Subject: [PATCH v2 0/2] Fail early when partial clone prefetch fails

From: Jonathan Tan <[email-masked]>
Date: Tue, 4 Oct 2022 14:13:39 -0700

Thanks everyone for your comments. I don't think that there is a test 
for when a lazy fetch fails, for some reason, so I added one.

Jonathan Tan (2):
  promisor-remote: remove a return value
  promisor-remote: die upon failing fetch

 object-file.c            |  4 ----
 promisor-remote.c        | 23 ++++++++++++++---------
 promisor-remote.h        | 11 +++++------
 t/t0410-partial-clone.sh | 14 ++++++++++++++
 4 files changed, 33 insertions(+), 19 deletions(-)

Range-diff against v1:
1:  fdb35bc9a6 ! 1:  207332c2df promisor-remote: remove a return value
    @@ Commit message
         No caller of promisor_remote_get_direct() is checking its return value,
         so remove it.
     
    +    Not checking the return value means that the user would not know
    +    whether the failure of reading an object is due to the promisor remote
    +    not supplying the object or because of local repository corruption, but
    +    this will be fixed in a subsequent patch.
    +
         Signed-off-by: Jonathan Tan <[email-masked]>
         Signed-off-by: Junio C Hamano <[email-masked]>
     
2:  06a649b01a ! 2:  9bbf130c2c promisor-remote: die upon failing fetch
    @@ Commit message
         When this batch prefetch fails, these commands fall back to the
         sequential fetches. But at $DAYJOB we have noticed that this results in
         a bad user experience: a command would take unexpectedly long to finish
    -    if the batch prefetch would fail for some intermittent reason, but all
    -    subsequent fetches would work. It would be a better user experience for
    -    such a command would just fail.
    +    (and possibly use up a lot of bandwidth) if the batch prefetch would
    +    fail for some intermittent reason, but all subsequent fetches would
    +    work. It would be a better user experience for such a command would
    +    just fail.
     
         Therefore, make it a fatal error if the prefetch fails and at least one
         object being fetched is known to be a promisor object. (The latter
    @@ promisor-remote.c: void promisor_remote_get_direct(struct repository *repo,
      	if (to_free)
      		free(remaining_oids);
      }
    +
    + ## t/t0410-partial-clone.sh ##
    +@@ t/t0410-partial-clone.sh: test_expect_success 'fetching of missing objects' '
    + 	grep "$HASH" out
    + '
    + 
    ++test_expect_success 'fetching of a promised object that promisor remote no longer has' '
    ++	rm -f err &&
    ++	test_create_repo unreliable-server &&
    ++	git -C unreliable-server config uploadpack.allowanysha1inwant 1 &&
    ++	git -C unreliable-server config uploadpack.allowfilter 1 &&
    ++	test_commit -C unreliable-server foo &&
    ++
    ++	git clone --filter=blob:none --no-checkout "file://$(pwd)/unreliable-server" unreliable-client &&
    ++
    ++	rm -rf unreliable-server/.git/objects/* &&
    ++	test_must_fail git -C unreliable-client checkout HEAD 2>err &&
    ++	grep "could not fetch.*from promisor remote" err
    ++'
    ++
    + test_expect_success 'fetching of missing objects works with ref-in-want enabled' '
    + 	# ref-in-want requires protocol version 2
    + 	git -C server config protocol.version 2 &&
-- 
2.38.0.rc1.362.ged0d419d3c-goog