Sparse Index: Integrate with merge, cherry-pick, rebase, and revert

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.

builtin/rebase.c

@@ -559,6 +559,9 @@ int cmd_rebase__interactive(int argc, const char **argv, const char *prefix)
 	argc = parse_options(argc, argv, prefix, options,
 			builtin_rebase_interactive_usage, PARSE_OPT_KEEP_ARGV0);
 
+	prepare_repo_settings(the_repository);
+	the_repository->settings.command_requires_full_index = 0;
+
 	if (!is_null_oid(&squash_onto))
 		opts.squash_onto = &squash_onto;
 
@@ -1430,6 +1433,9 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		usage_with_options(builtin_rebase_usage,
 				   builtin_rebase_options);
 
+	prepare_repo_settings(the_repository);
+	the_repository->settings.command_requires_full_index = 0;
+
 	options.allow_empty_message = 1;
 	git_config(rebase_config, &options);
 	/* options.gpg_sign_opt will be either "-S" or NULL */

builtin/revert.c

@@ -136,6 +136,9 @@ static int run_sequencer(int argc, const char **argv, struct replay_opts *opts)
 			PARSE_OPT_KEEP_ARGV0 |
 			PARSE_OPT_KEEP_UNKNOWN);
 
+	prepare_repo_settings(the_repository);
+	the_repository->settings.command_requires_full_index = 0;
+
 	/* implies allow_empty */
 	if (opts->keep_redundant_commits)
 		opts->allow_empty = 1;

diff.c

@@ -26,6 +26,7 @@
 #include "parse-options.h"
 #include "help.h"
 #include "promisor-remote.h"
+#include "dir.h"
 
 #ifdef NO_FAST_WORKING_DIRECTORY
 #define FAST_WORKING_DIRECTORY 0
@@ -3907,6 +3908,13 @@ static int reuse_worktree_file(struct index_state *istate,
 	if (!want_file && would_convert_to_git(istate, name))
 		return 0;
 
+	/*
+	 * If this path does not match our sparse-checkout definition,
+	 * then the file will not be in the working directory.
+	 */
+	if (!path_in_sparse_checkout(name, istate))
+		return 0;
+
 	len = strlen(name);
 	pos = index_name_pos(istate, name, len);
 	if (pos < 0)

merge-ort.c

@@ -4058,6 +4058,21 @@ 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 check if any entries are outside
+	 * of the sparse-checkout cone preemptively.
+	 *
+	 * We set original_cache_nr below, but that might change if
+	 * index_name_pos() calls ask for paths within sparse directories.
+	 */
+	strmap_for_each_entry(&opt->priv->conflicted, &iter, e) {
+		if (!path_in_sparse_checkout(e->key, index)) {
+			ensure_full_index(index);
+			break;
+		}
+	}
+
 	/* If any entries have skip_worktree set, we'll have to check 'em out */
 	state.force = 1;
 	state.quiet = 1;

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);

sequencer.c

@@ -652,6 +652,7 @@ static int do_recursive_merge(struct repository *r,
 		merge_switch_to_result(&o, head_tree, &result, 1, show_output);
 		clean = result.clean;
 	} else {
+		ensure_full_index(r->index);
 		clean = merge_trees(&o, head_tree, next_tree, base_tree);
 		if (is_rebase_i(opts) && clean <= 0)
 			fputs(o.obuf.buf, stdout);
@@ -2346,13 +2347,21 @@ static int read_and_refresh_cache(struct repository *r,
 			_(action_name(opts)));
 	}
 	refresh_index(r->index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
+
 	if (index_fd >= 0) {
 		if (write_locked_index(r->index, &index_lock,
 				       COMMIT_LOCK | SKIP_IF_UNCHANGED)) {
 			return error(_("git %s: failed to refresh the index"),
 				_(action_name(opts)));
 		}
 	}
+
+	/*
+	 * If we are resolving merges in any way other than "ort", then
+	 * expand the sparse index.
+	 */
+	if (opts->strategy && strcmp(opts->strategy, "ort"))
+		ensure_full_index(r->index);
 	return 0;
 }
 

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 &&
@@ -481,14 +481,17 @@ test_expect_success 'checkout and reset (mixed) [sparse]' '
 	test_sparse_match git reset update-folder2
 '
 
-test_expect_success 'merge' '
+test_expect_success 'merge, cherry-pick, and rebase' '
 	init_repos &&
 
-	test_all_match git checkout -b merge update-deep &&
-	test_all_match git merge -m "folder1" update-folder1 &&
-	test_all_match git rev-parse HEAD^{tree} &&
-	test_all_match git merge -m "folder2" update-folder2 &&
-	test_all_match git rev-parse HEAD^{tree}
+	for OPERATION in "merge -m merge" cherry-pick rebase
+	do
+		test_all_match git checkout -B temp update-deep &&
+		test_all_match git $OPERATION update-folder1 &&
+		test_all_match git rev-parse HEAD^{tree} &&
+		test_all_match git $OPERATION update-folder2 &&
+		test_all_match git rev-parse HEAD^{tree} || return 1
+	done
 '
 
 # NEEDSWORK: This test is documenting current behavior, but that
@@ -524,6 +527,38 @@ test_expect_success 'merge with conflict outside cone' '
 	test_all_match git rev-parse HEAD^{tree}
 '
 
+test_expect_success 'cherry-pick/rebase with conflict outside cone' '
+	init_repos &&
+
+	for OPERATION in cherry-pick rebase
+	do
+		test_all_match git checkout -B tip &&
+		test_all_match git reset --hard merge-left &&
+		test_all_match git status --porcelain=v2 &&
+		test_all_match test_must_fail git $OPERATION merge-right &&
+		test_all_match git status --porcelain=v2 &&
+
+		# Resolve the conflict in different ways:
+		# 1. Revert to the base
+		test_all_match git checkout base -- deep/deeper2/a &&
+		test_all_match git status --porcelain=v2 &&
+
+		# 2. Add the file with conflict markers
+		test_all_match git add folder1/a &&
+		test_all_match git status --porcelain=v2 &&
+
+		# 3. Rename the file to another sparse filename and
+		#    accept conflict markers as resolved content.
+		run_on_all mv folder2/a folder2/z &&
+		test_all_match git add folder2 &&
+		test_all_match git status --porcelain=v2 &&
+
+		test_all_match git $OPERATION --continue &&
+		test_all_match git status --porcelain=v2 &&
+		test_all_match git rev-parse HEAD^{tree} || return 1
+	done
+'
+
 test_expect_success 'merge with outside renames' '
 	init_repos &&
 
@@ -617,8 +652,17 @@ test_expect_success 'sparse-index is expanded and converted back' '
 ensure_not_expanded () {
 	rm -f trace2.txt &&
 	echo >>sparse-index/untracked.txt &&
-	GIT_TRACE2_EVENT="$(pwd)/trace2.txt" GIT_TRACE2_EVENT_NESTING=10 \
-		git -C sparse-index "$@" &&
+
+	if test "$1" = "!"
+	then
+		shift &&
+		test_must_fail env \
+			GIT_TRACE2_EVENT="$(pwd)/trace2.txt" GIT_TRACE2_EVENT_NESTING=10 \
+			git -C sparse-index "$@" || return 1
+	else
+		GIT_TRACE2_EVENT="$(pwd)/trace2.txt" GIT_TRACE2_EVENT_NESTING=10 \
+			git -C sparse-index "$@" || return 1
+	fi &&
 	test_region ! index ensure_full_index trace2.txt
 }
 
@@ -647,7 +691,35 @@ 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 &&
+	test_config -C sparse-index pull.twohead ort &&
+	(
+		sane_unset GIT_TEST_MERGE_ALGORITHM &&
+		for OPERATION in "merge -m merge" cherry-pick rebase
+		do
+			ensure_not_expanded merge -m merge update-folder1 &&
+			ensure_not_expanded merge -m merge update-folder2 || return 1
+		done
+	)
+'
+
+test_expect_success 'sparse-index is not expanded: merge conflict in cone' '
+	init_repos &&
+
+	for side in right left
+	do
+		git -C sparse-index checkout -b expand-$side base &&
+		echo $side >sparse-index/deep/a &&
+		git -C sparse-index commit -a -m "$side" || return 1
+	done &&
+
+	(
+		sane_unset GIT_TEST_MERGE_ALGORITHM &&
+		git -C sparse-index config pull.twohead ort &&
+		ensure_not_expanded ! merge -m merged expand-right
+	)
 '
 
 # NEEDSWORK: a sparse-checkout behaves differently from a full checkout