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

From: Junio C Hamano <[email-masked]>
Date: Fri, 23 Jul 2021 14:20:59 -0700

Jonathan Tan <[email-masked]> writes:

> @@ -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);
> +

It's so nice when a "fix" to an issue can be this simple.

Thanks; will queue.

>  	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