py3: add one more passing test to whitelist caught by buildbot Thanks to Matt Harbison who fixed the remaining failures of this test. Differential Revision: https://phab.mercurial-scm.org/D4814

cleanupnodes: pass multiple predecessors to `createmarkers` directly

obsolete: allow multiple predecessors in createmarkers The logic for this change is similar to the change to `cleanupnodes` that we did earlier. Now that the rebase code is trying to record a fold, we need to actually record it in the markers. The first step is to have the markers creation API able to receive such fold data. To keep things sane, we restrict fold to on successors.

obsolete: preindent code in createmarkers This will help to make the next change clearer.

obsolete: explicitly pass relation items to effectflag computation To track folds, we are about to change the content of `rel`. To simplify this change, we update the `geteffectflag` function beforehand.

rebase: explicitly track collapses as fold A collapse is a large fold. It is now explicitly tracked (at the cleanupnodes API level).

rebase: use tuple as `replacement` keys Now that `cleanupnodes` support tuples as key, we update the rebase code to use them. No changes in the replacement tracked are introduced yet.

rebase: expand a long "one-liner" When a one-liner gets 3 lines longs, it lose its expressivity benefits. We expand it into a simple for loop. This makes future changes of the code in that area clearer.

cleanupnodes: drop special casing around prune markers (API) The `cleanupnodes` has logic to skip the creation of "prune" markers if the changeset is already obsolete. This feels strange and gets in the way of code changes to tracks folds. Now that callers no longer request such prune, we can drop this logic. In many cases, pruning through cleanupnodes should be replaced by internal phase usage.

rebase: don't try to prune obsolete changeset already in the destination With similar motivations to the previous changesets, we stop marking changeset from pruning when it is not the command intention. In this case, we still need to distinguish between the strip and the obsolete case.