view mercurial/utils/hashutil.py @ 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.

import hashlib

try:
    from ..thirdparty import sha1dc  # pytype: disable=import-error

    sha1 = sha1dc.sha1
except (ImportError, AttributeError):
    sha1 = hashlib.sha1