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path: root/t/t5309-pack-delta-cycles.sh
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2018-05-14t: skip pack tests if not using SHA-1Libravatar brian m. carlson1-0/+6
These tests rely on creating packs with specially named objects which are necessarily dependent on the hash used. Skip these tests if we're not using SHA-1. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-08-24test index-pack on packs with recoverable delta cyclesLibravatar Jeff King1-0/+18
The previous commit added tests to show that index-pack correctly bails in unrecoverable situations. There are some situations where the data could be recovered, but it is not currently: 1. If we can break the cycle using an object from another pack via --fix-thin. 2. If we can break the cycle using a duplicate of one of the objects found in the same pack. Note that neither of these is particularly high priority; a delta cycle within a pack should never occur, and we have no record of even a buggy git implementation creating such a pack. However, it's worth adding these tests for two reasons. One, to document that we do not currently handle the situation, even though it is possible. And two, to exercise the code that runs in this situation; even though it fails, by running it we can confirm that index-pack detects the situation and aborts, and does not misbehave (e.g., by following the cycle in an infinite loop). In both cases, we hit an assert that aborts index-pack. Signed-off-by: Jeff King <peff@peff.net> Acked-by: Nicolas Pitre <nico@fluxnic.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-08-24add tests for indexing packs with delta cyclesLibravatar Jeff King1-0/+59
If we receive a broken or malicious pack from a remote, we will feed it to index-pack. As index-pack processes the objects as a stream, reconstructing and hashing each object to get its name, it is not very susceptible to doing the wrong with bad data (it simply notices that the data is bogus and aborts). However, one question raised on the list is whether it could be susceptible to problems during the delta-resolution phase. In particular, can a cycle in the packfile deltas cause us to go into an infinite loop or cause any other problem? The answer is no. We cannot have a cycle of delta-base offsets, because they go only in one direction (the OFS_DELTA object mentions its base by an offset towards the beginning of the file, and we explicitly reject negative offsets). We can have a cycle of REF_DELTA objects, which refer to base objects by sha1 name. However, index-pack does not know these sha1 names ahead of time; it has to reconstruct the objects to get their names, and it cannot do so if there is a delta cycle (in other words, it does not even realize there is a cycle, but only that there are items that cannot be resolved). Even though we can reason out that index-pack should handle this fine, let's add a few tests to make sure it behaves correctly. Signed-off-by: Jeff King <peff@peff.net> Acked-by: Nicolas Pitre <nico@fluxnic.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>