children: support specifying revision by revset Same reason as the previous patch. Differential Revision: https://phab.mercurial-scm.org/D3085

heads: add support for specifying branches by revset Before this commit, e.g. "hg heads .^" would fail with: abort: unknown revision '.^'! Like the previous patch, I don't care about the command itself (I don't think I had ever used it before), I'm just cleaning up uses of repo[<string>]. Differential Revision: https://phab.mercurial-scm.org/D3084

perf: make perfmanifest and perfnodelookup work with revsets They were using repo[rev], which only works with a single symbol (e.g. "." or "my-bookmark"), not general revsets. Switch them to scmutil.revsingle() so they can also be used with e.g. ".^". I don't actually care about these commands, but I want to remove uses of repo[<string>]. Differential Revision: https://phab.mercurial-scm.org/D3083

context: use revsymbol() in "merge.preferancestor" code Differential Revision: https://phab.mercurial-scm.org/D3082

wireproto: use repo.lookup() for lookup command I'm trying to reduce use of repo[<string>] and this seems like an obvious place to use repo.lookup(). Differential Revision: https://phab.mercurial-scm.org/D3081

localrepo: use revsymbol in lookupbranch() too lookupbranch() takes a string that comes from the CLI, so scmutil.revsymbol() is appropriate for looking it up. Differential Revision: https://phab.mercurial-scm.org/D3080

localrepo: drop "remote" argument from lookupbranch() (API) According to `hg grep --all lookupbranch`, the "remote" argument has never been used ever since it was introduced in ca739acf1a98 (commands: add more robust support for 'hg log -b' (issue2078), 2010-04-12). Differential Revision: https://phab.mercurial-scm.org/D3079