revset: add optional offset argument to limit() predicate It's common for GUI or web frontend to fetch chunk of revisions per batch size. Previously it was possible only if revisions were sorted by revision number. $ hg log -r 'limit({revspec} & :{last_known}, 101)' So this patch introduces a general way to retrieve chunk of revisions after skipping offset revisions. $ hg log -r 'limit({revspec}, 100, {last_count})' This is a dumb implementation. We can optimize it for baseset and spanset later.

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.

localrepo: restore dirstate to one before rollbacking if not parent-gone 'localrepository.rollback()' explicilty restores dirstate, only if at least one of current parents of the working directory is removed at rollbacking (a.k.a "parent-gone"). After DirstateTransactionPlan, 'dirstate.write()' will cause marking '.hg/dirstate' as a file to be restored at rollbacking. https://mercurial.selenic.com/wiki/DirstateTransactionPlan Then, 'transaction.rollback()' restores '.hg/dirstate' regardless of parents of the working directory at that time, and this causes unexpected dirstate changes if not "parent-gone" (e.g. "hg update" to another branch after "hg commit" or so, then "hg rollback"). To avoid such situation, this patch restores dirstate to one before rollbacking if not "parent-gone". before: b1. restore dirstate explicitly, if "parent-gone" after: a1. save dirstate before actual rollbacking via dirstateguard a2. restore dirstate via 'transaction.rollback()' a3. if "parent-gone" - discard backup (a1) - restore dirstate from 'undo.dirstate' a4. otherwise, restore dirstate from backup (a1) Even though restoring dirstate at (a3) after (a2) seems redundant, this patch keeps this existing code path, because: - it isn't ensured that 'dirstate.write()' was invoked at least once while transaction running If not, '.hg/dirstate' isn't restored at (a2). In addition to it, rude 3rd party extension invoking 'dirstate.write()' without 'repo' while transaction running (see subsequent patches for detail) may break consistency of a file backup-ed by transaction. - this patch mainly focuses on changes for DirstateTransactionPlan Restoring dirstate at (a3) itself should be cheaper enough than rollbacking itself. Redundancy will be removed in next step. Newly added test is almost meaningless at this point. It will be used to detect regression while implementing delayed dirstate write out.

parsers: make pack_dirstate take now in integer for consistency On recent OS, 'stat.st_mtime' has a double precision floating point value to represent nano seconds, but it is not wide enough for actual file timestamp: nowadays, only 52 - 32 = 20 bit width is available for decimal places in sec. Therefore, casting it to 'int' may cause unexpected result. See also changeset 13272104bb07 fixing issue4836 for detail. For example, changed file A may be treated as "clean" unexpectedly in steps below. "rounded now" is the value gotten by rounding via 'int(st.st_mtime)' or so. ---------------------+--------------------+------------------------ "now" | | timestamp of A (time_t) float rounded time_t| action | FS dirstate ------ ------- ------+--------------------+-------- --------------- N+.nnn N N | | --- --- | update file A | N | dirstate.normal(A) | N N+.999 N+1 N | | | dirstate.write() | N (*1) | : | | change file A | N | : | N+1.00 N+1 N+1 | | | "hg status" (*2) | N N ------ ------- ------+--------------------+-------- --------------- Timestamp N of A in dirstate isn't dropped at (*1), because "rounded now" is N+1 at that time, even if 'st_mtime' in 'time_t' is still N. Then, file A is unexpectedly treated as "clean" at (*2) in this case. For consistent handling of 'stat.st_mtime', this patch makes 'pack_dirstate()' take 'now' argument not in floating point but in integer. This patch makes 'PyArg_ParseTuple()' in 'pack_dirstate()' use format 'i' (= checking type mismatch or overflow), even though it is ensured that 'now' is in the range of 32bit signed integer by masking with '_rangemask' (= 0x7fffffff) on caller side. It should be cheaper enough than packing itself, and useful to detect that legacy code invokes 'pack_dirstate()' with 'now' in floating point value.

destupdate: include the 'check' logic After moving logic from 'merge.update' into 'destutil.destupdate', we are now moving logic from 'command.update' in 'destutil.destupdate'. This will make the function actually useful in predicting (and altering) the update behavior.