merge-tree: fail with a non-zero exit code on missing tree objects

When `git merge-tree` encounters a missing tree object, it should error
out and not continue quietly as if nothing had happened.

However, as of time of writing, `git merge-tree` _does_ continue, and
then offers the empty tree as result.

Let's fix this.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/merge-ort.c b/merge-ort.c
index 6491070d965835f9202b68fbdae72cb6cd6c987f..c37fc035f1334eeecef098580d87c404f13088c8 100644 (file)
--- a/merge-ort.c
+++ b/merge-ort.c
@@ -1659,9 +1659,10 @@ static int collect_merge_info(struct merge_options *opt,
        info.data = opt;
        info.show_all_errors = 1;
 
-       parse_tree(merge_base);
-       parse_tree(side1);
-       parse_tree(side2);
+       if (parse_tree(merge_base) < 0 ||
+           parse_tree(side1) < 0 ||
+           parse_tree(side2) < 0)
+               return -1;
        init_tree_desc(t + 0, merge_base->buffer, merge_base->size);
        init_tree_desc(t + 1, side1->buffer, side1->size);
        init_tree_desc(t + 2, side2->buffer, side2->size);

diff --git a/t/t4301-merge-tree-write-tree.sh b/t/t4301-merge-tree-write-tree.sh
index 7d0fa74da74c855a7114629b634f7ea92ee0427a..908c9b540c816ff2aacd7d0187ba6080dfd27d81 100755 (executable)
--- a/t/t4301-merge-tree-write-tree.sh
+++ b/t/t4301-merge-tree-write-tree.sh
@@ -951,4 +951,15 @@ test_expect_success '--merge-base with tree OIDs' '
        test_cmp with-commits with-trees
 '
 
+test_expect_success 'error out on missing tree objects' '
+       git init --bare missing-tree.git &&
+       git rev-list side3 >list &&
+       git rev-parse side3^: >>list &&
+       git pack-objects missing-tree.git/objects/pack/side3-tree-is-missing <list &&
+       side3=$(git rev-parse side3) &&
+       test_must_fail git --git-dir=missing-tree.git merge-tree $side3^ $side3 >actual 2>err &&
+       test_grep "Could not read $(git rev-parse $side3:)" err &&
+       test_must_be_empty actual
+'
+
 test_done