Avoid extra filelogs entries.
Right now, there are some situations in which localrepo.filecommit can
create filelog entries even though they're not needed. For example:
- permissions for a file have changed;
- qrefresh can create a filelog entry identical to its parent (see the
added test);
- convert-repo creates extra filelog entries in every merge where the
first parent has added files (for example, changeset ebebe9577a1a of
the kernel repo added extra filelog entries to files in the
arch/blackfin directory, even though the merge should only touch the
drivers/ata directory). This makes "hg log file" in a converted repo
less useful than it could be, since it may mention many merges that
don't actually touch that specific file.
They all come from the same basic problem: localrepo.commit (through
filecommit) creates new filelog entries for all files passed to it
(except for some cases during a merge).
Patch and test case provided by Benoit.
This should fix issue351.
# ancestor.py - generic DAG ancestor algorithm for mercurial
#
# Copyright 2006 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.
import heapq
def ancestor(a, b, pfunc):
"""
return the least common ancestor of nodes a and b or None if there
is no such ancestor.
pfunc must return a list of parent vertices
"""
if a == b:
return a
# find depth from root of all ancestors
visit = [a, b]
depth = {}
while visit:
vertex = visit[-1]
pl = pfunc(vertex)
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:
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 = {}
while h:
d, n = heapq.heappop(h)
if n not in seen:
seen[n] = 1
yield (d, n)
for p in pfunc(n):
heapq.heappush(h, (depth[p], p))
def generations(vertex):
sg, s = None, {}
for g, v in ancestors(vertex):
if g != sg:
if sg:
yield sg, s
sg, s = g, {v:1}
else:
s[v] = 1
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 1:
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