view tests/test-committer.t @ 32558:aa91085cadf3

transaction: delete callbacks after use

Before this change, localrepository instances that performed multiple
transactions would leak transaction objects. This could occur when
running `hg convert`. When running `hg convert`, the leak would be
~90 MB per 10,000 changesets as measured with the Mercurial repo itself.

The leak I tracked down involved the "validate" closure from
localrepository.transaction(). It appeared to be keeping a
reference to the original transaction via __closure__. __del__
semantics and a circular reference involving the repo object
may have also come into play.

Attempting to refactor the "validate" closure proved to be
difficult because the "tr" reference in that closure may
reference an object that isn't created until transaction.__init__
is called. And the "validate" closure is passed as an argument to
transaction.__init__. Plus there is a giant warning comment in
"validate" about how hacky it is. I did not want to venture into
the dragon den.

Anyway, we've had problems with transactions causing leaks before.
The solution then (14e683d6b273) is the same as the solution in this
patch: drop references to callbacks after they are called. This
not only breaks cycles in core Mercurial but can help break cycles
in extensions that accidentally introduce them.

While I only tracked down a leak due to self.validator, since this is
the 2nd time I've tracked down leaks due to transaction callbacks I
figure enough is enough and we should prevent the class of leak from
occurring regardless of the variable. That's why all callback variables
are now nuked.

  $ unset HGUSER
  $ EMAIL="My Name <[e-mail]>"
  $ export EMAIL

  $ hg init test
  $ cd test
  $ touch asdf
  $ hg add asdf
  $ hg commit -m commit-1
  $ hg tip
  changeset:   0:53f268a58230
  tag:         tip
  user:        My Name <[e-mail]>
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     commit-1
  

  $ unset EMAIL
  $ echo 1234 > asdf
  $ hg commit -u "[e-mail]" -m commit-1
  $ hg tip
  changeset:   1:3871b2a9e9bf
  tag:         tip
  user:        [e-mail]
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     commit-1
  
  $ echo "[ui]" >> .hg/hgrc
  $ echo "username = foobar <[e-mail]>" >> .hg/hgrc
  $ echo 12 > asdf
  $ hg commit -m commit-1
  $ hg tip
  changeset:   2:8eeac6695c1c
  tag:         tip
  user:        foobar <[e-mail]>
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     commit-1
  
  $ echo 1 > asdf
  $ hg commit -u "[e-mail]" -m commit-1
  $ hg tip
  changeset:   3:957606a725e4
  tag:         tip
  user:        [e-mail]
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     commit-1
  
  $ echo 123 > asdf
  $ echo "[ui]" > .hg/hgrc
  $ echo "username = " >> .hg/hgrc
  $ hg commit -m commit-1
  abort: no username supplied
  (use 'hg config --edit' to set your username)
  [255]

# test alternate config var

  $ echo 1234 > asdf
  $ echo "[ui]" > .hg/hgrc
  $ echo "user = Foo Bar II <[e-mail]>" >> .hg/hgrc
  $ hg commit -m commit-1
  $ hg tip
  changeset:   4:6f24bfb4c617
  tag:         tip
  user:        Foo Bar II <[e-mail]>
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     commit-1
  
# test prompt username

  $ cat > .hg/hgrc <<EOF
  > [ui]
  > askusername = True
  > EOF

  $ echo 12345 > asdf
  $ hg commit --config ui.interactive=False -m ask
  enter a commit username: 
  no username found, using '[^']*' instead (re)
  $ hg rollback -q

  $ hg commit --config ui.interactive=True -m ask <<EOF
  > Asked User <[e-mail]>
  > EOF
  enter a commit username: Asked User <[e-mail]>
  $ hg tip
  changeset:   5:84c91d963b70
  tag:         tip
  user:        Asked User <[e-mail]>
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     ask
  

# test no .hg/hgrc (uses generated non-interactive username)

  $ echo space > asdf
  $ rm .hg/hgrc
  $ hg commit -m commit-1 2>&1
  no username found, using '[^']*' instead (re)

  $ echo space2 > asdf
  $ hg commit -u ' ' -m commit-1
  transaction abort!
  rollback completed
  abort: empty username!
  [255]

# don't add tests here, previous test is unstable

  $ cd ..