caches: invalidate store caches when lock is taken
The fncache was not being properly invalidated each time the lock was taken, so
in theory it could contain old data from prior to the caller having the lock.
This changes it to be invalidated as soon as the lock is taken (same as all our
other caches).
$ "$TESTDIR/hghave" execbit || exit 80
$ hg init
$ echo a > a
$ hg ci -Am'not executable'
adding a
$ chmod +x a
$ hg ci -m'executable'
$ hg id
79abf14474dc tip
Make sure we notice the change of mode if the cached size == -1:
$ hg rm a
$ hg revert -r 0 a
$ hg debugstate
n 0 -1 unset a
$ hg status
M a
$ hg up 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg id
d69afc33ff8a
$ test -x a && echo executable -- bad || echo not executable -- good
not executable -- good