On Tue, Aug 24, 2021 at 2:52 PM Derrick Stolee via GitGitGadget <gitgitgadget@xxxxxxxxx> wrote: > > From: Derrick Stolee <dstolee@xxxxxxxxxxxxx> > > 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. > > 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@xxxxxxxxxxxxx> > --- > 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. > + * 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?
