view tests/test-obshistory.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.

This test file test the various messages when accessing obsolete
revisions.

Global setup
============

  $ . $TESTDIR/testlib/obsmarker-common.sh
  $ cat >> $HGRCPATH <<EOF
  > [ui]
  > interactive = true
  > [phases]
  > publish=False
  > [experimental]
  > evolution.createmarkers = yes
  > evolution.effect-flags = yes
  > EOF

Test output on amended commit
=============================

Test setup
----------

  $ hg init $TESTTMP/local-amend
  $ cd $TESTTMP/local-amend
  $ mkcommit ROOT
  $ mkcommit A0
  $ echo 42 >> A0
  $ hg commit --amend -m "A1
  > 
  > Better commit message"
  $ hg log --hidden -G
  @  changeset:   2:4ae3a4151de9
  |  tag:         tip
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A1
  |
  | x  changeset:   1:471f378eab4c
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    rewritten using amend as 2:4ae3a4151de9
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
Actual test
-----------
  $ hg update 471f378eab4c
  abort: hidden revision '471f378eab4c' was rewritten as: 4ae3a4151de9
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden "desc(A0)"
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 471f378eab4c
  (hidden revision '471f378eab4c' was rewritten as: 4ae3a4151de9)

Test output with pruned commit
==============================

Test setup
----------

  $ hg init $TESTTMP/local-prune
  $ cd $TESTTMP/local-prune
  $ mkcommit ROOT
  $ mkcommit A0 # 0
  $ mkcommit B0 # 1
  $ hg log --hidden -G
  @  changeset:   2:0dec01379d3b
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     B0
  |
  o  changeset:   1:471f378eab4c
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
  $ hg debugobsolete --record-parents `getid 'desc(B0)'`
  1 new obsolescence markers
  obsoleted 1 changesets

  $ hg log --hidden -G
  @  changeset:   2:0dec01379d3b
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  obsolete:    pruned
  |  summary:     B0
  |
  o  changeset:   1:471f378eab4c
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  

Actual test
-----------
  $ hg up 1
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg up 0dec01379d3b
  abort: hidden revision '0dec01379d3b' is pruned
  (use --hidden to access hidden revisions)
  [255]
  $ hg up --hidden -r 'desc(B0)'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 0dec01379d3b
  (hidden revision '0dec01379d3b' is pruned)

Test output with splitted commit
================================

Test setup
----------

  $ hg init $TESTTMP/local-split
  $ cd $TESTTMP/local-split
  $ mkcommit ROOT
  $ echo 42 >> a
  $ echo 43 >> b
  $ hg commit -A -m "A0"
  adding a
  adding b
  $ hg log --hidden -G
  @  changeset:   1:471597cad322
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
# Simulate a split
  $ hg up 0
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved

  $ echo 42 >> a
  $ hg commit -A -m "A0"
  adding a
  created new head

  $ echo 43 >> b
  $ hg commit -A -m "A0"
  adding b

  $ hg debugobsolete `getid '1'` `getid '2'` `getid '3'`
  1 new obsolescence markers
  obsoleted 1 changesets

  $ hg log --hidden -G
  @  changeset:   3:f257fde29c7a
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   2:337fec4d2edc
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  | x  changeset:   1:471597cad322
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    split as 2:337fec4d2edc, 3:f257fde29c7a
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
Actual test
-----------
  $ hg update 471597cad322
  abort: hidden revision '471597cad322' was split as: 337fec4d2edc, f257fde29c7a
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden 'min(desc(A0))'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 471597cad322
  (hidden revision '471597cad322' was split as: 337fec4d2edc, f257fde29c7a)

Test output with lots of splitted commit
========================================

Test setup
----------

  $ hg init $TESTTMP/local-lots-split
  $ cd $TESTTMP/local-lots-split
  $ mkcommit ROOT
  $ echo 42 >> a
  $ echo 43 >> b
  $ echo 44 >> c
  $ echo 45 >> d
  $ hg commit -A -m "A0"
  adding a
  adding b
  adding c
  adding d
  $ hg log --hidden -G
  @  changeset:   1:de7290d8b885
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
# Simulate a split
  $ hg up 0
  0 files updated, 0 files merged, 4 files removed, 0 files unresolved

  $ echo 42 >> a
  $ hg commit -A -m "A0"
  adding a
  created new head

  $ echo 43 >> b
  $ hg commit -A -m "A0"
  adding b

  $ echo 44 >> c
  $ hg commit -A -m "A0"
  adding c

  $ echo 45 >> d
  $ hg commit -A -m "A0"
  adding d

  $ hg debugobsolete `getid '1'` `getid '2'` `getid '3'` `getid '4'` `getid '5'`
  1 new obsolescence markers
  obsoleted 1 changesets

  $ hg log --hidden -G
  @  changeset:   5:c7f044602e9b
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   4:1ae8bc733a14
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   3:f257fde29c7a
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   2:337fec4d2edc
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  | x  changeset:   1:de7290d8b885
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    split as 2:337fec4d2edc, 3:f257fde29c7a, 4:1ae8bc733a14, 5:c7f044602e9b
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
Actual test
-----------
  $ hg update de7290d8b885
  abort: hidden revision 'de7290d8b885' was split as: 337fec4d2edc, f257fde29c7a and 2 more
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden 'min(desc(A0))'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset de7290d8b885
  (hidden revision 'de7290d8b885' was split as: 337fec4d2edc, f257fde29c7a and 2 more)

Test output with folded commit
==============================

Test setup
----------

  $ hg init $TESTTMP/local-fold
  $ cd $TESTTMP/local-fold
  $ mkcommit ROOT
  $ mkcommit A0
  $ mkcommit B0
  $ hg log --hidden -G
  @  changeset:   2:0dec01379d3b
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     B0
  |
  o  changeset:   1:471f378eab4c
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
# Simulate a fold
  $ hg up 0
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo "A0" > A0
  $ echo "B0" > B0
  $ hg add A0 B0
  $ hg commit -m "C0"
  created new head

  $ hg debugobsolete `getid 'desc(A0)'` `getid 'desc(C0)'`
  1 new obsolescence markers
  obsoleted 1 changesets
  1 new orphan changesets
  $ hg debugobsolete `getid 'desc(B0)'` `getid 'desc(C0)'`
  1 new obsolescence markers
  obsoleted 1 changesets

  $ hg log --hidden -G
  @  changeset:   3:eb5a0daa2192
  |  tag:         tip
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     C0
  |
  | x  changeset:   2:0dec01379d3b
  | |  user:        test
  | |  date:        Thu Jan 01 00:00:00 1970 +0000
  | |  obsolete:    rewritten as 3:eb5a0daa2192
  | |  summary:     B0
  | |
  | x  changeset:   1:471f378eab4c
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    rewritten as 3:eb5a0daa2192
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
 Actual test
 -----------
  $ hg update 471f378eab4c
  abort: hidden revision '471f378eab4c' was rewritten as: eb5a0daa2192
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden 'desc(A0)'
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  updated to hidden changeset 471f378eab4c
  (hidden revision '471f378eab4c' was rewritten as: eb5a0daa2192)
  $ hg update 0dec01379d3b
  abort: hidden revision '0dec01379d3b' was rewritten as: eb5a0daa2192
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden 'desc(B0)'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 0dec01379d3b
  (hidden revision '0dec01379d3b' was rewritten as: eb5a0daa2192)

Test output with divergence
===========================

Test setup
----------

  $ hg init $TESTTMP/local-divergence
  $ cd $TESTTMP/local-divergence
  $ mkcommit ROOT
  $ mkcommit A0
  $ hg commit --amend -m "A1"
  $ hg log --hidden -G
  @  changeset:   2:fdf9bde5129a
  |  tag:         tip
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A1
  |
  | x  changeset:   1:471f378eab4c
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    rewritten using amend as 2:fdf9bde5129a
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
  $ hg update --hidden 'desc(A0)'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 471f378eab4c
  (hidden revision '471f378eab4c' was rewritten as: fdf9bde5129a)
  $ hg commit --amend -m "A2"
  2 new content-divergent changesets
  $ hg log --hidden -G
  @  changeset:   3:65b757b745b9
  |  tag:         tip
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  instability: content-divergent
  |  summary:     A2
  |
  | *  changeset:   2:fdf9bde5129a
  |/   parent:      0:ea207398892e
  |    user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    instability: content-divergent
  |    summary:     A1
  |
  | x  changeset:   1:471f378eab4c
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    rewritten using amend as 2:fdf9bde5129a
  |    obsolete:    rewritten using amend as 3:65b757b745b9
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
Actual test
-----------
  $ hg update 471f378eab4c
  abort: hidden revision '471f378eab4c' has diverged
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden 'desc(A0)'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 471f378eab4c
  (hidden revision '471f378eab4c' has diverged)

Test output with amended + folded commit
========================================

Test setup
----------

  $ hg init $TESTTMP/local-amend-fold
  $ cd $TESTTMP/local-amend-fold
  $ mkcommit ROOT
  $ mkcommit A0
  $ mkcommit B0
  $ hg commit --amend -m "B1"
  $ hg log --hidden -G
  @  changeset:   3:b7ea6d14e664
  |  tag:         tip
  |  parent:      1:471f378eab4c
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     B1
  |
  | x  changeset:   2:0dec01379d3b
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    rewritten using amend as 3:b7ea6d14e664
  |    summary:     B0
  |
  o  changeset:   1:471f378eab4c
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  

# Simulate a fold
  $ hg up 0
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo "A0" > A0
  $ echo "B0" > B0
  $ hg add A0 B0
  $ hg commit -m "C0"
  created new head

  $ hg debugobsolete `getid 'desc(A0)'` `getid 'desc(C0)'`
  1 new obsolescence markers
  obsoleted 1 changesets
  1 new orphan changesets
  $ hg debugobsolete `getid 'desc(B1)'` `getid 'desc(C0)'`
  1 new obsolescence markers
  obsoleted 1 changesets

  $ hg log --hidden -G
  @  changeset:   4:eb5a0daa2192
  |  tag:         tip
  |  parent:      0:ea207398892e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     C0
  |
  | x  changeset:   3:b7ea6d14e664
  | |  parent:      1:471f378eab4c
  | |  user:        test
  | |  date:        Thu Jan 01 00:00:00 1970 +0000
  | |  obsolete:    rewritten as 4:eb5a0daa2192
  | |  summary:     B1
  | |
  | | x  changeset:   2:0dec01379d3b
  | |/   user:        test
  | |    date:        Thu Jan 01 00:00:00 1970 +0000
  | |    obsolete:    rewritten using amend as 3:b7ea6d14e664
  | |    summary:     B0
  | |
  | x  changeset:   1:471f378eab4c
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    obsolete:    rewritten as 4:eb5a0daa2192
  |    summary:     A0
  |
  o  changeset:   0:ea207398892e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     ROOT
  
 Actual test
 -----------
  $ hg update 471f378eab4c
  abort: hidden revision '471f378eab4c' was rewritten as: eb5a0daa2192
  (use --hidden to access hidden revisions)
  [255]
  $ hg update --hidden 'desc(A0)'
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  updated to hidden changeset 471f378eab4c
  (hidden revision '471f378eab4c' was rewritten as: eb5a0daa2192)
  $ hg update --hidden 0dec01379d3b
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 0dec01379d3b
  (hidden revision '0dec01379d3b' was rewritten as: eb5a0daa2192)
  $ hg update 0dec01379d3b
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg update --hidden 'desc(B0)'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved