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dirstate: ignore symlinks when fs cannot handle them (issue1888)...
dirstate: ignore symlinks when fs cannot handle them (issue1888) When the filesystem cannot handle the executable bit, we currently ignore it completely when looking for modified files. Similarly, it is impossible to set or clear the bit when the filesystem ignores it. This patch makes Mercurial treat symbolic links the same way. Symlinks are a little different since they manifest themselves as small files containing a filename (the symlink target). On Windows, these files show up as regular files, and on Linux and Mac they show up as real symlinks. Issue1888 presents a case where the symlink files are better ignored from the Windows side. A Linux client creates symlinks in a working copy which is shared over a network between Linux and Windows clients. The Samba server is helpful and defererences the symlink when the Windows client looks at it. This means that Mercurial on the Windows side sees file content instead of a file name in the symlink, and hence flags the link as modified. Ignoring the change would be much more helpful, similarly to how Mercurial does not report any changes when executable bits are ignored in a checkout on Windows. An initial checkout of a symbolic link on a file system that cannot handle symbolic links will still result in a regular file containing the target file name as its content. Sharing such a checkout with a Linux client will not turn the file into a symlink automatically, but 'hg revert' can fix that. After the revert, the Windows client will see the correct file content (provided by the Samba server when it follows the link on the Linux side) and otherwise ignore the change. Running 'hg perfstatus' 10 times gives these results: Before: After: min: 0.544703 min: 0.546549 med: 0.547592 med: 0.548881 avg: 0.549146 avg: 0.548549 max: 0.564112 max: 0.551504 The median time is increased about 0.24%.

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copies.py
267 lines | 8.0 KiB | text/x-python | PythonLexer
# 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.
import util
import heapq
def _nonoverlap(d1, d2, d3):
"Return list of elements in d1 not in d2 or d3"
return sorted([d for d in d1 if d not in d3 and d not in d2])
def _dirname(f):
s = f.rfind("/")
if s == -1:
return ""
return f[:s]
def _dirs(files):
d = set()
for f in files:
f = _dirname(f)
while f not in d:
d.add(f)
f = _dirname(f)
return d
def _findlimit(repo, a, b):
"""Find the earliest revision that's an ancestor of a or b but not both,
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
return limit
def copies(repo, c1, c2, ca, checkdirs=False):
"""
Find moves and copies between context c1 and c2
"""
# 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.parents()[0]:
return repo.dirstate.copies(), {}
limit = _findlimit(repo, c1.rev(), c2.rev())
if limit is None:
# no common ancestor, no copies
return {}, {}
m1 = c1.manifest()
m2 = c2.manifest()
ma = ca.manifest()
def makectx(f, n):
if len(n) != 20: # in a working context?
if c1.rev() is None:
return c1.filectx(f)
return c2.filectx(f)
return repo.filectx(f, fileid=n)
ctx = util.lrucachefunc(makectx)
copy = {}
fullcopy = {}
diverge = {}
def related(f1, f2, limit):
# 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.rev(), f2.rev()
if f1r is None:
f1 = g1.next()
if f2r is None:
f2 = g2.next()
while 1:
f1r, f2r = f1.rev(), f2.rev()
if f1r > f2r:
f1 = g1.next()
elif f2r > f1r:
f2 = g2.next()
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(f, m1, m2):
'''check possible copies of f from m1 to m2'''
of = None
seen = set([f])
for oc in ctx(f, m1[f]).ancestors():
ocr = oc.rev()
of = oc.path()
if of in seen:
# check limit late - grab last rename before
if ocr < limit:
break
continue
seen.add(of)
fullcopy[f] = of # remember for dir rename detection
if of not in m2:
continue # no match, keep looking
if m2[of] == ma.get(of):
break # no merge needed, quit early
c2 = ctx(of, m2[of])
cr = related(oc, c2, ca.rev())
if cr and (of == f or of == c2.path()): # non-divergent
copy[f] = of
of = None
break
if of in ma:
diverge.setdefault(of, []).append(f)
repo.ui.debug(" searching for copies back to rev %d\n" % limit)
u1 = _nonoverlap(m1, m2, ma)
u2 = _nonoverlap(m2, m1, ma)
if u1:
repo.ui.debug(" unmatched files in local:\n %s\n"
% "\n ".join(u1))
if u2:
repo.ui.debug(" unmatched files in other:\n %s\n"
% "\n ".join(u2))
for f in u1:
checkcopies(f, m1, m2)
for f in u2:
checkcopies(f, m2, m1)
diverge2 = set()
for of, fl in diverge.items():
if len(fl) == 1:
del diverge[of] # not actually divergent
else:
diverge2.update(fl) # reverse map for below
if fullcopy:
repo.ui.debug(" all copies found (* = to merge, ! = divergent):\n")
for f in fullcopy:
note = ""
if f in copy:
note += "*"
if f in diverge2:
note += "!"
repo.ui.debug(" %s -> %s %s\n" % (f, fullcopy[f], note))
del diverge2
if not fullcopy or not checkdirs:
return copy, diverge
repo.ui.debug(" checking for directory renames\n")
# generate a directory move map
d1, d2 = _dirs(m1), _dirs(m2)
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 = _dirname(src), _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
for d in dirmove:
repo.ui.debug(" dir %s -> %s\n" % (d, dirmove[d]))
# check unaccounted nonoverlapping files against directory moves
for f in u1 + u2:
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:
copy[f] = df
repo.ui.debug(" file %s -> %s\n" % (f, copy[f]))
break
return copy, diverge