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diff --git a/t/t6501-freshen-objects.sh b/t/t6501-freshen-objects.sh
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+++ b/t/t6501-freshen-objects.sh
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+#!/bin/sh
+#
+# This test covers the handling of objects which might have old
+# mtimes in the filesystem (because they were used previously)
+# and are just now becoming referenced again.
+#
+# We're going to do two things that are a little bit "fake" to
+# help make our simulation easier:
+#
+#   1. We'll turn off reflogs. You can still run into
+#      problems with reflogs on, but your objects
+#      don't get pruned until both the reflog expiration
+#      has passed on their references, _and_ they are out
+#      of prune's expiration period. Dropping reflogs
+#      means we only have to deal with one variable in our tests,
+#      but the results generalize.
+#
+#   2. We'll use a temporary index file to create our
+#      works-in-progress. Most workflows would mention
+#      referenced objects in the index, which prune takes
+#      into account. However, many operations don't. For
+#      example, a partial commit with "git commit foo"
+#      will use a temporary index. Or they may not need
+#      an index at all (e.g., creating a new commit
+#      to refer to an existing tree).
+
+test_description='check pruning of dependent objects'
+. ./test-lib.sh
+
+# We care about reachability, so we do not want to use
+# the normal test_commit, which creates extra tags.
+add () {
+	echo "$1" >"$1" &&
+	git add "$1"
+}
+commit () {
+	test_tick &&
+	add "$1" &&
+	git commit -m "$1"
+}
+
+maybe_repack () {
+	if test -n "$repack"; then
+		git repack -ad
+	fi
+}
+
+for repack in '' true; do
+	title=${repack:+repack}
+	title=${title:-loose}
+
+	test_expect_success "make repo completely empty ($title)" '
+		rm -rf .git &&
+		git init
+	'
+
+	test_expect_success "disable reflogs ($title)" '
+		git config core.logallrefupdates false &&
+		rm -rf .git/logs
+	'
+
+	test_expect_success "setup basic history ($title)" '
+		commit base
+	'
+
+	test_expect_success "create and abandon some objects ($title)" '
+		git checkout -b experiment &&
+		commit abandon &&
+		maybe_repack &&
+		git checkout master &&
+		git branch -D experiment
+	'
+
+	test_expect_success "simulate time passing ($title)" '
+		find .git/objects -type f |
+		xargs test-chmtime -v -86400
+	'
+
+	test_expect_success "start writing new commit with old blob ($title)" '
+		tree=$(
+			GIT_INDEX_FILE=index.tmp &&
+			export GIT_INDEX_FILE &&
+			git read-tree HEAD &&
+			add unrelated &&
+			add abandon &&
+			git write-tree
+		)
+	'
+
+	test_expect_success "simultaneous gc ($title)" '
+		git gc --prune=12.hours.ago
+	'
+
+	test_expect_success "finish writing out commit ($title)" '
+		commit=$(echo foo | git commit-tree -p HEAD $tree) &&
+		git update-ref HEAD $commit
+	'
+
+	# "abandon" blob should have been rescued by reference from new tree
+	test_expect_success "repository passes fsck ($title)" '
+		git fsck
+	'
+
+	test_expect_success "abandon objects again ($title)" '
+		git reset --hard HEAD^ &&
+		find .git/objects -type f |
+		xargs test-chmtime -v -86400
+	'
+
+	test_expect_success "start writing new commit with same tree ($title)" '
+		tree=$(
+			GIT_INDEX_FILE=index.tmp &&
+			export GIT_INDEX_FILE &&
+			git read-tree HEAD &&
+			add abandon &&
+			add unrelated &&
+			git write-tree
+		)
+	'
+
+	test_expect_success "simultaneous gc ($title)" '
+		git gc --prune=12.hours.ago
+	'
+
+	# tree should have been refreshed by write-tree
+	test_expect_success "finish writing out commit ($title)" '
+		commit=$(echo foo | git commit-tree -p HEAD $tree) &&
+		git update-ref HEAD $commit
+	'
+done
+
+test_done