phabricator: preserve the phase when amending in the Differential fields I have no idea if it's better to change scmutil.cleanupnodes() so that it has the option to either apply a specific phase (e.g. for various --secret switches) or carry over the phase of the old node. The benefit would be that the caller doesn't have to remember to do this. The con is maybe inefficiency? I wrote this up as issue5918. I'm leaving that open since Yuya flagged it as an API bug. Since most other callers already do this, it's the simplest fix. (It's not obvious that `split`, `fix` and `rebase` are doing this, but there is test coverage for `fix` and `rebase`, and experimenting with `split` shows it does the right thing.)