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)

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from __future__ import absolute_import

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from mercurial.i18n import _

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from mercurial import (

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    hg,

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    registrar,

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)

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from mercurial.utils import (

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    urlutil,

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)

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cmdtable = {}

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command = registrar.command(cmdtable)

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@command(b'getflogheads', [], b'path')

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def getflogheads(ui, repo, path):

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    """

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    Extension printing a remotefilelog's heads

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    Used for testing purpose

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    """

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    dest = urlutil.get_unique_pull_path(b'getflogheads', repo, ui)[0]

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    peer = hg.peer(repo, {}, dest)

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    try:

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        flogheads = peer.x_rfl_getflogheads(path)

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    finally:

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        peer.close()

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    if flogheads:

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        for head in flogheads:

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            ui.write(head + b'\n')

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    else:

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        ui.write(_(b'EMPTY\n'))