obsolete: compute unstable changeset An unstable changeset is a changeset *not* obsolete but with some obsolete ancestors. The current logic to decide if a changeset is unstable is naive and very inefficient. A better solution is to compute the set of unstable changeset with a simple revset and to cache the result. But this require cache invalidation logic. Simpler version goes first.

revset: add an `obsolete` symbol This predicate matches obsolete changesets. This is a naive implementation to be improved later.

push: refuse to push obsolete changesets This is a first version. Simple but not very efficient. Note that this changeset introduce the "obsolete" word in the UI.

push: accept revset argument for --rev

check-code: recognise %= as an operator

tests: do exclude what is expected

parsers.c: remove warning: 'size' may be used uninitialized in this function Some compilers / compiler options (such as gcc 4.7) would emit warnings: mercurial/parsers.c: In function 'pack_dirstate': mercurial/parsers.c:306:18: warning: 'size' may be used uninitialized in this function [-Wmaybe-uninitialized] mercurial/parsers.c:306:12: warning: 'mode' may be used uninitialized in this function [-Wmaybe-uninitialized] It is apparently not smart enough to figure out how the 'err' arithmetics makes sure that it can't happen. 'err' is now replaced with simple checks and goto. That might also help the optimizer when it is inlining getintat().

graphlog: remove unused ASCIIDATA constant It was introduced by d9acbe7b0049, returned by asciiformat() but never read anywhere. 20140c249e63 stopped using it completely, and the graphmod.CHANGESET type is passed through all functions.

graphlog: make functions private, fix names

graphlog: remove unused get_revs() function

localrepo: use file API via vfs while ensuring repository directory As a part of migration to vfs, this patch invokes some file API indirectly via vfs, while ensuring repository directory in the constructor of "localrepository" class. New file API are added to "scmutil.abstractopener" class, because they are also used via other derived classes than "scmutil.opener". But "join()" is not yet defined other than "scmutil.opener" class, because it should not be used via other opener classes yet.

localrepo: use "vfs" intead of "opener" while ensuring repository directory As a part of migration to vfs, this patch uses "self.vfs" instead of "self.opener", while ensuring repository directory in the constructor of "localrepository" class.