[PATCH v2 0/2] connected: fix the connectivity check with alternates in deepening fetches

In a deepening fetch the connectivity check runs rev-list with "--alternate-refs" as a positive revision, so it walks the alternate's whole history. With a 7M-object alternate the check takes 227s after a fetch that received an empty pack.

Changes since v1:

 * The connectivity check negates "--alternate-refs" in both cases,
   as Junio suggested, instead of dropping it for deepening fetches.
   The alternate's refs are a boundary like our own refs. Compared to
   Junio's diff, "--alternate-refs" moved up next to "--all" so that
   the comment above "--not" covers all of the boundary arguments.

 * New second patch: odb_for_each_alternate_ref() ignores the refs of
   shallow and grafted alternates, so that neither the connectivity
   check, nor fetch-pack's "have"s, nor receive-pack's ".have"s treat
   history that the alternate does not have as present. Partial
   clones are not detected, see the commit message.

v1: https://lore.kernel.org/git/20261014103507.35317-1-iwiedler@gitlab.com/

Igor Wiedler (2):
  connected: negate alternate refs in deepening fetches too
  odb: ignore refs of shallow and grafted alternates

 Documentation/rev-list-options.adoc |  7 ++++---
 connected.c                         |  6 ++++--
 odb.c                               | 11 +++++++++++
 t/t5618-alternate-refs.sh           | 25 +++++++++++++++++++++++++
 4 files changed, 44 insertions(+), 5 deletions(-)

base-commit: 6de20f6092dcf9bdb1c8efe03db4b70c82b423dd