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![Jeff King](/assets/img/avatar_default.png)
When we try to write a loose object file, we first check whether that object already exists. If so, we skip the write as an optimization. However, this can interfere with prune's strategy of using mtimes to mark files in progress. For example, if a branch contains a particular tree object and is deleted, that tree object may become unreachable, and have an old mtime. If a new operation then tries to write the same tree, this ends up as a noop; we notice we already have the object and do nothing. A prune running simultaneously with this operation will see the object as old, and may delete it. We can solve this by "freshening" objects that we avoid writing by updating their mtime. The algorithm for doing so is essentially the same as that of has_sha1_file. Therefore we provide a new (static) interface "check_and_freshen", which finds and optionally freshens the object. It's trivial to implement freshening and simple checking by tweaking a single parameter. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
133 lines
3.3 KiB
Bash
Executable file
133 lines
3.3 KiB
Bash
Executable file
#!/bin/sh
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#
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# This test covers the handling of objects which might have old
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# mtimes in the filesystem (because they were used previously)
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# and are just now becoming referenced again.
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#
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# We're going to do two things that are a little bit "fake" to
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# help make our simulation easier:
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#
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# 1. We'll turn off reflogs. You can still run into
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# problems with reflogs on, but your objects
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# don't get pruned until both the reflog expiration
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# has passed on their references, _and_ they are out
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# of prune's expiration period. Dropping reflogs
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# means we only have to deal with one variable in our tests,
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# but the results generalize.
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#
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# 2. We'll use a temporary index file to create our
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# works-in-progress. Most workflows would mention
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# referenced objects in the index, which prune takes
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# into account. However, many operations don't. For
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# example, a partial commit with "git commit foo"
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# will use a temporary index. Or they may not need
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# an index at all (e.g., creating a new commit
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# to refer to an existing tree).
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test_description='check pruning of dependent objects'
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. ./test-lib.sh
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# We care about reachability, so we do not want to use
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# the normal test_commit, which creates extra tags.
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add () {
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echo "$1" >"$1" &&
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git add "$1"
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}
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commit () {
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test_tick &&
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add "$1" &&
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git commit -m "$1"
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}
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maybe_repack () {
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if test -n "$repack"; then
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git repack -ad
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fi
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}
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for repack in '' true; do
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title=${repack:+repack}
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title=${title:-loose}
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test_expect_success "make repo completely empty ($title)" '
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rm -rf .git &&
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git init
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'
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test_expect_success "disable reflogs ($title)" '
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git config core.logallrefupdates false &&
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rm -rf .git/logs
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'
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test_expect_success "setup basic history ($title)" '
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commit base
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'
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test_expect_success "create and abandon some objects ($title)" '
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git checkout -b experiment &&
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commit abandon &&
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maybe_repack &&
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git checkout master &&
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git branch -D experiment
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'
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test_expect_success "simulate time passing ($title)" '
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find .git/objects -type f |
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xargs test-chmtime -v -86400
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'
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test_expect_success "start writing new commit with old blob ($title)" '
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tree=$(
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GIT_INDEX_FILE=index.tmp &&
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export GIT_INDEX_FILE &&
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git read-tree HEAD &&
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add unrelated &&
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add abandon &&
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git write-tree
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)
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'
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test_expect_success "simultaneous gc ($title)" '
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git gc --prune=12.hours.ago
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'
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test_expect_success "finish writing out commit ($title)" '
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commit=$(echo foo | git commit-tree -p HEAD $tree) &&
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git update-ref HEAD $commit
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'
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# "abandon" blob should have been rescued by reference from new tree
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test_expect_success "repository passes fsck ($title)" '
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git fsck
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'
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test_expect_success "abandon objects again ($title)" '
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git reset --hard HEAD^ &&
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find .git/objects -type f |
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xargs test-chmtime -v -86400
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'
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test_expect_success "start writing new commit with same tree ($title)" '
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tree=$(
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GIT_INDEX_FILE=index.tmp &&
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export GIT_INDEX_FILE &&
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git read-tree HEAD &&
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add abandon &&
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add unrelated &&
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git write-tree
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)
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'
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test_expect_success "simultaneous gc ($title)" '
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git gc --prune=12.hours.ago
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'
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# tree should have been refreshed by write-tree
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test_expect_success "finish writing out commit ($title)" '
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commit=$(echo foo | git commit-tree -p HEAD $tree) &&
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git update-ref HEAD $commit
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'
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done
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test_done
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