@matheusbsbs / matheus-bagliano / commits / a33806398a

merge: make sparse-aware with ORT

Allow 'git merge' to operate without expanding a sparse index, at least not immediately. The index still will be expanded in a few cases: 1. If the merge strategy is 'recursive', then we enable command_requires_full_index at the start of the merge_recursive() method. We expect sparse-index users to also have the 'ort' strategy enabled. 2. With the 'ort' strategy, if the merge results in a conflicted file, then we expand the index before updating the working tree. The loop that iterates over the worktree replaces index entries and tracks 'origintal_cache_nr' which can become completely wrong if the index expands in the middle of the operation. This safety valve is important before that loop starts. A later change will focus this to only expand if we indeed have a conflict outside of the sparse-checkout cone. 3. Other merge strategies are executed as a 'git merge-X' subcommand, and those strategies are currently protected with the 'command_requires_full_index' guard. Some test updates are required, including a mistaken 'git checkout -b' that did not specify the base branch, causing merges to be fast-forward merges. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Derrick Stolee committed Sep 8, 2021 at 11:23 UTC a33806398a418289388ad992e385a314b4b10225

4 files changed +24 -2

builtin/merge.c

@@ -1276,6 +1276,9 @@ int cmd_merge(int argc, const char **argv, const char *prefix)

1276 if (argc == 2 && !strcmp(argv[1], "-h"))

1277 usage_with_options(builtin_merge_usage, builtin_merge_options);

1278

1279 + prepare_repo_settings(the_repository);

1280 + the_repository->settings.command_requires_full_index = 0;

1281 +

1282 /*

1283 * Check if we are _not_ on a detached HEAD, i.e. if there is a

1284 * current branch.

merge-ort.c

@@ -4058,6 +4058,14 @@ static int record_conflicted_index_entries(struct merge_options *opt)

4058 if (strmap_empty(&opt->priv->conflicted))

4059 return 0;

4060

4061 + /*

4062 + * We are in a conflicted state. These conflicts might be inside

4063 + * sparse-directory entries, so expand the index preemptively.

4064 + * Also, we set original_cache_nr below, but that might change if

4065 + * index_name_pos() calls ask for paths within sparse directories.

4066 + */

4067 + ensure_full_index(index);

4068 +

4069 /* If any entries have skip_worktree set, we'll have to check 'em out */

4070 state.force = 1;

4071 state.quiet = 1;

merge-recursive.c

@@ -3750,6 +3750,9 @@ int merge_recursive(struct merge_options *opt,

3750 assert(opt->ancestor == NULL ||

3751 !strcmp(opt->ancestor, "constructed merge base"));

3752

3753 + prepare_repo_settings(opt->repo);

3754 + opt->repo->settings.command_requires_full_index = 1;

3755 +

3756 if (merge_start(opt, repo_get_commit_tree(opt->repo, h1)))

3757 return -1;

3758 clean = merge_recursive_internal(opt, h1, h2, merge_bases, result);

t/t1092-sparse-checkout-compatibility.sh

+10 -2

@@ -47,7 +47,7 @@ test_expect_success 'setup' '

47 git checkout -b base &&

48 for dir in folder1 folder2 deep

49 do

50 - git checkout -b update-$dir &&

50 + git checkout -b update-$dir base &&

51 echo "updated $dir" >$dir/a &&

52 git commit -a -m "update $dir" || return 1

53 done &&

@@ -647,7 +647,15 @@ test_expect_success 'sparse-index is not expanded' '

647 echo >>sparse-index/extra.txt &&

648 ensure_not_expanded add extra.txt &&

649 echo >>sparse-index/untracked.txt &&

650 - ensure_not_expanded add .

650 + ensure_not_expanded add . &&

651 +

652 + ensure_not_expanded checkout -f update-deep &&

653 + test_config -C sparse-index pull.twohead ort &&

654 + (

655 + sane_unset GIT_TEST_MERGE_ALGORITHM &&

656 + ensure_not_expanded merge -m merge update-folder1 &&

657 + ensure_not_expanded merge -m merge update-folder2

658 + )

659 '

660

661 # NEEDSWORK: a sparse-checkout behaves differently from a full checkout