[PATCH v6 18/18] commit-graph: test verify across alternates

[Derrick Stolee via GitGitGadget]

From: Derrick Stolee <dsto...@microsoft.com>

The 'git commit-graph verify' subcommand loads a commit-graph from
a given object directory instead of using the standard method
prepare_commit_graph(). During development of load_commit_graph_chain(),
a version did not include prepare_alt_odb() as it was previously
run by prepare_commit_graph() in most cases.

Add a test that prevents that mistake from happening again.

Signed-off-by: Derrick Stolee <dsto...@microsoft.com>
---
 t/t5324-split-commit-graph.sh | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/t/t5324-split-commit-graph.sh b/t/t5324-split-commit-graph.sh
index fc0d00751c..03f45a1ed9 100755
--- a/t/t5324-split-commit-graph.sh
+++ b/t/t5324-split-commit-graph.sh
@@ -237,6 +237,7 @@ corrupt_file() {
        file=$1
        pos=$2
        data="${3:-\0}"
+       chmod a+w "$file" &&
        printf "$data" | dd of="$file" bs=1 seek="$pos" conv=notrunc
 }
 
@@ -295,6 +296,24 @@ test_expect_success 'verify after commit-graph-chain 
corruption' '
        )
 '
 
+test_expect_success 'verify across alternates' '
+       git clone --no-hardlinks . verify-alt &&
+       (
+               cd verify-alt &&
+               rm -rf $graphdir &&
+               altdir="$(pwd)/../.git/objects" &&
+               echo "$altdir" >.git/objects/info/alternates &&
+               git commit-graph verify --object-dir="$altdir/" &&
+               test_commit extra &&
+               git commit-graph write --reachable --split &&
+               tip_file=$graphdir/graph-$(tail -n 1 
$graphdir/commit-graph-chain).graph &&
+               corrupt_file "$tip_file" 100 "\01" &&
+               test_must_fail git commit-graph verify --shallow 2>test_err &&
+               grep -v "^+" test_err >err &&
+               test_i18ngrep "commit-graph has incorrect fanout value" err
+       )
+'
+
 test_expect_success 'add octopus merge' '
        git reset --hard commits/10 &&
        git merge commits/3 commits/4 &&
-- 
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