view tests/test-static-http.t @ 47010:76ae43d5b1db stable

repoview: fix memory leak of filtered repo classes

The leak occurs in long-running server processes with
extensions, and is measured at 110kB per request.

Before this change, the contents of the `_filteredrepotypes`
cache are not properly garbage collected, despite it begin
a `WeakKeyDictionary`.

Extensions have a tendency to generate a new repository class
for each `localrepo` instantiation. Server processes based
on `hgwebdir_mod` will instantiate a new `localrepo` for each
HTTP request that involves a repository.

As a result, with a testing process that repeatedly opens a
repository with several extensions activated
(`topic` notably among them), we see a steady increase in
resident memory of 110kB per repository instantiation before this
change. This is also true, if we call `gc.collect()` at each
instantiation, like `hgwebdir_mod` does, or not.

The cause of the leak is that the *values* aren't weak references.
This change uses `weakref.ref` for the values, and this makes
in our measurements the resident size increase drop to 5kB per
repository instantiation, with no explicit call of `gc.collect()`
at all.
There is currently no reason to believe that this remaining leak
of 5kB is related to or even due to Mercurial core.

We've also seen evidence that `ui.ui` instances weren't properly
garbage collected before the change (with the change, they are).
This could explain why the figures are relatively high.

In theory, the collection of weak references could lead to
much more misses in the cache, so we measured the impact on
the original case that was motivation for introducing that cache
in 7e89bd0cfb86 (see also issue5043): `hg convert` of the
mozilla-central repository. The bad news here is that there is a
major memory leak there, both with and without the present changeset.
There were no more cache misses, and we could see no
more memory leak with this change: the resident size after importing
roughly 100000 changesets was at 12.4GB before, and 12.5GB after.
The small increase is mentioned for completeness only, and we
believe that it should be ignored, at least as long as the main
leak isn't fixed. At less than 1% of the main leak, even finding out
whether it is merely noise would be wasteful.

Original context where this was spotted and first mitigated:
  https://foss.heptapod.net/heptapod/heptapod/-/issues/466

The leak reduction was also obtained in Heptapod inner HTTP server,
which amounts to the same as `hgwebdir_mod` for these questions.

The measurements done with Python 3.9, similar figures seen with 3.8.
More work on our side would be needed to give measurements with 2.7,
because of testing server process does not support it.

#require no-reposimplestore

  $ hg clone http://localhost:$HGPORT/ copy
  abort: * (glob)
  [100]
  $ test -d copy
  [1]

This server doesn't do range requests so it's basically only good for
one pull

  $ "$PYTHON" "$TESTDIR/dumbhttp.py" -p $HGPORT --pid dumb.pid \
  > --logfile server.log
  $ cat dumb.pid >> $DAEMON_PIDS
  $ hg init remote
  $ cd remote
  $ echo foo > bar
  $ echo c2 > '.dotfile with spaces'
  $ hg add
  adding .dotfile with spaces
  adding bar
  $ hg commit -m"test"
  $ hg tip
  changeset:   0:02770d679fb8
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     test
  
  $ cd ..
  $ hg clone static-http://localhost:$HGPORT/remote local
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  new changesets 02770d679fb8
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd local
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 1 changesets with 2 changes to 2 files
  $ cat bar
  foo
  $ cd ../remote
  $ echo baz > quux
  $ hg commit -A -mtest2
  adding quux

check for HTTP opener failures when cachefile does not exist

  $ rm .hg/cache/*
  $ cd ../local
  $ cat >> .hg/hgrc <<EOF
  > [hooks]
  > changegroup = sh -c "printenv.py --line changegroup"
  > EOF
  $ hg pull
  pulling from static-http://localhost:$HGPORT/remote
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets 4ac2e3648604
  changegroup hook: HG_HOOKNAME=changegroup
  HG_HOOKTYPE=changegroup
  HG_NODE=4ac2e3648604439c580c69b09ec9d93a88d93432
  HG_NODE_LAST=4ac2e3648604439c580c69b09ec9d93a88d93432
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  http://localhost:$HGPORT/remote
  HG_URL=http://localhost:$HGPORT/remote
  
  (run 'hg update' to get a working copy)

trying to push

  $ hg update
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo more foo >> bar
  $ hg commit -m"test"
  $ hg push
  pushing to static-http://localhost:$HGPORT/remote
  abort: destination does not support push
  [255]

trying clone -r

  $ cd ..
  $ hg clone -r doesnotexist static-http://localhost:$HGPORT/remote local0
  abort: unknown revision 'doesnotexist'
  [255]
  $ hg clone -r 0 static-http://localhost:$HGPORT/remote local0
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  new changesets 02770d679fb8
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

test with "/" URI (issue747) and subrepo

  $ hg init
  $ hg init sub
  $ touch sub/test
  $ hg -R sub commit -A -m "test"
  adding test
  $ hg -R sub tag not-empty
  $ echo sub=sub > .hgsub
  $ echo a > a
  $ hg add a .hgsub
  $ hg -q ci -ma
  $ hg clone static-http://localhost:$HGPORT/ local2
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 3 changes to 3 files
  new changesets a9ebfbe8e587
  updating to branch default
  cloning subrepo sub from static-http://localhost:$HGPORT/sub
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files
  new changesets be090ea66256:322ea90975df
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd local2
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 1 changesets with 3 changes to 3 files
  checking subrepo links
  $ cat a
  a
  $ hg paths
  default = static-http://localhost:$HGPORT/

test with empty repo (issue965)

  $ cd ..
  $ hg init remotempty
  $ hg clone static-http://localhost:$HGPORT/remotempty local3
  no changes found
  updating to branch default
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd local3
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 0 changesets with 0 changes to 0 files
  $ hg paths
  default = static-http://localhost:$HGPORT/remotempty

test with non-repo

  $ cd ..
  $ mkdir notarepo
  $ hg clone static-http://localhost:$HGPORT/notarepo local3
  abort: 'http://localhost:$HGPORT/notarepo' does not appear to be an hg repository
  [255]

Clone with tags and branches works

  $ hg init remote-with-names
  $ cd remote-with-names
  $ echo 0 > foo
  $ hg -q commit -A -m initial
  $ echo 1 > foo
  $ hg commit -m 'commit 1'
  $ hg -q up 0
  $ hg branch mybranch
  marked working directory as branch mybranch
  (branches are permanent and global, did you want a bookmark?)
  $ echo 2 > foo
  $ hg commit -m 'commit 2 (mybranch)'
  $ hg tag -r 1 'default-tag'
  $ hg tag -r 2 'branch-tag'

  $ cd ..

  $ hg clone static-http://localhost:$HGPORT/remote-with-names local-with-names
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 5 changes to 2 files (+1 heads)
  new changesets 68986213bd44:0c325bd2b5a7
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

Clone a specific branch works

  $ hg clone -r mybranch static-http://localhost:$HGPORT/remote-with-names local-with-names-branch
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 4 changes to 2 files
  new changesets 68986213bd44:0c325bd2b5a7
  updating to branch mybranch
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

Clone a specific tag works

  $ hg clone -r default-tag static-http://localhost:$HGPORT/remote-with-names local-with-names-tag
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  new changesets 68986213bd44:4ee3fcef1c80
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ killdaemons.py

List of files accessed over HTTP:

  $ cat server.log | sed -n -e 's|.*GET \(/[^ ]*\).*|\1|p' | sort -u
  /.hg/bookmarks
  /.hg/bookmarks.current
  /.hg/cache/hgtagsfnodes1
  /.hg/dirstate
  /.hg/requires
  /.hg/store/00changelog.i
  /.hg/store/00manifest.i
  /.hg/store/data/%7E2ehgsub.i (no-py37 !)
  /.hg/store/data/%7E2ehgsubstate.i (no-py37 !)
  /.hg/store/data/a.i
  /.hg/store/data/~2ehgsub.i (py37 !)
  /.hg/store/data/~2ehgsubstate.i (py37 !)
  /notarepo/.hg/00changelog.i
  /notarepo/.hg/requires
  /remote-with-names/.hg/bookmarks
  /remote-with-names/.hg/bookmarks.current
  /remote-with-names/.hg/cache/branch2-served
  /remote-with-names/.hg/cache/hgtagsfnodes1
  /remote-with-names/.hg/cache/tags2-served
  /remote-with-names/.hg/dirstate
  /remote-with-names/.hg/localtags
  /remote-with-names/.hg/requires
  /remote-with-names/.hg/store/00changelog.i
  /remote-with-names/.hg/store/00manifest.i
  /remote-with-names/.hg/store/data/%7E2ehgtags.i (no-py37 !)
  /remote-with-names/.hg/store/data/foo.i
  /remote-with-names/.hg/store/data/~2ehgtags.i (py37 !)
  /remote/.hg/bookmarks
  /remote/.hg/bookmarks.current
  /remote/.hg/cache/branch2-base
  /remote/.hg/cache/branch2-immutable
  /remote/.hg/cache/branch2-served
  /remote/.hg/cache/hgtagsfnodes1
  /remote/.hg/cache/rbc-names-v1
  /remote/.hg/cache/tags2-served
  /remote/.hg/dirstate
  /remote/.hg/localtags
  /remote/.hg/requires
  /remote/.hg/store/00changelog.i
  /remote/.hg/store/00manifest.i
  /remote/.hg/store/data/%7E2edotfile%20with%20spaces.i (no-py37 !)
  /remote/.hg/store/data/%7E2ehgtags.i (no-py37 !)
  /remote/.hg/store/data/bar.i
  /remote/.hg/store/data/quux.i
  /remote/.hg/store/data/~2edotfile%20with%20spaces.i (py37 !)
  /remote/.hg/store/data/~2ehgtags.i (py37 !)
  /remotempty/.hg/bookmarks
  /remotempty/.hg/bookmarks.current
  /remotempty/.hg/dirstate
  /remotempty/.hg/requires
  /remotempty/.hg/store/00changelog.i
  /remotempty/.hg/store/00manifest.i
  /sub/.hg/bookmarks
  /sub/.hg/bookmarks.current
  /sub/.hg/cache/hgtagsfnodes1
  /sub/.hg/dirstate
  /sub/.hg/requires
  /sub/.hg/store/00changelog.i
  /sub/.hg/store/00manifest.i
  /sub/.hg/store/data/%7E2ehgtags.i (no-py37 !)
  /sub/.hg/store/data/test.i
  /sub/.hg/store/data/~2ehgtags.i (py37 !)