merge: consistently use single quotes for non-user-facing strings Because I'm getting tired of searching for both 'O' and "O".

localrepo: add a currenttransaction method This method returnx the current transaction or None: it will allow a cache writer to hook in an existing transaction.

repoview: extract actual hidden cache writing in its own function This will allow the generation of this cache within the transaction. Relying on the transaction will reduce the chance of reader seeing bad cache.

templates: fix broken "less" & "more" links in paper style (issue4460) "/search", which is an invalid command in hgweb, was mistakenly used for "[show] more [revsets]" and "[show] less [revsets]" links on search page in templates "paper" (and those which inherit paper, such as coal) before and worked fine until 6e1fbcb18a75, which made hgweb more strict about invalid commands.

push: stop independent usage of bundle2 in syncphase (issue4454) The phase-syncing code was using bundle2 if the remote supported it. It was doing so without regard to bundle2 activation on the client. Moreover, the phase push is now properly included in the unified bundle2 push, so having extra code in syncphase should be useless. If the remote is bundle2-enabled, the phases should already be synced. The buggy verification code was leading to a crash when a 3.2 client was pushing to a 3.1 server. The real bundle2 path detected that their versions were incompatible, but the syncphase code failed to, sending an incompatible bundle2 to the server. We drop the useless and buggy code as a result. The "else" clause is de-indented in the process.

dirstate: speed up repeated missing directory checks In a mozilla repo with tip at bb3ff09f52fe, hg update tip~1000 && time hg revert -nq -r tip . displays ~4:20 minutes. With tip~100, it runs in ~11 s. With revision 100000, it did not finish in 12 minutes. Revert calls dirstate.status() with a matcher that matches each file in the target revision. The main problem [1] lies in dirstate._walkexplicit(), which looks for matching deleted directories by checking whether each path is prefix of any path in the dirstate. With m files in the dirstate and n files in the target revision that are not in the dirstate, this is clearly O(m*n). Let's improve by keeping a lazily initialized set of all the directories in the dirstate, so the time becomes O(m+n). After this patch, the 4:20 minutes become 5.5 s, while for a single missing path, it slows down from 1.092 s to 1.150 s (best of 4). The >12 min case becomes 5.8 s. [1] A narrower optimization would be to make revert take the fast path for '.' and '--all'.

revert: access status fields by name rather than index For better readability.

subrepo: remove "_getstorehashcachepath" referred by no other code paths

subrepo: replace direct file APIs around "writelines" by "vfs.writelines" This patch also replaces "self._getstorehashcachepath" (building absolute path up) by "self._getstorehashcachename" (building relative path up), because "vfs.writelines" requires relative path.

vfs: add "writelines" This patch allows "writelines" to take "mode" and "notindexed" arguments, because subsequent patch for subrepo requires both.