[PATCH 0/3] Use default values from settings instead of config

Hi everyone! This patch was created in response to something we observed in
Google, where fsck failed to detect that the commit graph was invalid. We
initially assumed that fsck never checked the commit graph, but it turns out
that it does so only when core.commitgraph is set, even though we set defaults
for "whether to use the commit graph" in the repository settings.

Instead of using the config, let's use repository settings where
available. Replace core.commitGraph and core.multiPackIndex with their
equivalent repository settings in fsck and gc.

I'm fairly new to the codebase (this is my first patch!), so I have some
questions/concerns that I wasn't able to figure out:
- prepare_repo_settings() may have undesirable side effects or may
  not always be callable
- I can't find tests that cover the changes to gc, so I'm not sure if my
  understanding of gc is correct

Let me know if there is something I'm missing :)

CC-ing Derrick Stolee who has done work on both prepare_repo_settings and gc.

Glen Choo (3):
  fsck: verify commit graph when implicitly enabled
  fsck: verify multi-pack-index when implictly enabled
  gc: perform incremental repack when implictly enabled

 builtin/fsck.c              |  5 +++--
 builtin/gc.c                |  5 ++---
 t/t5318-commit-graph.sh     | 23 ++++++++++++++++++++++-
 t/t5319-multi-pack-index.sh | 15 ++++++++++++++-
 4 files changed, 41 insertions(+), 7 deletions(-)

-- 
2.33.0.309.g3052b89438-goog