[PATCH v3 0/4] object checking related additions and fixes for bundles in fetches

While attempting to fix a reference negotiation bug in bundle-uri, we discovered that the fetch process are missing some helpful object validation logic when processing bundles. The main issues are:

 * In the bundle-uri scenario, we did not validate object IDs before writing
   bundle references. This is the root cause of the original negotiation bug
   in bundle-uri, and can cause potential repository corruption.
 * The existing fetch.fsckObjects and transfer.fsckObjects are not detected
   when directly fetching bundles. In fact there is no object validation
   support for unbundle.

The first patch fixes the bundle-uri negotiation issue by dropping the REF_SKIP_OID_VERIFICATION flag when writing bundle references.

Patch 2~4 extend bundle.c:unbundle with a unbundle_fsck_flags to control object fscking in different scenarios, the implementation mainly follows what Junio suggested on the mailing list.

Xing Xin (4):
  bundle-uri: verify oid before writing refs
  unbundle: introduce unbundle_fsck_flags for fsckobjects handling
  fetch-pack: expose fsckObjects configuration logic
  unbundle: introduce new option UNBUNDLE_FSCK_FOLLOW_FETCH

 builtin/bundle.c            |   2 +-
 bundle-uri.c                |   5 +-
 bundle.c                    |  20 ++++-
 bundle.h                    |   9 +-
 fetch-pack.c                |  18 ++--
 fetch-pack.h                |   2 +
 t/t5558-clone-bundle-uri.sh | 163 +++++++++++++++++++++++++++++++++++-
 t/t5607-clone-bundle.sh     |  23 +++++
 transport.c                 |   2 +-
 9 files changed, 227 insertions(+), 17 deletions(-)

base-commit: b9cfe4845cb2562584837bc0101c0ab76490a239
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1730%2Fblanet%2Fxx%2Fbundle-uri-bug-using-bundle-list-v3
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1730/blanet/xx/bundle-uri-bug-using-bundle-list-v3
Pull-Request: https://github.com/gitgitgadget/git/pull/1730

Range-diff vs v2:

 1:  8bdeacf1360 = 1:  8f488a5eeaa bundle-uri: verify oid before writing refs
 -:  ----------- > 2:  057c697970f unbundle: introduce unbundle_fsck_flags for fsckobjects handling
 -:  ----------- > 3:  67401d4fbcb fetch-pack: expose fsckObjects configuration logic
 -:  ----------- > 4:  c19b8f633cb unbundle: introduce new option UNBUNDLE_FSCK_FOLLOW_FETCH