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)

from __future__ import absolute_import
import os
from mercurial import (
    dispatch,
    extensions,
    ui as uimod,
)


def testdispatch(cmd):
    """Simple wrapper around dispatch.dispatch()

    Prints command and result value, but does not handle quoting.
    """
    ui = uimod.ui.load()
    extensions.populateui(ui)
    ui.statusnoi18n(b"running: %s\n" % cmd)
    req = dispatch.request(cmd.split(), ui)
    result = dispatch.dispatch(req)
    ui.statusnoi18n(b"result: %r\n" % result)


# create file 'foo', add and commit
f = open(b'foo', 'wb')
f.write(b'foo\n')
f.close()
testdispatch(b"--debug add foo")
testdispatch(b"--debug commit -m commit1 -d 2000-01-01 foo")

# append to file 'foo' and commit
f = open(b'foo', 'ab')
f.write(b'bar\n')
f.close()
# remove blackbox.log directory (proxy for readonly log file)
os.rmdir(b".hg/blackbox.log")
# replace it with the real blackbox.log file
os.rename(b".hg/blackbox.log-", b".hg/blackbox.log")
testdispatch(b"--debug commit -m commit2 -d 2000-01-02 foo")

# check 88803a69b24 (fancyopts modified command table)
testdispatch(b"--debug log -r 0")
testdispatch(b"--debug log -r tip")