revset: port limit() to support keyword arguments The next patch will introduce the third 'offset' argument. This allows us to specify 'offset' without 'n' argument.

revset: eliminate temporary reference to subset in limit() and last()

dirstate: read from pending file under HG_PENDING mode if it exists True/False value of '_pendingmode' means whether 'dirstate.pending' is used to initialize own '_map' and so on. When it is None, neither 'dirstate' nor 'dirstate.pending' is read in yet. This is used to keep consistent view between '_pl()' and '_read()'. Once '_pendingmode' is determined by reading one of 'dirstate' or 'dirstate.pending' in, '_pendingmode' is kept even if 'invalidate()' is invoked. This should be reasonable, because: - effective 'invalidate()' invocation should occur only in wlock scope, and - wlock can't be gotten under HG_PENDING mode '_trypending()' is defined as a normal function to factor similar code path (in bookmarks and phases) out in the future easily.

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()'.

dirstate: make functions for backup aware of transaction activity Some comments in this patch assume that subsequent patch changes 'dirstate.write()' like as below: def write(self, repo): if not self._dirty: return tr = repo.currenttransaction() if tr: tr.addfilegenerator('dirstate', (self._filename,), self._writedirstate, location='plain') return # omit actual writing out st = self._opener('dirstate', "w", atomictemp=True) self._writedirstate(st) This patch makes '_savebackup()' write in-memory changes out, and it causes clearing 'self._dirty'. If dirstate isn't changed after '_savebackup()', subsequent 'dirstate.write()' never invokes 'tr.addfilegenerator()' because 'not self._dirty' is true. Then, 'tr.writepending()' unintentionally returns False, if there is no other (e.g. changelog) changes pending, even though dirstate changes are already written out at '_savebackup()'. To avoid such situation, this patch makes '_savebackup()' explicitly invoke 'tr.addfilegenerator()', if transaction is running. '_savebackup()' should get awareness of transaction before 'write()', because the former depends on the behavior of the latter before this patch.

dirstate: move code paths for backup from dirstateguard to dirstate This can centralize the logic to write in-memory changes out correctly according to transaction activity into dirstate. Passing 'repo' object to newly added functions is needed to examine current transaction activity in subsequent patches, because 'dirstate' itself doesn't have direct reference to it.