strip: do now include internal changeset in the strip backup See inline comment for details.

revset: add `_internal()` predicate This predicate help core code to select internal changeset (in the internal phase).

strip: drop the assert about bundled revision This is working well, so no need for extract computation. See the previous changeset for the rationnal of still have these assert around for a short interval.

strip: explicitly compute the boundary of the backup bundle We want to make change to the set of backed up revision in a future changeset, we start with a change of the computation without any changes in the semantic to clarify later changeset. The could of costly assert are here to testify that the result is still correct. They will be removed in the next changesets, but I wanted them in this changeset to help in case someone bisect a regression to this changeset in the future.

outgoing: fix common-heads computation from `missingroots` argument When initializing a `outgoing` object, the `common set` can be defined explicitly (with the `commonheads` argument`) or implicitly (with the missingroots arguments). It turns out the logic to compute `commonheads` from `missingroots` is buggy, as it does not consider the parents of enough changesets. Previously, it only considered parents of "missingroots` items, while it need to consider all parents of missing. Here is an example: F |\ C E | | B D |/ A If we use [E] as missing-roots, the missing set is [E, F], and the common-heads are [C, D]. However you cannot only consider the parent of [E] to find them, as [C] is not a parent of [E]. This already fix the bundle generated in one test, and it would prevent many other to misbehave with future change from this series.

bundle: include required phases when saving a bundle (issue6794) We now properly computes and includes phases above secret in bundle, previously, they would be skipped, and then the code computing them would crash. Note that from this changeset, we also include the heads associated with the changegroup's "target" phase. This turned out to be necessary to ensure the movement of changeset included in the bundle, but already known locally. This explain why lines for "secret" heads appears in multiple tests.