view CONTRIBUTING @ 50393:f95ab2c53303

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.

Our full contribution guidelines are in our wiki, please see:

https://www.mercurial-scm.org/wiki/ContributingChanges

If you just want a checklist to follow, you can go straight to

https://www.mercurial-scm.org/wiki/ContributingChanges#Submission_checklist

If you can't run the entire testsuite for some reason (it can be
difficult on Windows), please at least run `contrib/check-code.py` on
any files you've modified and run `python contrib/check-commit` on any
commits you've made (for example, `python contrib/check-commit
273ce12ad8f1` will report some style violations on a very old commit).