From: Sam Bostock via GitGitGadget Date: Fri, 06 Feb 2026 19:16:21 GMT Subject: [PATCH v2 0/2] merge-ours: sparse-index integration Message-ID: In-Reply-To: This short series teaches merge-ours to work with a sparse index as a small step toward broader sparse-index support. Patch 1 is a preparatory cleanup that converts merge-ours away from the_repository global, using the repo parameter instead. Patch 2 adds the actual sparse-index integration and tests. Changes since v1: * Patch 1: note in commit message that RUN_SETUP guarantees repo is never NULL (Patrick, Junio) * Patch 2: rewrite commit message to follow the project's standard log message structure (Junio) Thanks Junio and Patrick for the review. Developed with AI assistance (Claude). Sam Bostock (2): merge-ours: drop USE_THE_REPOSITORY_VARIABLE merge-ours: integrate with sparse-index builtin/merge-ours.c | 15 +++++++++------ t/t1092-sparse-checkout-compatibility.sh | 14 ++++++++++++++ 2 files changed, 23 insertions(+), 6 deletions(-) base-commit: b2826b52eb7caff9f4ed6e85ec45e338bf02ad09 Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-2189%2Fsambostock%2Fsb%2Fmerge-ours-sparse-index-v2 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-2189/sambostock/sb/merge-ours-sparse-index-v2 Pull-Request: https://github.com/git/git/pull/2189 Range-diff vs v1: 1: 6cb970e512 ! 1: 775d76df69 merge-ours: drop USE_THE_REPOSITORY_VARIABLE @@ Metadata ## Commit message ## merge-ours: drop USE_THE_REPOSITORY_VARIABLE - Use the `repo` parameter passed to cmd_merge_ours() instead of - `the_repository`, and drop the USE_THE_REPOSITORY_VARIABLE macro that - is no longer needed. + The merge-ours built-in uses the `the_repository` global to access + the repository. The project is moving away from this global in favor + of the `repo` parameter that is passed to each built-in command. + Since merge-ours is registered with RUN_SETUP, `repo` is guaranteed + to be non-NULL and can be used directly. + + Drop the USE_THE_REPOSITORY_VARIABLE macro and use `repo` throughout. While at it, remove a stray double blank line between the #include block and the usage string. 2: 20b9e0bf6e ! 2: 55d39ff778 merge-ours: integrate with sparse-index @@ Metadata ## Commit message ## merge-ours: integrate with sparse-index - The merge-ours builtin reads the index only to compare it against HEAD - via index_differs_from(), whose diff machinery (run_diff_index) is - already sparse-aware. + The merge-ours built-in opens the index to compare it against HEAD. + The machinery used to do this (i.e. run_diff_index()) is capable of + working with a sparse index, but the start-up sequence of this + command does not take the necessary steps, so we end up expanding the + index fully before doing the comparison. - Teach merge-ours to opt out of requiring a full index by setting - command_requires_full_index to 0. Because merge-ours is invoked as a - subprocess by "git merge -s ours" and never previously read config, - the global variables core_apply_sparse_checkout and - core_sparse_checkout_cone remained unset, causing - is_sparse_index_allowed() to return false and the index to be expanded - anyway. Add a repo_config() call with git_default_config to populate - these globals. + In order to convince sparse-index.c:is_sparse_index_allowed() to + return true, we need to: - Add tests to t1092 verifying that "git merge -s ours" produces - identical results across full-checkout, sparse-checkout, and - sparse-index modes, including verifying the resulting merge commit - structure, and that the sparse index is not expanded during the - operation. + - Read basic configuration with git_default_config so that global + variables like core_apply_sparse_checkout are populated. + merge-ours currently does not read configuration at all. + + - Set command_requires_full_index to 0. + + With that, the command can work without expanding the index fully + before doing its work. Signed-off-by: Sam Bostock -- gitgitgadget