filteredhash: split the computation of revision sets
The branch2's filteredhash combines the filtered revisions and the obsolete
ones, this will creates issue for implicit reference to heads we want to
introduce for the v3 of the branch cache format. So we isolate this logic for
alternative use.
== New Features ==
* The amend extension supports the `--currentuser` argument.
* The amend extension supports the `--close-branch` argument.
* The amend extension supports the `--secret` argument.
* The uncommit extension supports the `rewrite.update-timestamp` config option.
== New Experimental Features ==
== Bug Fixes ==
== Backwards Compatibility Changes ==
* A shell that supports `$(command)`` syntax for command substitution is now
required for running the test suite. The test runner normally uses
`sh`, so if that is a shell that doesn't support `$(command)` syntax,
you can override it by setting `$HGTEST_SHELL` or by passing it to
`run-tests.py --shell <shell>`.
* The (experimental) narrow extension's wire protocol changed. If
you're using it, you'll need to make sure to upgrade server and
client at the same time.
== Internal API Changes ==