view tests/test-sidedata-exchange.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.

===========================
Tests for sidedata exchange
===========================

Check simple exchange behavior
==============================

Pusher and pushed have sidedata enabled
---------------------------------------

  $ hg init sidedata-source --config format.exp-use-side-data=yes
  $ cat << EOF >> sidedata-source/.hg/hgrc
  > [extensions]
  > testsidedata=$TESTDIR/testlib/ext-sidedata-5.py
  > EOF
  $ hg init sidedata-target --config format.exp-use-side-data=yes
  $ cat << EOF >> sidedata-target/.hg/hgrc
  > [extensions]
  > testsidedata=$TESTDIR/testlib/ext-sidedata-5.py
  > EOF
  $ cd sidedata-source
  $ echo a > a
  $ echo b > b
  $ echo c > c
  $ hg commit -Am "initial"
  adding a
  adding b
  adding c
  $ echo aa > a
  $ hg commit -m "other"
  $ hg push -r . ../sidedata-target
  pushing to ../sidedata-target
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 4 changes to 3 files
  $ hg -R ../sidedata-target debugsidedata -c 0
  2 sidedata entries
   entry-0001 size 4
   entry-0002 size 32
  $ hg -R ../sidedata-target debugsidedata -c 1 -v
  2 sidedata entries
   entry-0001 size 4
    '\x00\x00\x00:'
   entry-0002 size 32
    '\xa3\xee4v\x99\x85$\x9f\x1f\x8dKe\x0f\xc3\x9d-\xc9\xb5%[\x15=h\xe9\xf2O\xb5\xd9\x1f*\xff\xe5'
  $ hg -R ../sidedata-target debugsidedata -m 0
  2 sidedata entries
   entry-0001 size 4
   entry-0002 size 32
  $ hg -R ../sidedata-target debugsidedata -m 1 -v
  2 sidedata entries
   entry-0001 size 4
    '\x00\x00\x00\x81'
   entry-0002 size 32
    '-bL\xc5\xa4uu"#\xac\x1b`,\xc0\xbc\x9d\xf5\xac\xf0\x1d\x89)2\xf8N\xb1\x14m\xce\xd7\xbc\xae'
  $ hg -R ../sidedata-target debugsidedata a 0
  2 sidedata entries
   entry-0001 size 4
   entry-0002 size 32
  $ hg -R ../sidedata-target debugsidedata a 1 -v
  2 sidedata entries
   entry-0001 size 4
    '\x00\x00\x00\x03'
   entry-0002 size 32
    '\xd9\xcd\x81UvL5C\xf1\x0f\xad\x8aH\rt17Fo\x8dU!<\x8e\xae\xfc\xd1/\x06\xd4:\x80'
  $ cd ..

Puller and pulled have sidedata enabled
---------------------------------------

  $ rm -rf sidedata-source sidedata-target
  $ hg init sidedata-source --config format.exp-use-side-data=yes
  $ cat << EOF >> sidedata-source/.hg/hgrc
  > [extensions]
  > testsidedata=$TESTDIR/testlib/ext-sidedata-5.py
  > EOF
  $ hg init sidedata-target --config format.exp-use-side-data=yes
  $ cat << EOF >> sidedata-target/.hg/hgrc
  > [extensions]
  > testsidedata=$TESTDIR/testlib/ext-sidedata-5.py
  > EOF
  $ cd sidedata-source
  $ echo a > a
  $ echo b > b
  $ echo c > c
  $ hg commit -Am "initial"
  adding a
  adding b
  adding c
  $ echo aa > a
  $ hg commit -m "other"
  $ hg pull -R ../sidedata-target ../sidedata-source
  pulling from ../sidedata-source
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 4 changes to 3 files
  new changesets 05da661850d7:7ec8b4049447
  (run 'hg update' to get a working copy)
  $ hg -R ../sidedata-target debugsidedata -c 0
  2 sidedata entries
   entry-0001 size 4
   entry-0002 size 32
  $ hg -R ../sidedata-target debugsidedata -c 1 -v
  2 sidedata entries
   entry-0001 size 4
    '\x00\x00\x00:'
   entry-0002 size 32
    '\xa3\xee4v\x99\x85$\x9f\x1f\x8dKe\x0f\xc3\x9d-\xc9\xb5%[\x15=h\xe9\xf2O\xb5\xd9\x1f*\xff\xe5'
  $ hg -R ../sidedata-target debugsidedata -m 0
  2 sidedata entries
   entry-0001 size 4
   entry-0002 size 32
  $ hg -R ../sidedata-target debugsidedata -m 1 -v
  2 sidedata entries
   entry-0001 size 4
    '\x00\x00\x00\x81'
   entry-0002 size 32
    '-bL\xc5\xa4uu"#\xac\x1b`,\xc0\xbc\x9d\xf5\xac\xf0\x1d\x89)2\xf8N\xb1\x14m\xce\xd7\xbc\xae'
  $ hg -R ../sidedata-target debugsidedata a 0
  2 sidedata entries
   entry-0001 size 4
   entry-0002 size 32
  $ hg -R ../sidedata-target debugsidedata a 1 -v
  2 sidedata entries
   entry-0001 size 4
    '\x00\x00\x00\x03'
   entry-0002 size 32
    '\xd9\xcd\x81UvL5C\xf1\x0f\xad\x8aH\rt17Fo\x8dU!<\x8e\xae\xfc\xd1/\x06\xd4:\x80'
  $ cd ..

Now on to asymmetric configs.

Pusher has sidedata enabled, pushed does not
--------------------------------------------

  $ rm -rf sidedata-source sidedata-target
  $ hg init sidedata-source --config format.exp-use-side-data=yes
  $ cat << EOF >> sidedata-source/.hg/hgrc
  > [extensions]
  > testsidedata=$TESTDIR/testlib/ext-sidedata-5.py
  > EOF
  $ hg init sidedata-target --config format.exp-use-side-data=no
  $ cd sidedata-source
  $ echo a > a
  $ echo b > b
  $ echo c > c
  $ hg commit -Am "initial"
  adding a
  adding b
  adding c
  $ echo aa > a
  $ hg commit -m "other"
  $ hg push -r . ../sidedata-target --traceback
  pushing to ../sidedata-target
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 4 changes to 3 files
  $ hg -R ../sidedata-target log -G
  o  changeset:   1:7ec8b4049447
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     other
  |
  o  changeset:   0:05da661850d7
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     initial
  

  $ hg -R ../sidedata-target debugsidedata -c 0
  $ hg -R ../sidedata-target debugsidedata -c 1 -v
  $ hg -R ../sidedata-target debugsidedata -m 0
  $ hg -R ../sidedata-target debugsidedata -m 1 -v
  $ hg -R ../sidedata-target debugsidedata a 0
  $ hg -R ../sidedata-target debugsidedata a 1 -v
  $ cd ..

Pulled has sidedata enabled, puller does not
--------------------------------------------

  $ rm -rf sidedata-source sidedata-target
  $ hg init sidedata-source --config format.exp-use-side-data=yes
  $ cat << EOF >> sidedata-source/.hg/hgrc
  > [extensions]
  > testsidedata=$TESTDIR/testlib/ext-sidedata-5.py
  > EOF
  $ hg init sidedata-target --config format.exp-use-side-data=no
  $ cd sidedata-source
  $ echo a > a
  $ echo b > b
  $ echo c > c
  $ hg commit -Am "initial"
  adding a
  adding b
  adding c
  $ echo aa > a
  $ hg commit -m "other"
  $ hg pull -R ../sidedata-target ../sidedata-source
  pulling from ../sidedata-source
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 4 changes to 3 files
  new changesets 05da661850d7:7ec8b4049447
  (run 'hg update' to get a working copy)
  $ hg -R ../sidedata-target log -G
  o  changeset:   1:7ec8b4049447
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     other
  |
  o  changeset:   0:05da661850d7
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     initial
  

  $ hg -R ../sidedata-target debugsidedata -c 0
  $ hg -R ../sidedata-target debugsidedata -c 1 -v
  $ hg -R ../sidedata-target debugsidedata -m 0
  $ hg -R ../sidedata-target debugsidedata -m 1 -v
  $ hg -R ../sidedata-target debugsidedata a 0
  $ hg -R ../sidedata-target debugsidedata a 1 -v
  $ cd ..


Check sidedata exchange with on-the-fly generation and removal
==============================================================

(Push) Target has strict superset of the source
-----------------------------------------------

  $ hg init source-repo --config format.exp-use-side-data=yes
  $ hg init target-repo --config format.exp-use-side-data=yes
  $ cat << EOF >> target-repo/.hg/hgrc
  > [extensions]
  > testsidedata=$TESTDIR/testlib/ext-sidedata.py
  > EOF
  $ cd source-repo
  $ echo aaa > a
  $ hg add a
  $ hg commit -m a
  $ echo aaa > b
  $ hg add b
  $ hg commit -m b
  $ echo xxx >> a
  $ hg commit -m aa

No sidedata is generated in the source
  $ hg debugsidedata -c 0

Check that sidedata capabilities are advertised
  $ hg debugcapabilities ../target-repo | grep sidedata
    exp-wanted-sidedata=1,2

We expect the client to abort the push since it's not capable of generating
what the server is asking
  $ hg push -r . ../target-repo
  pushing to ../target-repo
  abort: cannot push: required sidedata category not supported by this client: '1'
  [255]

Add the required capabilities
  $ cat << EOF >> .hg/hgrc
  > [extensions]
  > testsidedata2=$TESTDIR/testlib/ext-sidedata-2.py
  > EOF

We expect the target to have sidedata that was generated by the source on push
  $ hg push -r . ../target-repo
  pushing to ../target-repo
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 2 files
  $ cd ../target-repo
  $ hg debugsidedata -c 0
  2 sidedata entries
   entry-0001 size 4
   entry-0002 size 32
  $ hg debugsidedata -c 1 -v
  2 sidedata entries
   entry-0001 size 4
    '\x00\x00\x006'
   entry-0002 size 32
    '\x98\t\xf9\xc4v\xf0\xc5P\x90\xf7wRf\xe8\xe27e\xfc\xc1\x93\xa4\x96\xd0\x1d\x97\xaaG\x1d\xd7t\xfa\xde'
  $ hg debugsidedata -m 2
  2 sidedata entries
   entry-0001 size 4
   entry-0002 size 32
  $ hg debugsidedata a 1
  2 sidedata entries
   entry-0001 size 4
   entry-0002 size 32
  $ cd ..

(Push) Difference is not subset/superset
----------------------------------------

Source has one in common, one missing and one more sidedata category with the
target.

  $ rm -rf source-repo target-repo
  $ hg init source-repo --config format.exp-use-side-data=yes
  $ cat << EOF >> source-repo/.hg/hgrc
  > [extensions]
  > testsidedata3=$TESTDIR/testlib/ext-sidedata-3.py
  > EOF
  $ hg init target-repo --config format.exp-use-side-data=yes
  $ cat << EOF >> target-repo/.hg/hgrc
  > [extensions]
  > testsidedata4=$TESTDIR/testlib/ext-sidedata-4.py
  > EOF
  $ cd source-repo
  $ echo aaa > a
  $ hg add a
  $ hg commit -m a
  $ echo aaa > b
  $ hg add b
  $ hg commit -m b
  $ echo xxx >> a
  $ hg commit -m aa

Check that sidedata capabilities are advertised
  $ hg debugcapabilities . | grep sidedata
    exp-wanted-sidedata=1,2
  $ hg debugcapabilities ../target-repo | grep sidedata
    exp-wanted-sidedata=2,3

Sidedata is generated in the source, but only the right categories (entry-0001 and entry-0002)
  $ hg debugsidedata -c 0
  2 sidedata entries
   entry-0001 size 4
   entry-0002 size 32
  $ hg debugsidedata -c 1 -v
  2 sidedata entries
   entry-0001 size 4
    '\x00\x00\x006'
   entry-0002 size 32
    '\x98\t\xf9\xc4v\xf0\xc5P\x90\xf7wRf\xe8\xe27e\xfc\xc1\x93\xa4\x96\xd0\x1d\x97\xaaG\x1d\xd7t\xfa\xde'
  $ hg debugsidedata -m 2
  2 sidedata entries
   entry-0001 size 4
   entry-0002 size 32
  $ hg debugsidedata a 1
  2 sidedata entries
   entry-0001 size 4
   entry-0002 size 32


We expect the target to have sidedata that was generated by the source on push,
and also removed the sidedata categories that are not supported by the target.
Namely, we expect entry-0002 (only exchanged) and entry-0003 (generated),
but not entry-0001.

  $ hg push -r . ../target-repo --traceback
  pushing to ../target-repo
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 2 files
  $ cd ../target-repo
  $ hg log -G
  o  changeset:   2:40f977031323
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     aa
  |
  o  changeset:   1:2707720c6597
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     b
  |
  o  changeset:   0:7049e48789d7
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     a
  
  $ hg debugsidedata -c 0
  2 sidedata entries
   entry-0002 size 32
   entry-0003 size 48
  $ hg debugsidedata -c 1 -v
  2 sidedata entries
   entry-0002 size 32
    '\x98\t\xf9\xc4v\xf0\xc5P\x90\xf7wRf\xe8\xe27e\xfc\xc1\x93\xa4\x96\xd0\x1d\x97\xaaG\x1d\xd7t\xfa\xde'
   entry-0003 size 48
    '\x87\xcf\xdfI/\xb5\xed\xeaC\xc1\xf0S\xf3X\x1c\xcc\x00m\xee\xe6#\xc1\xe3\xcaB8Fk\x82e\xfc\xc01\xf6\xb7\xb9\xb3([\xf6D\xa6\xcf\x9b\xea\x11{\x08'
  $ hg debugsidedata -m 2
  2 sidedata entries
   entry-0002 size 32
   entry-0003 size 48
  $ hg debugsidedata a 1
  2 sidedata entries
   entry-0002 size 32
   entry-0003 size 48
  $ cd ..

(Pull) Target has strict superset of the source
-----------------------------------------------

  $ rm -rf source-repo target-repo
  $ hg init source-repo --config format.exp-use-side-data=yes
  $ hg init target-repo --config format.exp-use-side-data=yes
  $ cat << EOF >> target-repo/.hg/hgrc
  > [extensions]
  > testsidedata=$TESTDIR/testlib/ext-sidedata.py
  > EOF
  $ cd source-repo
  $ echo aaa > a
  $ hg add a
  $ hg commit -m a
  $ echo aaa > b
  $ hg add b
  $ hg commit -m b
  $ echo xxx >> a
  $ hg commit -m aa

No sidedata is generated in the source
  $ hg debugsidedata -c 0

Check that sidedata capabilities are advertised
  $ hg debugcapabilities ../target-repo | grep sidedata
    exp-wanted-sidedata=1,2

  $ cd ../target-repo

Add the required capabilities
  $ cat << EOF >> .hg/hgrc
  > [extensions]
  > testsidedata2=$TESTDIR/testlib/ext-sidedata-2.py
  > EOF

We expect the target to have sidedata that it generated on-the-fly during pull
  $ hg pull -r . ../source-repo  --traceback
  pulling from ../source-repo
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 2 files
  new changesets 7049e48789d7:40f977031323
  (run 'hg update' to get a working copy)
  $ hg debugsidedata -c 0 --traceback
  2 sidedata entries
   entry-0001 size 4
   entry-0002 size 32
  $ hg debugsidedata -c 1 -v --traceback
  2 sidedata entries
   entry-0001 size 4
    '\x00\x00\x006'
   entry-0002 size 32
    '\x98\t\xf9\xc4v\xf0\xc5P\x90\xf7wRf\xe8\xe27e\xfc\xc1\x93\xa4\x96\xd0\x1d\x97\xaaG\x1d\xd7t\xfa\xde'
  $ hg debugsidedata -m 2
  2 sidedata entries
   entry-0001 size 4
   entry-0002 size 32
  $ hg debugsidedata a 1
  2 sidedata entries
   entry-0001 size 4
   entry-0002 size 32
  $ cd ..