Re: [PATCH 2/2] cache-tree: prefetch in partial clone read-tree

@@ -466,6 +470,9 @@ int cache_tree_update(struct index_state *istate, int flags)
 	if (!istate->cache_tree)
 		istate->cache_tree = cache_tree();
 
+	if (!(flags & WRITE_TREE_MISSING_OK) && has_promisor_remote())
+		prefetch_cache_entries(istate, must_check_existence);
+

 	trace_performance_enter();
 	trace2_region_enter("cache_tree", "update", the_repository);
 	i = update_one(istate->cache_tree, istate->cache, istate->cache_nr,

diff --git a/t/t1022-read-tree-partial-clone.sh b/t/t1022-read-tree-partial-clone.sh
new file mode 100755
index 0000000000..a763e27c7d
--- /dev/null
+++ b/t/t1022-read-tree-partial-clone.sh

@@ -0,0 +1,33 @@
+#!/bin/sh
+
+test_description='git read-tree in partial clones'
+
+TEST_NO_CREATE_REPO=1
+
+GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
+export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
+
+. ./test-lib.sh
+
+test_expect_success 'read-tree in partial clone prefetches in one batch' '
+	test_when_finished "rm -rf server client trace" &&
+
+	git init server &&
+	echo foo >server/one &&
+	echo bar >server/two &&
+	git -C server add one two &&
+	git -C server commit -m "initial commit" &&
+	TREE=$(git -C server rev-parse HEAD^{tree}) &&
+
+	git -C server config uploadpack.allowfilter 1 &&
+	git -C server config uploadpack.allowanysha1inwant 1 &&
+	git clone --bare --filter=blob:none "file://$(pwd)/server" client &&
+	GIT_TRACE_PACKET="$(pwd)/trace" git -C client read-tree $TREE &&
+
+	# "done" marks the end of negotiation (once per fetch). Expect that
+	# only one fetch occurs.
+	grep "fetch> done" trace >donelines &&
+	test_line_count = 1 donelines
+'
+
+test_done