fncachestore: defer updating the fncache file to a single file open Defers updating the fncache file with newly added entries to the end of the transaction (on e.g. pull), doing a single open call on the fncache file, instead of opening and closing it each time a new entry is added to the store. Implemented by adding a new abstract write() function on store.basicstore and registering it as a release function on the store lock in localrepo.lock (compare with dirstate.write). store.fncachestore overrides write() from basicstore and calls a new write function on the fncache object, which writes all entries to the fncache file if it's dirty. store.fncache.add() now just marks itself as dirty if a new name is added.