commit-graph: test --split across alternate without --split

We allow sharing commit-graph files across alternates. When we are
writing a split commit-graph, we allow adding tip graph files that
are not in the alternate, but include commits from our local repo.

However, if our alternate is not using the split commit-graph format,
its file is at .git/objects/info/commit-graph and we are trying to
write files in .git/objects/info/commit-graphs/graph-{hash}.graph.

We already have logic to ensure we do not merge across alternate
boundaries, but we also cannot have a commit-graph chain to our
alternate if uses the old filename structure.

Create a test that verifies we create a new split commit-graph
with only one level and we do not modify the existing commit-graph
in the alternate.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/t5324-split-commit-graph.sh b/t/t5324-split-commit-graph.sh
index 704def70bbce3ae974ee3a9707377f076ae7aa08..130f2baf44d7a305a2c0e78ff80b9c0d140a7e74 100755 (executable)
--- a/t/t5324-split-commit-graph.sh
+++ b/t/t5324-split-commit-graph.sh
@@ -301,4 +301,19 @@ test_expect_success 'add octopus merge' '
 
 graph_git_behavior 'graph exists' merge/octopus commits/12
 
+test_expect_success 'split across alternate where alternate is not split' '
+       git commit-graph write --reachable &&
+       test_path_is_file .git/objects/info/commit-graph &&
+       cp .git/objects/info/commit-graph . &&
+       git clone --no-hardlinks . alt-split &&
+       (
+               cd alt-split &&
+               echo "$(pwd)"/../.git/objects >.git/objects/info/alternates &&
+               test_commit 18 &&
+               git commit-graph write --reachable --split &&
+               test_line_count = 1 $graphdir/commit-graph-chain
+       ) &&
+       test_cmp commit-graph .git/objects/info/commit-graph
+'
+
 test_done