view tests/test-sparse-requirement.t @ 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)

  $ hg init repo
  $ cd repo

  $ touch a.html b.html c.py d.py

  $ cat > frontend.sparse << EOF
  > [include]
  > *.html
  > EOF

  $ hg -q commit -A -m initial

  $ echo 1 > a.html
  $ echo 1 > c.py
  $ hg commit -m 'commit 1'

Enable sparse profile

  $ cat .hg/requires
  dotencode
  fncache
  generaldelta
  persistent-nodemap (rust !)
  revlog-compression-zstd (zstd !)
  revlogv1
  sparserevlog
  store
  testonly-simplestore (reposimplestore !)

  $ hg debugsparse --config extensions.sparse= --enable-profile frontend.sparse
  $ ls -A
  .hg
  a.html
  b.html

Requirement for sparse added when sparse is enabled

  $ cat .hg/requires
  dotencode
  exp-sparse
  fncache
  generaldelta
  persistent-nodemap (rust !)
  revlog-compression-zstd (zstd !)
  revlogv1
  sparserevlog
  store
  testonly-simplestore (reposimplestore !)

Client without sparse enabled reacts properly

  $ hg files
  abort: repository is using sparse feature but sparse is not enabled; enable the "sparse" extensions to access
  [255]

Requirement for sparse is removed when sparse is disabled

  $ hg debugsparse --reset --config extensions.sparse=

  $ cat .hg/requires
  dotencode
  fncache
  generaldelta
  persistent-nodemap (rust !)
  revlog-compression-zstd (zstd !)
  revlogv1
  sparserevlog
  store
  testonly-simplestore (reposimplestore !)

And client without sparse can access

  $ hg files
  a.html
  b.html
  c.py
  d.py
  frontend.sparse