tests/test-status-inprocess.py.out

dirstate: make writing in-memory changes aware of transaction activity

This patch delays writing in-memory changes out, if transaction is
running.

'_getfsnow()' is defined as a function, to hook it easily for
ambiguous timestamp tests (see also fakedirstatewritetime.py)

'if tr:' code path in this patch is still disabled at this revision,
because there is no client invoking 'dirstate.write()' with repo
object.

BTW, this patch changes 'dirstate.invalidate()' semantics around
'dirstate.write()' in a transaction scope:

  before:
    with repo.transaction():
        dirstate.CHANGE('A')
        dirstate.write() # change for A is written out here
        dirstate.CHANGE('B')
        dirstate.invalidate() # discards only change for B

  after:
    with repo.transaction():
        dirstate.CHANGE('A')
        dirstate.write() # change for A is still kept in memory
        dirstate.CHANGE('B')
        dirstate.invalidate() # discards changes for A and B

Fortunately, there is no code path expecting the former, at least, in
Mercurial itself, because 'dirstateguard' was introduced to remove
such 'dirstate.invalidate()'.

% creating repo
% add and commit
C test.py
% change
M test.py