git-commit-vandalism/t/t5311-pack-bitmaps-shallow.sh

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pack-objects: turn off bitmaps when we see --shallow lines Reachability bitmaps do not work with shallow operations, because they cache a view of the object reachability that represents the true objects. Whereas a shallow repository (or a shallow operation in a repository) is inherently cutting off the object graph with a graft. We explicitly disallow the use of bitmaps in shallow repositories by checking is_repository_shallow(), and we should continue to do that. However, we also want to disallow bitmaps when we are serving a fetch to a shallow client, since we momentarily take on their grafted view of the world. It used to be enough to call is_repository_shallow at the start of pack-objects. Upload-pack wrote the other side's shallow state to a temporary file and pointed the whole pack-objects process at this state with "git --shallow-file", and from the perspective of pack-objects, we really were in a shallow repo. But since b790e0f (upload-pack: send shallow info over stdin to pack-objects, 2014-03-11), we do it differently: we send --shallow lines to pack-objects over stdin, and it registers them itself. This means that our is_repository_shallow check is way too early (we have not been told about the shallowness yet), and that it is insufficient (calling is_repository_shallow is not enough, as the shallow grafts we register do not change its return value). Instead, we can just turn off bitmaps explicitly when we see these lines. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-08-12 06:34:53 +02:00
#!/bin/sh
test_description='check bitmap operation with shallow repositories'
. ./test-lib.sh
# We want to create a situation where the shallow, grafted
# view of reachability does not match reality in a way that
# might cause us to send insufficient objects.
#
# We do this with a history that repeats a state, like:
#
# A -- B -- C
# file=1 file=2 file=1
#
# and then create a shallow clone to the second commit, B.
# In a non-shallow clone, that would mean we already have
# the tree for A. But in a shallow one, we've grafted away
# A, and fetching A to B requires that the other side send
# us the tree for file=1.
test_shallow_bitmaps () {
writeLookupTable=false
for i in "$@"
do
case $i in
"pack.writeBitmapLookupTable") writeLookupTable=true;;
esac
done
test_expect_success 'setup shallow repo' '
rm -rf * .git &&
git init &&
git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
echo 1 >file &&
git add file &&
git commit -m orig &&
echo 2 >file &&
git commit -a -m update &&
git clone --no-local --bare --depth=1 . shallow.git &&
echo 1 >file &&
git commit -a -m repeat
'
test_expect_success 'turn on bitmaps in the parent' '
git repack -adb
'
test_expect_success 'shallow fetch from bitmapped repo' '
(cd shallow.git && git fetch)
'
}
test_shallow_bitmaps
test_shallow_bitmaps "pack.writeBitmapLookupTable"
pack-objects: turn off bitmaps when we see --shallow lines Reachability bitmaps do not work with shallow operations, because they cache a view of the object reachability that represents the true objects. Whereas a shallow repository (or a shallow operation in a repository) is inherently cutting off the object graph with a graft. We explicitly disallow the use of bitmaps in shallow repositories by checking is_repository_shallow(), and we should continue to do that. However, we also want to disallow bitmaps when we are serving a fetch to a shallow client, since we momentarily take on their grafted view of the world. It used to be enough to call is_repository_shallow at the start of pack-objects. Upload-pack wrote the other side's shallow state to a temporary file and pointed the whole pack-objects process at this state with "git --shallow-file", and from the perspective of pack-objects, we really were in a shallow repo. But since b790e0f (upload-pack: send shallow info over stdin to pack-objects, 2014-03-11), we do it differently: we send --shallow lines to pack-objects over stdin, and it registers them itself. This means that our is_repository_shallow check is way too early (we have not been told about the shallowness yet), and that it is insufficient (calling is_repository_shallow is not enough, as the shallow grafts we register do not change its return value). Instead, we can just turn off bitmaps explicitly when we see these lines. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-08-12 06:34:53 +02:00
test_done