing(repo, c1, c2, base)
def _fullcopytracing(repo, c1, c2, base):
""" The full copytracing algorithm which finds all the new files that were
added from merge base up to the top commit and for each file it checks if
this file was copied from another file.
This is pretty slow when a lot of changesets are involved but will track all
the copies.
"""
# 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, c2, f, base, tca, dirtyc1, limit, data1)
for f in u2u:
_checkcopies(c2, c1, f, base, tca, dirtyc2, limit, data2)
copy = dict(data1['copy'])
copy.update(data2['copy'])
fullcopy = dict(data1['fullcopy'])
fullcopy.update(data2['fullcopy'])
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, c2, f, base, tca, dirtyc1, limit, both1)
_checkcopies(c2, c1, f, 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, dirmove
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(srcctx, dstctx, f, base, tca, remotebase, limit, data):
"""
check possible copies of f from msrc to mdst
srcctx = starting context for f in msrc
dstctx = destination context for f in mdst
f = the filename to check (as in msrc)
base = the changectx used as a merge base
tca = topological common ancestor for graft-like scenarios
remotebase = True if base is outside tca::srcctx, 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 provides no guarantee that
irrelevant revisions will not be visited
there is no easy way to make this algorithm stop in a guaranteed way
once it "goes behind a certain revision".
"""
msrc = srcctx.manifest()
mdst = dstctx.manifest()
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
getsrcfctx = _makegetfctx(srcctx)
getdstfctx = _makegetfctx(dstctx)
if msrc[f] == mb.get(f) and not remotebase:
# Nothing to merge
return
of = None
seen = {f}
for oc in getsrcfctx(f, msrc[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 mdst:
continue # no match, keep looking
if mdst[of] == mb.get(of):
return # no merge needed, quit early
c2 = getdstfctx(of, mdst[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
repo.ui.config('experimental', 'copytrace') != 'off'):
# copytrace='off' 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)