tests/test-issue2137.t

localrepo: don't refresh filecache entries that aren't in __dict__

We call invalidate to remove properties from __dict__ because they're
possibly outdated and we'd like to check for a new version. Next time
the property is accessed the filecache mechanism checks the current stat
info with the one recorded at the last time the property was read, if
they're different it recreates the property.

Previously we refreshed the stat info on all properties in the filecache
when the lock is released, including properties that are missing from
__dict__. This is a problem because:

  l = repo.lock()
  repo.P          # stat info S for P is recorded in _filecache
  <changes are made to repo.P indirectly, e.g. underlying file is replaced>
                  # P's new stat info = S'
  l.release()     # filecache refreshes, records S' as P's stat info

At this point our filecache contains P with stat info S', but P's
version is from S, which is outdated.

The above happens during _rollback and strip. Currently we're wiping the
filecache and forcing everything to reload from scratch which works but
isn't the right solution.

http://mercurial.selenic.com/bts/issue2137

Setup:

create a little extension that has 3 side-effects:
1) ensure changelog data is not inlined
2) make revlog to use lazyparser
3) test that repo.lookup() works
1 and 2 are preconditions for the bug; 3 is the bug.

  $ cat > commitwrapper.py <<EOF
  > from mercurial import extensions, node, revlog
  > 
  > def reposetup(ui, repo):
  >     class wraprepo(repo.__class__):
  >         def commit(self, *args, **kwargs):
  >             result = super(wraprepo, self).commit(*args, **kwargs)
  >             tip1 = node.short(repo.changelog.tip())
  >             tip2 = node.short(repo.lookup(tip1))
  >             assert tip1 == tip2
  >             ui.write('new tip: %s\n' % tip1)
  >             return result
  >     repo.__class__ = wraprepo
  > 
  > def extsetup(ui):
  >     revlog._maxinline = 8             # split out 00changelog.d early
  >     revlog._prereadsize = 8           # use revlog.lazyparser
  > EOF

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > commitwrapper = `pwd`/commitwrapper.py
  > EOF

  $ hg init repo1
  $ cd repo1
  $ echo a > a
  $ hg commit -A -m'add a with a long commit message to make the changelog a bit bigger'
  adding a
  new tip: 553596fad57b

Test that new changesets are visible to repo.lookup():

  $ echo a >> a
  $ hg commit -m'one more commit to demonstrate the bug'
  new tip: 799ae3599e0e

  $ hg tip
  changeset:   1:799ae3599e0e
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     one more commit to demonstrate the bug
  

  $ cd ..