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Diffstat (limited to 'third_party/git/t/t5314-pack-cycle-detection.sh')
| -rwxr-xr-x | third_party/git/t/t5314-pack-cycle-detection.sh | 112 |
1 files changed, 0 insertions, 112 deletions
diff --git a/third_party/git/t/t5314-pack-cycle-detection.sh b/third_party/git/t/t5314-pack-cycle-detection.sh deleted file mode 100755 index 0aec8619e22d..000000000000 --- a/third_party/git/t/t5314-pack-cycle-detection.sh +++ /dev/null @@ -1,112 +0,0 @@ -#!/bin/sh - -test_description='test handling of inter-pack delta cycles during repack - -The goal here is to create a situation where we have two blobs, A and B, with A -as a delta against B in one pack, and vice versa in the other. Then if we can -persuade a full repack to find A from one pack and B from the other, that will -give us a cycle when we attempt to reuse those deltas. - -The trick is in the "persuade" step, as it depends on the internals of how -pack-objects picks which pack to reuse the deltas from. But we can assume -that it does so in one of two general strategies: - - 1. Using a static ordering of packs. In this case, no inter-pack cycles can - happen. Any objects with a delta relationship must be present in the same - pack (i.e., no "--thin" packs on disk), so we will find all related objects - from that pack. So assuming there are no cycles within a single pack (and - we avoid generating them via pack-objects or importing them via - index-pack), then our result will have no cycles. - - So this case should pass the tests no matter how we arrange things. - - 2. Picking the next pack to examine based on locality (i.e., where we found - something else recently). - - In this case, we want to make sure that we find the delta versions of A and - B and not their base versions. We can do this by putting two blobs in each - pack. The first is a "dummy" blob that can only be found in the pack in - question. And then the second is the actual delta we want to find. - - The two blobs must be present in the same tree, not present in other trees, - and the dummy pathname must sort before the delta path. - -The setup below focuses on case 2. We have two commits HEAD and HEAD^, each -which has two files: "dummy" and "file". Then we can make two packs which -contain: - - [pack one] - HEAD:dummy - HEAD:file (as delta against HEAD^:file) - HEAD^:file (as base) - - [pack two] - HEAD^:dummy - HEAD^:file (as delta against HEAD:file) - HEAD:file (as base) - -Then no matter which order we start looking at the packs in, we know that we -will always find a delta for "file", because its lookup will always come -immediately after the lookup for "dummy". -' -. ./test-lib.sh - - - -# Create a pack containing the tree $1 and blob $1:file, with -# the latter stored as a delta against $2:file. -# -# We convince pack-objects to make the delta in the direction of our choosing -# by marking $2 as a preferred-base edge. That results in $1:file as a thin -# delta, and index-pack completes it by adding $2:file as a base. -# -# Note that the two variants of "file" must be similar enough to convince git -# to create the delta. -make_pack () { - { - printf '%s\n' "-$(git rev-parse $2)" - printf '%s dummy\n' "$(git rev-parse $1:dummy)" - printf '%s file\n' "$(git rev-parse $1:file)" - } | - git pack-objects --stdout | - git index-pack --stdin --fix-thin -} - -test_expect_success 'setup' ' - test-tool genrandom base 4096 >base && - for i in one two - do - # we want shared content here to encourage deltas... - cp base file && - echo $i >>file && - - # ...whereas dummy should be short, because we do not want - # deltas that would create duplicates when we --fix-thin - echo $i >dummy && - - git add file dummy && - test_tick && - git commit -m $i || - return 1 - done && - - make_pack HEAD^ HEAD && - make_pack HEAD HEAD^ -' - -test_expect_success 'repack' ' - # We first want to check that we do not have any internal errors, - # and also that we do not hit the last-ditch cycle-breaking code - # in write_object(), which will issue a warning to stderr. - git repack -ad 2>stderr && - test_must_be_empty stderr && - - # And then double-check that the resulting pack is usable (i.e., - # we did not fail to notice any cycles). We know we are accessing - # the objects via the new pack here, because "repack -d" will have - # removed the others. - git cat-file blob HEAD:file >/dev/null && - git cat-file blob HEAD^:file >/dev/null -' - -test_done |