mirror of
https://github.com/git/git.git
synced 2024-10-30 13:57:54 +01:00
dc39e09942
When processing a `files_ref_store` transaction, it is sometimes necessary to delete some references from the "packed-refs" file. Do that using a reference transaction conducted against the `packed_ref_store`. This change further decouples `files_ref_store` from `packed_ref_store`. It also fixes multiple problems, including the two revealed by test cases added in the previous commit. First, the old code didn't obtain the `packed-refs` lock until `files_transaction_finish()`. This means that a failure to acquire the `packed-refs` lock (e.g., due to contention with another process) wasn't detected until it was too late (problems like this are supposed to be detected in the "prepare" phase). The new code acquires the `packed-refs` lock in `files_transaction_prepare()`, the same stage of the processing when the loose reference locks are being acquired, removing another reason why the "prepare" phase might succeed and the "finish" phase might nevertheless fail. Second, the old code deleted the loose version of a reference before deleting any packed version of the same reference. This left a moment when another process might think that the packed version of the reference is current, which is incorrect. (Even worse, the packed version of the reference can be arbitrarily old, and might even point at an object that has since been garbage-collected.) Third, if a reference deletion fails to acquire the `packed-refs` lock altogether, then the old code might leave the repository in the incorrect state (possibly corrupt) described in the previous paragraph. Now we activate the new "packed-refs" file (sans any references that are being deleted) *before* deleting the corresponding loose references. But we hold the "packed-refs" lock until after the loose references have been finalized, thus preventing a simultaneous "pack-refs" process from packing the loose version of the reference in the time gap, which would otherwise defeat our attempt to delete it. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
480 lines
15 KiB
Bash
Executable file
480 lines
15 KiB
Bash
Executable file
#!/bin/sh
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test_description='Test git update-ref error handling'
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. ./test-lib.sh
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# Create some references, perhaps run pack-refs --all, then try to
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# create some more references. Ensure that the second creation fails
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# with the correct error message.
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# Usage: test_update_rejected <before> <pack> <create> <error>
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# <before> is a ws-separated list of refs to create before the test
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# <pack> (true or false) tells whether to pack the refs before the test
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# <create> is a list of variables to attempt creating
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# <error> is a string to look for in the stderr of update-ref.
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# All references are created in the namespace specified by the current
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# value of $prefix.
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test_update_rejected () {
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before="$1" &&
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pack="$2" &&
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create="$3" &&
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error="$4" &&
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printf "create $prefix/%s $C\n" $before |
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git update-ref --stdin &&
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git for-each-ref $prefix >unchanged &&
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if $pack
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then
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git pack-refs --all
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fi &&
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printf "create $prefix/%s $C\n" $create >input &&
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test_must_fail git update-ref --stdin <input 2>output.err &&
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grep -F "$error" output.err &&
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git for-each-ref $prefix >actual &&
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test_cmp unchanged actual
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}
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Q="'"
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test_expect_success 'setup' '
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git commit --allow-empty -m Initial &&
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C=$(git rev-parse HEAD) &&
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git commit --allow-empty -m Second &&
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D=$(git rev-parse HEAD) &&
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git commit --allow-empty -m Third &&
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E=$(git rev-parse HEAD)
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'
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test_expect_success 'existing loose ref is a simple prefix of new' '
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prefix=refs/1l &&
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test_update_rejected "a c e" false "b c/x d" \
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"$Q$prefix/c$Q exists; cannot create $Q$prefix/c/x$Q"
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'
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test_expect_success 'existing packed ref is a simple prefix of new' '
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prefix=refs/1p &&
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test_update_rejected "a c e" true "b c/x d" \
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"$Q$prefix/c$Q exists; cannot create $Q$prefix/c/x$Q"
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'
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test_expect_success 'existing loose ref is a deeper prefix of new' '
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prefix=refs/2l &&
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test_update_rejected "a c e" false "b c/x/y d" \
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"$Q$prefix/c$Q exists; cannot create $Q$prefix/c/x/y$Q"
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'
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test_expect_success 'existing packed ref is a deeper prefix of new' '
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prefix=refs/2p &&
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test_update_rejected "a c e" true "b c/x/y d" \
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"$Q$prefix/c$Q exists; cannot create $Q$prefix/c/x/y$Q"
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'
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test_expect_success 'new ref is a simple prefix of existing loose' '
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prefix=refs/3l &&
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test_update_rejected "a c/x e" false "b c d" \
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"$Q$prefix/c/x$Q exists; cannot create $Q$prefix/c$Q"
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'
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test_expect_success 'new ref is a simple prefix of existing packed' '
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prefix=refs/3p &&
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test_update_rejected "a c/x e" true "b c d" \
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"$Q$prefix/c/x$Q exists; cannot create $Q$prefix/c$Q"
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'
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test_expect_success 'new ref is a deeper prefix of existing loose' '
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prefix=refs/4l &&
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test_update_rejected "a c/x/y e" false "b c d" \
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"$Q$prefix/c/x/y$Q exists; cannot create $Q$prefix/c$Q"
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'
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test_expect_success 'new ref is a deeper prefix of existing packed' '
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prefix=refs/4p &&
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test_update_rejected "a c/x/y e" true "b c d" \
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"$Q$prefix/c/x/y$Q exists; cannot create $Q$prefix/c$Q"
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'
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test_expect_success 'one new ref is a simple prefix of another' '
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prefix=refs/5 &&
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test_update_rejected "a e" false "b c c/x d" \
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"cannot process $Q$prefix/c$Q and $Q$prefix/c/x$Q at the same time"
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'
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test_expect_success 'empty directory should not fool rev-parse' '
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prefix=refs/e-rev-parse &&
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git update-ref $prefix/foo $C &&
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git pack-refs --all &&
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mkdir -p .git/$prefix/foo/bar/baz &&
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echo "$C" >expected &&
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git rev-parse $prefix/foo >actual &&
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test_cmp expected actual
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'
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test_expect_success 'empty directory should not fool for-each-ref' '
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prefix=refs/e-for-each-ref &&
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git update-ref $prefix/foo $C &&
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git for-each-ref $prefix >expected &&
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git pack-refs --all &&
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mkdir -p .git/$prefix/foo/bar/baz &&
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git for-each-ref $prefix >actual &&
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test_cmp expected actual
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'
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test_expect_success 'empty directory should not fool create' '
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prefix=refs/e-create &&
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mkdir -p .git/$prefix/foo/bar/baz &&
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printf "create %s $C\n" $prefix/foo |
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git update-ref --stdin
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'
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test_expect_success 'empty directory should not fool verify' '
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prefix=refs/e-verify &&
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git update-ref $prefix/foo $C &&
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git pack-refs --all &&
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mkdir -p .git/$prefix/foo/bar/baz &&
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printf "verify %s $C\n" $prefix/foo |
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git update-ref --stdin
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'
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test_expect_success 'empty directory should not fool 1-arg update' '
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prefix=refs/e-update-1 &&
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git update-ref $prefix/foo $C &&
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git pack-refs --all &&
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mkdir -p .git/$prefix/foo/bar/baz &&
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printf "update %s $D\n" $prefix/foo |
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git update-ref --stdin
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'
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test_expect_success 'empty directory should not fool 2-arg update' '
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prefix=refs/e-update-2 &&
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git update-ref $prefix/foo $C &&
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git pack-refs --all &&
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mkdir -p .git/$prefix/foo/bar/baz &&
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printf "update %s $D $C\n" $prefix/foo |
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git update-ref --stdin
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'
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test_expect_success 'empty directory should not fool 0-arg delete' '
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prefix=refs/e-delete-0 &&
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git update-ref $prefix/foo $C &&
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git pack-refs --all &&
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mkdir -p .git/$prefix/foo/bar/baz &&
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printf "delete %s\n" $prefix/foo |
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git update-ref --stdin
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'
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test_expect_success 'empty directory should not fool 1-arg delete' '
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prefix=refs/e-delete-1 &&
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git update-ref $prefix/foo $C &&
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git pack-refs --all &&
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mkdir -p .git/$prefix/foo/bar/baz &&
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printf "delete %s $C\n" $prefix/foo |
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git update-ref --stdin
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'
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# Test various errors when reading the old values of references...
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test_expect_success 'missing old value blocks update' '
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prefix=refs/missing-update &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/foo$Q: unable to resolve reference $Q$prefix/foo$Q
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EOF
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printf "%s\n" "update $prefix/foo $E $D" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err
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'
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test_expect_success 'incorrect old value blocks update' '
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prefix=refs/incorrect-update &&
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git update-ref $prefix/foo $C &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/foo$Q: is at $C but expected $D
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EOF
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printf "%s\n" "update $prefix/foo $E $D" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err
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'
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test_expect_success 'existing old value blocks create' '
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prefix=refs/existing-create &&
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git update-ref $prefix/foo $C &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/foo$Q: reference already exists
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EOF
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printf "%s\n" "create $prefix/foo $E" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err
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'
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test_expect_success 'incorrect old value blocks delete' '
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prefix=refs/incorrect-delete &&
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git update-ref $prefix/foo $C &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/foo$Q: is at $C but expected $D
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EOF
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printf "%s\n" "delete $prefix/foo $D" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err
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'
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test_expect_success 'missing old value blocks indirect update' '
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prefix=refs/missing-indirect-update &&
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git symbolic-ref $prefix/symref $prefix/foo &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/symref$Q: unable to resolve reference $Q$prefix/foo$Q
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EOF
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printf "%s\n" "update $prefix/symref $E $D" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err
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'
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test_expect_success 'incorrect old value blocks indirect update' '
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prefix=refs/incorrect-indirect-update &&
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git symbolic-ref $prefix/symref $prefix/foo &&
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git update-ref $prefix/foo $C &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/symref$Q: is at $C but expected $D
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EOF
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printf "%s\n" "update $prefix/symref $E $D" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err
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'
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test_expect_success 'existing old value blocks indirect create' '
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prefix=refs/existing-indirect-create &&
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git symbolic-ref $prefix/symref $prefix/foo &&
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git update-ref $prefix/foo $C &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/symref$Q: reference already exists
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EOF
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printf "%s\n" "create $prefix/symref $E" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err
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'
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test_expect_success 'incorrect old value blocks indirect delete' '
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prefix=refs/incorrect-indirect-delete &&
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git symbolic-ref $prefix/symref $prefix/foo &&
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git update-ref $prefix/foo $C &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/symref$Q: is at $C but expected $D
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EOF
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printf "%s\n" "delete $prefix/symref $D" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err
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'
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test_expect_success 'missing old value blocks indirect no-deref update' '
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prefix=refs/missing-noderef-update &&
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git symbolic-ref $prefix/symref $prefix/foo &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/symref$Q: reference is missing but expected $D
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EOF
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printf "%s\n" "option no-deref" "update $prefix/symref $E $D" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err
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'
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test_expect_success 'incorrect old value blocks indirect no-deref update' '
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prefix=refs/incorrect-noderef-update &&
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git symbolic-ref $prefix/symref $prefix/foo &&
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git update-ref $prefix/foo $C &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/symref$Q: is at $C but expected $D
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EOF
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printf "%s\n" "option no-deref" "update $prefix/symref $E $D" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err
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'
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test_expect_success 'existing old value blocks indirect no-deref create' '
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prefix=refs/existing-noderef-create &&
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git symbolic-ref $prefix/symref $prefix/foo &&
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git update-ref $prefix/foo $C &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/symref$Q: reference already exists
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EOF
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printf "%s\n" "option no-deref" "create $prefix/symref $E" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err
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'
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test_expect_success 'incorrect old value blocks indirect no-deref delete' '
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prefix=refs/incorrect-noderef-delete &&
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git symbolic-ref $prefix/symref $prefix/foo &&
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git update-ref $prefix/foo $C &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/symref$Q: is at $C but expected $D
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EOF
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printf "%s\n" "option no-deref" "delete $prefix/symref $D" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err
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'
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test_expect_success 'non-empty directory blocks create' '
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prefix=refs/ne-create &&
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mkdir -p .git/$prefix/foo/bar &&
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: >.git/$prefix/foo/bar/baz.lock &&
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test_when_finished "rm -f .git/$prefix/foo/bar/baz.lock" &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/foo$Q: there is a non-empty directory $Q.git/$prefix/foo$Q blocking reference $Q$prefix/foo$Q
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EOF
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printf "%s\n" "update $prefix/foo $C" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/foo$Q: unable to resolve reference $Q$prefix/foo$Q
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EOF
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printf "%s\n" "update $prefix/foo $D $C" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err
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'
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test_expect_success 'broken reference blocks create' '
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prefix=refs/broken-create &&
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mkdir -p .git/$prefix &&
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echo "gobbledigook" >.git/$prefix/foo &&
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test_when_finished "rm -f .git/$prefix/foo" &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/foo$Q: unable to resolve reference $Q$prefix/foo$Q: reference broken
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EOF
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printf "%s\n" "update $prefix/foo $C" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/foo$Q: unable to resolve reference $Q$prefix/foo$Q: reference broken
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EOF
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printf "%s\n" "update $prefix/foo $D $C" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err
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'
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test_expect_success 'non-empty directory blocks indirect create' '
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prefix=refs/ne-indirect-create &&
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git symbolic-ref $prefix/symref $prefix/foo &&
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mkdir -p .git/$prefix/foo/bar &&
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: >.git/$prefix/foo/bar/baz.lock &&
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test_when_finished "rm -f .git/$prefix/foo/bar/baz.lock" &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/symref$Q: there is a non-empty directory $Q.git/$prefix/foo$Q blocking reference $Q$prefix/foo$Q
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EOF
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printf "%s\n" "update $prefix/symref $C" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/symref$Q: unable to resolve reference $Q$prefix/foo$Q
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EOF
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printf "%s\n" "update $prefix/symref $D $C" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err
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'
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test_expect_success 'broken reference blocks indirect create' '
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prefix=refs/broken-indirect-create &&
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git symbolic-ref $prefix/symref $prefix/foo &&
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echo "gobbledigook" >.git/$prefix/foo &&
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test_when_finished "rm -f .git/$prefix/foo" &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/symref$Q: unable to resolve reference $Q$prefix/foo$Q: reference broken
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EOF
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printf "%s\n" "update $prefix/symref $C" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err &&
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cat >expected <<-EOF &&
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fatal: cannot lock ref $Q$prefix/symref$Q: unable to resolve reference $Q$prefix/foo$Q: reference broken
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EOF
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printf "%s\n" "update $prefix/symref $D $C" |
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test_must_fail git update-ref --stdin 2>output.err &&
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test_cmp expected output.err
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'
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test_expect_success 'no bogus intermediate values during delete' '
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prefix=refs/slow-transaction &&
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# Set up a reference with differing loose and packed versions:
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git update-ref $prefix/foo $C &&
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git pack-refs --all &&
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git update-ref $prefix/foo $D &&
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git for-each-ref $prefix >unchanged &&
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# Now try to update the reference, but hold the `packed-refs` lock
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# for a while to see what happens while the process is blocked:
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: >.git/packed-refs.lock &&
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test_when_finished "rm -f .git/packed-refs.lock" &&
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{
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# Note: the following command is intentionally run in the
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# background. We increase the timeout so that `update-ref`
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# attempts to acquire the `packed-refs` lock for longer than
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# it takes for us to do the check then delete it:
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git -c core.packedrefstimeout=3000 update-ref -d $prefix/foo &
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} &&
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pid2=$! &&
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# Give update-ref plenty of time to get to the point where it tries
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# to lock packed-refs:
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sleep 1 &&
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# Make sure that update-ref did not complete despite the lock:
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kill -0 $pid2 &&
|
|
# Verify that the reference still has its old value:
|
|
sha1=$(git rev-parse --verify --quiet $prefix/foo || echo undefined) &&
|
|
case "$sha1" in
|
|
$D)
|
|
# This is what we hope for; it means that nothing
|
|
# user-visible has changed yet.
|
|
: ;;
|
|
undefined)
|
|
# This is not correct; it means the deletion has happened
|
|
# already even though update-ref should not have been
|
|
# able to acquire the lock yet.
|
|
echo "$prefix/foo deleted prematurely" &&
|
|
break
|
|
;;
|
|
$C)
|
|
# This value should never be seen. Probably the loose
|
|
# reference has been deleted but the packed reference
|
|
# is still there:
|
|
echo "$prefix/foo incorrectly observed to be C" &&
|
|
break
|
|
;;
|
|
*)
|
|
# WTF?
|
|
echo "unexpected value observed for $prefix/foo: $sha1" &&
|
|
break
|
|
;;
|
|
esac >out &&
|
|
rm -f .git/packed-refs.lock &&
|
|
wait $pid2 &&
|
|
test_must_be_empty out &&
|
|
test_must_fail git rev-parse --verify --quiet $prefix/foo
|
|
'
|
|
|
|
test_expect_success 'delete fails cleanly if packed-refs file is locked' '
|
|
prefix=refs/locked-packed-refs &&
|
|
# Set up a reference with differing loose and packed versions:
|
|
git update-ref $prefix/foo $C &&
|
|
git pack-refs --all &&
|
|
git update-ref $prefix/foo $D &&
|
|
git for-each-ref $prefix >unchanged &&
|
|
# Now try to delete it while the `packed-refs` lock is held:
|
|
: >.git/packed-refs.lock &&
|
|
test_when_finished "rm -f .git/packed-refs.lock" &&
|
|
test_must_fail git update-ref -d $prefix/foo >out 2>err &&
|
|
git for-each-ref $prefix >actual &&
|
|
test_i18ngrep "Unable to create $Q.*packed-refs.lock$Q: File exists" err &&
|
|
test_cmp unchanged actual
|
|
'
|
|
|
|
test_done
|