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)
$ hg init rep
$ cd rep
$ mkdir dir
$ touch foo dir/bar
$ hg -v addremove
adding dir/bar
adding foo
$ hg -v commit -m "add 1"
committing files:
dir/bar
foo
committing manifest
committing changelog
committed changeset 0:6f7f953567a2
$ cd dir/
$ touch ../foo_2 bar_2
$ hg -v addremove
adding dir/bar_2
adding foo_2
$ hg -v commit -m "add 2"
committing files:
dir/bar_2
foo_2
committing manifest
committing changelog
committed changeset 1:e65414bf35c5
$ cd ..
$ hg forget foo
$ hg -v addremove
adding foo
$ hg forget foo
$ hg -v addremove nonexistent
nonexistent: $ENOENT$
[1]
$ cd ..
$ hg init subdir
$ cd subdir
$ mkdir dir
$ cd dir
$ touch a.py
$ hg addremove 'glob:*.py'
adding a.py
$ hg forget a.py
$ hg addremove -I 'glob:*.py'
adding a.py
$ hg forget a.py
$ hg addremove
adding dir/a.py
$ cd ..
$ hg init sim
$ cd sim
$ echo a > a
$ echo a >> a
$ echo a >> a
$ echo c > c
$ hg commit -Ama
adding a
adding c
$ mv a b
$ rm c
$ echo d > d
$ hg addremove -n -s 50 # issue 1696
removing a
adding b
removing c
adding d
recording removal of a as rename to b (100% similar)
$ hg addremove -ns 50 --color debug
[ui.addremove.removed ui.status|removing a]
[ui.addremove.added ui.status|adding b]
[ui.addremove.removed ui.status|removing c]
[ui.addremove.added ui.status|adding d]
[ ui.status|recording removal of a as rename to b (100% similar)]
$ hg addremove -s 50
removing a
adding b
removing c
adding d
recording removal of a as rename to b (100% similar)
$ hg commit -mb
$ cp b c
$ hg forget b
$ hg addremove -s 50
adding b
adding c
$ rm c
$ hg ci -A -m "c" nonexistent
nonexistent: $ENOENT$
abort: failed to mark all new/missing files as added/removed
[255]
$ hg st
! c
$ cd ..