localrepo: execute appropriate actions for dirstate at releasing transaction Before this patch, in-memory dirstate changes are still kept over a transaction scope boundary regardless of the result of it. For "all or nothing" policy of the transaction, in-memory dirstate changes should be: - written out at successful closing a transaction, because subsequent 'dirstate.invalidate()' can lose them - discarded at failure of a transaction, because outer 'wlock.release()' or so may write them out To discard all changes in a transaction completely, this patch also restores '.hg/dirstate' by '.hg/journal.dirstate' at failure, because 'transaction' itself does nothing for files related to '.hg/journal.*' in such case (therefore, renaming in this patch is safe enough). This is a part of preparations for "transactional dirstate". See also the wiki page below for detail about it. https://mercurial.selenic.com/wiki/DirstateTransactionPlan This patch also removes redundant 'dirstate.invalidate()' just before aborting a transaction for shelve/unshelve.

transaction: add releasefn to notify the end of a transaction scope 'releasefn' is used by subsequent patch, to do appropriate action according to the result of it at the end of a transaction scope. To ensure that 'releasefn' is invoked only once, this patch invokes it after assignment 'self.journal = None', because such assignment prevents from invoked 'transaction._abort()' again via '__del__()'. def __del__(self): if self.journal: self._abort()

filemerge: move post-merge checks into a separate function This makes the overall filemerge function easier to follow, and makes upcoming work simpler.

filemerge._xmerge: drop no longer necessary 'if r:' check Cleanup from an earlier patch to make premerge be directly called from the main filemerge function.

filemerge._idump: drop no longer necessary 'if r:' check Cleanup from an earlier patch to make premerge be directly called from the main filemerge function.

filemerge._merge: drop no longer necessary 'if r:' check Cleanup from an earlier patch to make premerge be directly called from the main filemerge function.

revset: delete _updatedefaultdest as it has no users The revset is not used anywhere anymore. We delete the function until we use (and therefore test it again).

merge: get the default update destination from the function There is no value in using the revset instead of the extracted function.

update: move default destination computation to a function We ultimately want this to be accessible through a revset, but there is too much complexity here for that to work. Especially we'll have to return more than just the destination to control the behavior (eg: bookmarks to activate, etc). To prevent cycle, a new module is created, it will receive other destination/behavior function in the future.

worker: restore old countcpus code (issue4869) This is a backout of d29859cfcfc2. The stdlib implementation of multiprocessing.cpu_count() attempts to invoke a process on BSD and Darwin platforms (at least on 2.7). Under certain conditions (such as cwd being removed) this could raise. Our old code was silently catching the exception. The old code was more robust, so restore it.