view tests/test-dirstate-race.t @ 18316:f36375576ed5

filecache: create an entry in _filecache when __set__ is called for a missing one

Preserve the invariant that if P is a filecached property on X then
P in X.__dict__ => P in X._filecache.

Previously, it was possible for a filecached property to become out of sync
with the filesystem if it was set before getting it first, since the initial
filecacheentry was created in __get__.

Old behaviour:

  repo.prop = x
  repo.invalidate() # prop has no entry in _filecache, it's not removed
                    # from __dict__
  repo.prop         # returns x like before without checking with the
                    # filesystem

New:

  repo.prop = x     # an empty entry is created in _filecache
  repo.invalidate() # prop is removed from __dict__
  repo.prop         # recreates prop

  $ hg init
  $ echo a > a
  $ hg add a
  $ hg commit -m test

Do we ever miss a sub-second change?:

  $ for i in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20; do
  >     hg co -qC 0
  >     echo b > a
  >     hg st
  > done
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a