cext: fix memory leak in phases computation
Without this a buffer whose size in bytes is the number of
changesets in the repository is leaked each time the repository is
opened and changeset phases are computed.
Impact: the current code in hgwebdir creates a new `localrepository`
instance for each HTTP request. Since any pull or push is made of several
requests, a team of 100 people can easily produce thousands of such
requests per day.
Being a low-level malloc, this leak can't be seen with the gc module and
tools relying on that, but was spotted by valgrind immediately.
Reproduction
------------
for i in range(cl_args.iterations):
repo = hg.repository(baseui, repo_path)
rev = repo.revs(rev).first()
ctx = repo[rev]
del ctx
del repo
# avoid any pollution by other type of leak
# (that should be fixed in 5.8)
repoview._filteredrepotypes.clear()
gc.collect()
Measurements
------------
Resident Set Size (RSS), taken on a clone of
mozilla-central for performance analysis (440 000
changesets).
before:
5.8+hg19.5ac0f2a8ba72 1000 iterations: 1606MB
5.8+hg19.5ac0f2a8ba72 10000 iterations: 5723MB
after:
5.8+hg20.e2084d39e145 1000 iterations: 555MB
5.8+hg20.e2084d39e145 10000 iterations: 555MB
(double checked, not a copy/paste error)
(e2084d39e14 is the present changeset, before amendment
of the message to add the measurements)
#require no-windows
$ . "$TESTDIR/remotefilelog-library.sh"
$ hg init master
$ cd master
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> server=True
> EOF
$ echo x > x
$ hg commit -qAm x
$ cd ..
$ hgcloneshallow ssh://user@dummy/master shallow -q
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
$ cd master
$ echo xx > x
$ hg commit -qAm x2
$ cd ..
# Test cache misses with read only permissions on server
$ chmod -R a-w master/.hg/remotefilelogcache
$ cd shallow
$ hg pull -q
$ hg update
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
$ cd ..
$ chmod -R u+w master/.hg/remotefilelogcache
# Test setting up shared cache with the right permissions
# (this is hard to test in a cross platform way, so we just make sure nothing
# crashes)
$ rm -rf $CACHEDIR
$ umask 002
$ mkdir $CACHEDIR
$ hg -q clone --shallow ssh://user@dummy/master shallow2 --config remotefilelog.cachegroup="`id -g -n`"
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over * (glob)
$ ls -ld $CACHEDIR/11
drwxrws* $TESTTMP/hgcache/11 (glob)