view tests/test-dispatch.py @ 47343:9f798c1b0d89 stable

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, print_function
import os
import sys
from mercurial import dispatch


def printb(data, end=b'\n'):
    out = getattr(sys.stdout, 'buffer', sys.stdout)
    out.write(data + end)
    out.flush()


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

    Prints command and result value, but does not handle quoting.
    """
    printb(b"running: %s" % (cmd,))
    req = dispatch.request(cmd.split())
    result = dispatch.dispatch(req)
    printb(b"result: %r" % (result,))


testdispatch(b"init test1")
os.chdir('test1')

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

# append to file 'foo' and commit
f = open('foo', 'ab')
f.write(b'bar\n')
f.close()
testdispatch(b"commit -m commit2 -d 2000-01-02 foo")

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