templater: add class representing a nested mappings The mappinggenerator class is necessary to fix hgweb bugs without BC. The mappinglist is for nested formatter items. They are similar, so factored out the base class. The mappinglist could be implemented by using the mappinggenerator, but we'll probably need a direct access to the raw list, so they are implemented as separate classes. Note that tovalue() isn't conforming to the spec yet in that it may return a list of dicts containing unprintable resources. This problem will be fixed later. Tests will be added by subsequent patches.

templater: add function that expands internal literal templates This will be used when rendering nested formatter items with the default template, e.g. fm.nested('parents', tmpl='{rev}:{node|formatnode}', sep=' ') ^^^^^^^^^^^^^^^^^^^^^^^ the default item template

bookmarks: use isrevsymbol() for detecting collision with existing symbol Differential Revision: https://phab.mercurial-scm.org/D3167

debugwhyunstable: add support for revsets Differential Revision: https://phab.mercurial-scm.org/D3166

convert: look up branch only among branches repo[<branch name>] can find something that's not a branch, which is not good. Differential Revision: https://phab.mercurial-scm.org/D3161

convert: remove unused/unnecessary variable "parentctx" Differential Revision: https://phab.mercurial-scm.org/D3160

wireproto: provide accessors for client capabilities For HTTP, this refactors the existing logic, including the parsing of the compression engine capability. For SSH, this adds a ssh-only capability "protocaps" and a command for informing the server on what the client supports. Since SSH is stateful, keep track of the capabilities in the server instance. Differential Revision: https://phab.mercurial-scm.org/D1944

copies: clean up _related logic The limit parameter was never actually used, since the only way the 4th case could be reached was if f1r and f2r converged. The new code makes this clear, and additionally reduces the conditional block to just 3 cases.

context: stop catching RepoLookupError from namespace.singlenode() As pointed out by Yuya, the RepoLookupError was there for catching errors from repo.branchtip(). However, since 885c0290f7d5 (localrepo: add ignoremissing parameter to branchtip, 2014-10-16), that should no longer happen. I think it should now be an error if a namespace raises a RepoLookupError, so we propagate the exception up and and make it easy to fix, rather than trying to interpret the changeid as nodeid prefix and raise a general "unknown revision '...'" error. I also don't think we should catch FilteredLookupError and LookupError from the changelog.rev() call, for the same reason as above: If a namespace returns a node that doesn't exist, we should provide a more helpful exception than "unknown revision '...'". Differential Revision: https://phab.mercurial-scm.org/D3145

histedit: simplify desthistedit Instead of sorting the revset and take the first one, take the minimum revision. Differential Revision: https://phab.mercurial-scm.org/D3137