D1499: hbisect: use a defaultdict to avoid large allocations for a large changelogs

[yuja (Yuya Nishihara)]

yuja added a comment.


  Queued, thanks. I don't have any number, but this seems good for a common
  scenario in which a small part of a large repository will be bisected.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D1499

To: dsp, #hg-reviewers, yuja
Cc: mercurial-devel