clfilter: ensure cache invalidation is done on the main unfiltered repo The proxy version will not hold any cache for now. But we have to ensure all cache operations are done on the unfiltered version.

clfilter: ensure that tag logic runs unfiltered The current tag logic is not aware of filtering. We keep the status quo, ensuring that the tag cache is computed as before: without any filtering.

clfilter: ensure `branchcache` logic runs unfiltered The current branchcache construction is not aware of filtering. We keep the status quo, ensuring that the branch cache logic is computed as before: without any filtering.

clfilter: introduce an `unfilteredmethod` decorator This decorator ensure the method in run on an unfiltered version of the repository. See follow-up commit for details. This decorator is not named `unfiltered` because it would clash with the `unfilteredmethod` on `localrepo` itself.

clfilter: introduce an "unfiltered" method on localrepo This commit is part of the changelog level filtering effort. It returns the main "unfiltered" version of a repo-like object. For localrepo this means the same localrepo object. But this method will be overwritten by the filtered versions of a repository to return the core unfiltered version of the repo. Introducing this simple method first allows later commits to prepare for the use of a filtered version of a repository. A new repo method is added because a lot of users may call it. At the end of this series of commits, about 40 calls exist in core and hgext.

clfilter: remove usage of `range` and `xrange` in scmutil.revrange For changelog level filtering to take effect it need to be used for any iteration. This changeset removes usage of `range` and `xrange` that survived the first pass.

hgweb: display diff for a changeset against any parents (issue2810) During merge of branches, it is useful to compare merge results against the two parents. This change adds this support to hgweb. To specify which parent to compare to, use rev/12300:12345 where 12300 is a parent changeset number. Two links are added to changeset web page so that one can choose which parent to compare to.

branch: add missing repo argument to checknewlabel scmutil.checknewlabel takes a repo object as its first argument. When the call to this function was added in e689b0d91546, the first argument was mistakenly set to 'None'.