Re: [PATCH v4 13/13] midx: implement writing incremental MIDX bitmaps

On Mon, Mar 17, 2025 at 10:16:05PM -0400, Jeff King wrote:

On Fri, Mar 14, 2025 at 04:19:00PM -0400, Taylor Blau wrote:

quoted

+write_midx_layer () {
+	n=1
+	if test -f $midx_chain
+	then
+		n="$(($(wc -l <$midx_chain) + 1))"
+	fi
+
+	for i in 1 2
+	do
+		test_commit $n.$i &&
+		git repack -d || return 1
+	done &&
+	git multi-pack-index write --bitmap --incremental
+}
+
+test_expect_success 'write initial MIDX layer' '
+	git repack -ad &&
+	write_midx_layer
+'
+
+test_expect_success 'read bitmap from first MIDX layer' '
+	git rev-list --test-bitmap 1.2
+'
+
+test_expect_success 'write another MIDX layer' '
+	write_midx_layer
+'
+
+test_expect_success 'midx verify with multiple layers' '
+	git multi-pack-index verify
+'

Perhaps a silly suggestion, but do you want to confirm in one of these
tests that there are in fact multiple layers of bitmaps? (I expect it to
be true, but just trying to cover all bases in the test).

I don't think it's a silly suggestion. As you note, we do implicitly
check it further down, but doing something like the following

    test_path_is_dir "$midx_chain" &&
    test_line_count = 2 "$midx_chain" &&

explicitly before calling 'git multi-pack-index verify' would be nice to
have.

Thanks,
Taylor