Re: [PATCH v2 2/6] merge: make sparse-aware with ORT
flat view
From: Elijah Newren <hidden>
Date: 2021-08-27 22:43:13
On Tue, Aug 24, 2021 at 2:52 PM Derrick Stolee via GitGitGadget [off-list ref] wrote:
From: Derrick Stolee <redacted> 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.
Oh, indeed, it appears ag/merge-strategies-in-c didn't complete but was discarded, as per the July 6 "What's cooking in git.git" email. Well, that certainly makes things easier for you; thanks for mentioning them in this item #3.
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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 <redacted> --- builtin/merge.c | 3 +++ merge-ort.c | 8 ++++++++ merge-recursive.c | 3 +++ t/t1092-sparse-checkout-compatibility.sh | 12 ++++++++++-- 4 files changed, 24 insertions(+), 2 deletions(-)diff --git a/builtin/merge.c b/builtin/merge.c index 22f23990b37..926de328fbb 100644 --- a/builtin/merge.c +++ b/builtin/merge.c@@ -1276,6 +1276,9 @@ int cmd_merge(int argc, const char **argv, const char *prefix) if (argc == 2 && !strcmp(argv[1], "-h")) usage_with_options(builtin_merge_usage, builtin_merge_options); + prepare_repo_settings(the_repository); + the_repository->settings.command_requires_full_index = 0; + /* * Check if we are _not_ on a detached HEAD, i.e. if there is a * current branch.diff --git a/merge-ort.c b/merge-ort.c index 6eb910d6f0c..8e754b769e1 100644 --- a/merge-ort.c +++ b/merge-ort.c@@ -4058,6 +4058,14 @@ static int record_conflicted_index_entries(struct merge_options *opt) if (strmap_empty(&opt->priv->conflicted)) return 0; + /* + * We are in a conflicted state. These conflicts might be inside + * sparse-directory entries, so expand the index preemtively.
Same typo I pointed out in v1.
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+ * Also, we set original_cache_nr below, but that might change if + * index_name_pos() calls ask for paths within sparse directories. + */ + ensure_full_index(index); + /* If any entries have skip_worktree set, we'll have to check 'em out */ state.force = 1; state.quiet = 1;diff --git a/merge-recursive.c b/merge-recursive.c index 3355d50e8ad..1f563cd6874 100644 --- a/merge-recursive.c +++ b/merge-recursive.c@@ -3750,6 +3750,9 @@ int merge_recursive(struct merge_options *opt, assert(opt->ancestor == NULL || !strcmp(opt->ancestor, "constructed merge base")); + prepare_repo_settings(opt->repo); + opt->repo->settings.command_requires_full_index = 1; + if (merge_start(opt, repo_get_commit_tree(opt->repo, h1))) return -1; clean = merge_recursive_internal(opt, h1, h2, merge_bases, result);diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh index ddc86bb4152..dc56252865c 100755 --- a/t/t1092-sparse-checkout-compatibility.sh +++ b/t/t1092-sparse-checkout-compatibility.sh@@ -47,7 +47,7 @@ test_expect_success 'setup' ' git checkout -b base && for dir in folder1 folder2 deep do - git checkout -b update-$dir && + git checkout -b update-$dir base && echo "updated $dir" >$dir/a && git commit -a -m "update $dir" || return 1 done &&@@ -647,7 +647,15 @@ test_expect_success 'sparse-index is not expanded' ' echo >>sparse-index/extra.txt && ensure_not_expanded add extra.txt && echo >>sparse-index/untracked.txt && - ensure_not_expanded add . + ensure_not_expanded add . && + + ensure_not_expanded checkout -f update-deep && + ( + sane_unset GIT_TEST_MERGE_ALGORITHM && + git -C sparse-index config pull.twohead ort && + ensure_not_expanded merge -m merge update-folder1 && + ensure_not_expanded merge -m merge update-folder2 + ) '
Should you use test_config rather than git config here? More importantly, why the subshell and unsetting of GIT_TEST_MERGE_ALGORITHM and the special worrying about pull.twohead? Wouldn't it be simpler to just set GIT_TEST_MERGE_ALGORITHM=ort, perhaps at the beginning of the file?