I recently looked into issues where git merge-tree calls returned bogus data (in one instance returning an empty tree for non-empty merge parents). By the time I had a look at the corresponding repository, the issue was no longer reproducible, but a closer look at the code combined with some manual experimenting turned up the fact that missing tree objects aren't handled as errors by git merge-tree. While at it, I added a commit on top that tries to catch all remaining unchecked parse_tree() calls. This patch series is based on 5f43cf5b2e4 (merge-tree: accept 3 trees as arguments, 2024-01-28) (the original tip commit of js/merge-tree-3-trees) because I introduced three unchecked parse_tree() calls in that topic. Changes since v2: * Fixed the new "missing tree object" test case in t4301 that succeeded for the wrong reason. * Adjusted the new "missing blob object" test case to avoid succeeding for the wrong reason. * Simplified the "missing blob object" test case. Changes since v1: * Simplified the test case, avoiding a subshell and a pipe in the process. * Added a patch to remove a superfluous subtree->object.parsed guard around a parse_tree(subtree) call. Johannes Schindelin (5): merge-tree: fail with a non-zero exit code on missing tree objects merge-ort: do check `parse_tree()`'s return value t4301: verify that merge-tree fails on missing blob objects Always check `parse_tree*()`'s return value cache-tree: avoid an unnecessary check builtin/checkout.c | 19 ++++++++++++++++--- builtin/clone.c | 3 ++- builtin/commit.c | 3 ++- builtin/merge-tree.c | 6 ++++++ builtin/read-tree.c | 3 ++- builtin/reset.c | 4 ++++ cache-tree.c | 4 ++-- merge-ort.c | 16 +++++++++++----- merge-recursive.c | 3 ++- merge.c | 5 ++++- reset.c | 5 +++++ sequencer.c | 4 ++++ t/t4301-merge-tree-write-tree.sh | 27 +++++++++++++++++++++++++++ 13 files changed, 87 insertions(+), 15 deletions(-) base-commit: 5f43cf5b2e4b68386d3774bce880b0f74d801635 Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1651%2Fdscho%2Fmerge-tree-and-missing-objects-v3 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1651/dscho/merge-tree-and-missing-objects-v3 Pull-Request: https://github.com/gitgitgadget/git/pull/1651 Range-diff vs v2: 1: 01dfd66568c ! 1: 11b9cd8c5da merge-tree: fail with a non-zero exit code on missing tree objects @@ t/t4301-merge-tree-write-tree.sh: test_expect_success '--merge-base with tree OI +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 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 && ++ test_must_fail git --git-dir=missing-tree.git merge-tree $side3^ $side3 >actual 2>err && ++ test_grep "Could not read $(git rev-parse $side3:)" err && + test_must_be_empty actual +' + 2: a1bbb7e06e5 = 2: f01f4eb011b merge-ort: do check `parse_tree()`'s return value 3: be1dadf2850 ! 3: e82fdf7fbcb t4301: verify that merge-tree fails on missing blob objects @@ t/t4301-merge-tree-write-tree.sh: test_expect_success 'error out on missing tree ' +test_expect_success 'error out on missing blob objects' ' -+ seq1=$(test_seq 1 10 | git hash-object -w --stdin) && -+ seq2=$(test_seq 1 11 | git hash-object -w --stdin) && -+ seq3=$(test_seq 0 10 | git hash-object -w --stdin) && -+ tree1=$(printf "100644 blob %s\tsequence" $seq1 | git mktree) && -+ tree2=$(printf "100644 blob %s\tsequence" $seq2 | git mktree) && -+ tree3=$(printf "100644 blob %s\tsequence" $seq3 | git mktree) && ++ echo 1 | git hash-object -w --stdin >blob1 && ++ echo 2 | git hash-object -w --stdin >blob2 && ++ echo 3 | git hash-object -w --stdin >blob3 && ++ printf "100644 blob $(cat blob1)\tblob\n" | git mktree >tree1 && ++ printf "100644 blob $(cat blob2)\tblob\n" | git mktree >tree2 && ++ printf "100644 blob $(cat blob3)\tblob\n" | git mktree >tree3 && + git init --bare missing-blob.git && -+ test_write_lines $seq1 $seq3 $tree1 $tree2 $tree3 | ++ cat blob1 blob3 tree1 tree2 tree3 | + git pack-objects missing-blob.git/objects/pack/side1-whatever-is-missing && -+ test_must_fail git --git-dir=missing-blob.git merge-tree --merge-base=$tree1 $tree2 $tree3 >actual && ++ test_must_fail git --git-dir=missing-blob.git >actual 2>err \ ++ merge-tree --merge-base=$(cat tree1) $(cat tree2) $(cat tree3) && ++ test_grep "unable to read blob object $(cat blob2)" err && + test_must_be_empty actual +' + 4: ffd38ad602a = 4: 9e4dc94ef03 Always check `parse_tree*()`'s return value 5: 43c04749513 = 5: 91dc4ccd04e cache-tree: avoid an unnecessary check -- gitgitgadget
