[PATCH 0/4] merge-tree: handle missing objects correctly

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 js/merge-tree-3-trees because I introduced three unchecked parse_tree() calls in that topic branch.

Johannes Schindelin (4):
  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

 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 | 24 ++++++++++++++++++++++++
 13 files changed, 84 insertions(+), 15 deletions(-)

base-commit: 5f43cf5b2e4b68386d3774bce880b0f74d801635
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1651%2Fdscho%2Fmerge-tree-and-missing-objects-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1651/dscho/merge-tree-and-missing-objects-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/1651