upgrade: directly use the upgrade action constant This make the code simpler and will make it simpler to add more case in the future. Differential Revision: https://phab.mercurial-scm.org/D9467

upgrade: rename UPGRADE_FILELOG to UPGRADE_FILELOGS They are multiple filelog to upgrade, so this seems more accurate. Differential Revision: https://phab.mercurial-scm.org/D9466

bisect: add `-G` to an `hg log` command in a test This helps readers see what shape of DAG to expect Differential Revision: https://phab.mercurial-scm.org/D9373

bisect: refactor to work on a list of revspecs This will allow adding a `--rev` flag that can be passed more than once. Differential Revision: https://phab.mercurial-scm.org/D9372

copies: simplify the call to _merge_copies_dict Let's get the argument into the right order, then call the function once. Differential Revision: https://phab.mercurial-scm.org/D9417

copies: fast path no-op merge If the two sides of the merge are the same (they come an unaltered common ancestors) we don't need any merging. Differential Revision: https://phab.mercurial-scm.org/D9415

copies-rust: encapsulate internal sets on `changes` The goal is to eventually stop creating the underlying set. So we need to encapsulate the call first. Differential Revision: https://phab.mercurial-scm.org/D9306

copies-rust: pre-indent some code to clarify the next patch The next patch will need this new indentation, having it done explicitly beforehand makes that next patch clearer. Differential Revision: https://phab.mercurial-scm.org/D9305