exchange: add fast path for subrepo check on push
Try to check if .hgsub and .hgsubstate exist at all before looking
for them in every changeset to be pushed. The latter can be quite
expensive for large repositories and the existance check is almost free.
Differential Revision: https://phab.mercurial-scm.org/D11956
== New Features ==
== Default Format Change ==
These changes affects newly created repositories (or new clone) done with
Mercurial XXX.
== New Experimental Features ==
== Bug Fixes ==
The `--no-check` and `--no-merge` now properly overwrite the behavior from `commands.update.check`.
== Backwards Compatibility Changes ==
The remotefilelog extension now requires an appropiate excludepattern
for subrepositories.
== Internal API Changes ==
The following functions have been removed:
Miscellaneous: