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![Jeff King](/assets/img/avatar_default.png)
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>
40 lines
1 KiB
Bash
Executable file
40 lines
1 KiB
Bash
Executable file
#!/bin/sh
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test_description='check bitmap operation with shallow repositories'
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. ./test-lib.sh
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# We want to create a situation where the shallow, grafted
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# view of reachability does not match reality in a way that
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# might cause us to send insufficient objects.
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#
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# We do this with a history that repeats a state, like:
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#
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# A -- B -- C
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# file=1 file=2 file=1
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#
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# and then create a shallow clone to the second commit, B.
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# In a non-shallow clone, that would mean we already have
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# the tree for A. But in a shallow one, we've grafted away
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# A, and fetching A to B requires that the other side send
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# us the tree for file=1.
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test_expect_success 'setup shallow repo' '
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echo 1 >file &&
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git add file &&
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git commit -m orig &&
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echo 2 >file &&
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git commit -a -m update &&
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git clone --no-local --bare --depth=1 . shallow.git &&
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echo 1 >file &&
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git commit -a -m repeat
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'
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test_expect_success 'turn on bitmaps in the parent' '
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git repack -adb
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'
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test_expect_success 'shallow fetch from bitmapped repo' '
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(cd shallow.git && git fetch)
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'
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test_done
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