[PATCH 00/13] [RFC] Sparse-checkout: modify 'git add', 'git rm', and 'git add' behavior

@@ -291,6 +291,18 @@ test_expect_success 'add, commit, checkout' '
 	test_all_match git checkout -
 '
 
+# NEEDSWORK: This documents current behavior, but is not a desirable
+# behavior (untracked files are handled differently than tracked).
+test_expect_success 'add outside sparse cone' '
+	init_repos &&
+
+	run_on_sparse mkdir folder1 &&
+	run_on_sparse ../edit-contents folder1/a &&
+	run_on_sparse ../edit-contents folder1/newfile &&
+	test_sparse_match test_must_fail git add folder1/a &&
+	test_sparse_match git add folder1/newfile
+'
+
 test_expect_success 'commit including unstaged changes' '
 	init_repos &&
 

@@ -1303,6 +1303,19 @@ int match_pathname(const char *pathname, int pathlen,
 				 WM_PATHNAME) == 0;
 }
 
+static int path_matches_dir_pattern(const char *pathname,
+				    int pathlen,
+				    int *dtype,
+				    struct path_pattern *pattern,
+				    struct index_state *istate)
+{
+	*dtype = resolve_dtype(*dtype, istate, pathname, pathlen);
+	if (*dtype != DT_DIR)
+		return 0;
+
+	return 1;
+}
+
 /*
  * Scan the given exclude list in reverse to see whether pathname
  * should be ignored.  The first match (i.e. the last on the list), if

@@ -1327,11 +1340,10 @@ static struct path_pattern *last_matching_pattern_from_list(const char *pathname
 		const char *exclude = pattern->pattern;
 		int prefix = pattern->nowildcardlen;
 
-		if (pattern->flags & PATTERN_FLAG_MUSTBEDIR) {
-			*dtype = resolve_dtype(*dtype, istate, pathname, pathlen);
-			if (*dtype != DT_DIR)
-				continue;
-		}
+		if ((pattern->flags & PATTERN_FLAG_MUSTBEDIR) &&
+		    !path_matches_dir_pattern(pathname, pathlen,
+					      dtype, pattern, istate))
+			continue;
 
 		if (pattern->flags & PATTERN_FLAG_NODIR) {
 			if (match_basename(basename,

@@ -1305,10 +1305,38 @@ int match_pathname(const char *pathname, int pathlen,
 
 static int path_matches_dir_pattern(const char *pathname,
 				    int pathlen,
+				    struct strbuf *path_parent,
 				    int *dtype,
 				    struct path_pattern *pattern,
 				    struct index_state *istate)
 {
+	/*
+	 * Use 'alloc' as an indicator that the string has not been
+	 * initialized, in case the parent is the root directory.
+	 */
+	if (!path_parent->alloc) {
+		char *slash;
+		strbuf_addstr(path_parent, pathname);
+		slash = find_last_dir_sep(path_parent->buf);
+
+		if (slash)
+			*slash = '\0';
+		else
+			strbuf_setlen(path_parent, 0);
+	}
+
+	/*
+	 * If the parent directory matches the pattern, then we do not
+	 * need to check for dtype.
+	 */
+	if (path_parent->len &&
+	    match_pathname(path_parent->buf, path_parent->len,
+			   pattern->base,
+			   pattern->baselen ? pattern->baselen - 1 : 0,
+			   pattern->pattern, pattern->nowildcardlen,
+			   pattern->patternlen, pattern->flags))
+		return 1;
+
 	*dtype = resolve_dtype(*dtype, istate, pathname, pathlen);
 	if (*dtype != DT_DIR)
 		return 0;

@@ -1331,6 +1359,7 @@ static struct path_pattern *last_matching_pattern_from_list(const char *pathname
 {
 	struct path_pattern *res = NULL; /* undecided */
 	int i;
+	struct strbuf path_parent = STRBUF_INIT;
 
 	if (!pl->nr)
 		return NULL;	/* undefined */

@@ -1340,8 +1369,8 @@ static struct path_pattern *last_matching_pattern_from_list(const char *pathname
 		const char *exclude = pattern->pattern;
 		int prefix = pattern->nowildcardlen;
 
-		if ((pattern->flags & PATTERN_FLAG_MUSTBEDIR) &&
-		    !path_matches_dir_pattern(pathname, pathlen,
+		if (pattern->flags & PATTERN_FLAG_MUSTBEDIR &&
+		    !path_matches_dir_pattern(pathname, pathlen, &path_parent,
 					      dtype, pattern, istate))
 			continue;
 

@@ -1367,6 +1396,7 @@ static struct path_pattern *last_matching_pattern_from_list(const char *pathname
 			break;
 		}
 	}
+	strbuf_release(&path_parent);
 	return res;
 }
 

@@ -1294,7 +1294,7 @@ int match_pathname(const char *pathname, int pathlen,
 		 * then our prefix match is all we need; we
 		 * do not need to call fnmatch at all.
 		 */
-		if (!patternlen && !namelen)
+		if (!patternlen && (!namelen || (flags & PATTERN_FLAG_MUSTBEDIR)))
 			return 1;
 	}
 

@@ -443,6 +443,7 @@ static void check_embedded_repo(const char *path)
 static int add_files(struct dir_struct *dir, int flags)
 {
 	int i, exit_status = 0;
+	struct string_list only_match_skip_worktree = STRING_LIST_INIT_NODUP;
 
 	if (dir->ignored_nr) {
 		fprintf(stderr, _(ignore_error));

@@ -456,6 +457,11 @@ static int add_files(struct dir_struct *dir, int flags)
 	}
 
 	for (i = 0; i < dir->nr; i++) {
+		if (!path_in_sparse_checkout(dir->entries[i]->name, &the_index)) {
+			string_list_append(&only_match_skip_worktree,
+					   dir->entries[i]->name);
+			continue;
+		}
 		if (add_file_to_index(&the_index, dir->entries[i]->name, flags)) {
 			if (!ignore_add_errors)
 				die(_("adding files failed"));

@@ -464,6 +470,14 @@ static int add_files(struct dir_struct *dir, int flags)
 			check_embedded_repo(dir->entries[i]->name);
 		}
 	}
+
+	if (only_match_skip_worktree.nr) {
+		advise_on_updating_sparse_paths(&only_match_skip_worktree);
+		exit_status = 1;
+	}
+
+	string_list_clear(&only_match_skip_worktree, 0);
+
 	return exit_status;
 }
 

@@ -291,8 +291,6 @@ test_expect_success 'add, commit, checkout' '
 	test_all_match git checkout -
 '
 
-# NEEDSWORK: This documents current behavior, but is not a desirable
-# behavior (untracked files are handled differently than tracked).
 test_expect_success 'add outside sparse cone' '
 	init_repos &&
 

@@ -300,7 +298,7 @@ test_expect_success 'add outside sparse cone' '
 	run_on_sparse ../edit-contents folder1/a &&
 	run_on_sparse ../edit-contents folder1/newfile &&
 	test_sparse_match test_must_fail git add folder1/a &&
-	test_sparse_match git add folder1/newfile
+	test_sparse_match test_must_fail git add folder1/newfile
 '
 
 test_expect_success 'commit including unstaged changes' '

@@ -331,7 +329,11 @@ test_expect_success 'commit including unstaged changes' '
 	test_all_match git status --porcelain=v2
 '
 
-test_expect_success 'status/add: outside sparse cone' '
+# NEEDSWORK: Now that 'git add folder1/new' fails, the changes being
+# attempted here fail for the sparse-checkout and sparse-index repos.
+# We must enable a way for adding files outside the sparse-checkout
+# done, even if it is by an optional flag.
+test_expect_failure 'status/add: outside sparse cone' '
 	init_repos &&
 
 	# folder1 is at HEAD, but outside the sparse cone

@@ -352,10 +354,9 @@ test_expect_success 'status/add: outside sparse cone' '
 	# Adding the path outside of the sparse-checkout cone should fail.
 	test_sparse_match test_must_fail git add folder1/a &&
 	test_sparse_match test_must_fail git add --refresh folder1/a &&
+	test_sparse_match test_must_fail git add folder1/new &&
 
-	# NEEDSWORK: Adding a newly-tracked file outside the cone succeeds
-	test_sparse_match git add folder1/new &&
-
+	# NEEDSWORK: behavior begins to deviate here.
 	test_all_match git add . &&
 	test_all_match git status --porcelain=v2 &&
 	test_all_match git commit -m folder1/new &&

@@ -511,7 +512,7 @@ test_expect_success 'merge, cherry-pick, and rebase' '
 # Right now, users might be using this flow to work through conflicts,
 # so any solution should present advice to users who try this sequence
 # of commands to follow whatever new method we create.
-test_expect_success 'merge with conflict outside cone' '
+test_expect_failure 'merge with conflict outside cone' '
 	init_repos &&
 
 	test_all_match git checkout -b merge-tip merge-left &&

@@ -525,12 +526,18 @@ test_expect_success 'merge with conflict outside cone' '
 	test_all_match git status --porcelain=v2 &&
 
 	# 2. Add the file with conflict markers
+	# NEEDSWORK: Even though the merge conflict removed the
+	# SKIP_WORKTREE bit from the index entry for folder1/a, we should
+	# warn that this is a problematic add.
 	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 &&
+	# NEEDSWORK: This mode now fails, because folder2/z is
+	# outside of the sparse-checkout cone and does not match an
+	# existing index entry with the SKIP_WORKTREE bit cleared.
 	test_all_match git add folder2 &&
 	test_all_match git status --porcelain=v2 &&
 

@@ -539,7 +546,7 @@ 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' '
+test_expect_failure 'cherry-pick/rebase with conflict outside cone' '
 	init_repos &&
 
 	for OPERATION in cherry-pick rebase

@@ -556,11 +563,17 @@ test_expect_success 'cherry-pick/rebase with conflict outside cone' '
 		test_all_match git status --porcelain=v2 &&
 
 		# 2. Add the file with conflict markers
+		# NEEDSWORK: Even though the merge conflict removed the
+		# SKIP_WORKTREE bit from the index entry for folder1/a, we should
+		# warn that this is a problematic add.
 		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.
+		# NEEDSWORK: This mode now fails, because folder2/z is
+		# outside of the sparse-checkout cone and does not match an
+		# existing index entry with the SKIP_WORKTREE bit cleared.
 		run_on_all mv folder2/a folder2/z &&
 		test_all_match git add folder2 &&
 		test_all_match git status --porcelain=v2 &&

@@ -638,6 +651,7 @@ test_expect_success 'clean' '
 test_expect_success 'submodule handling' '
 	init_repos &&
 
+	test_sparse_match git sparse-checkout add modules &&
 	test_all_match mkdir modules &&
 	test_all_match touch modules/a &&
 	test_all_match git add modules &&

@@ -647,6 +661,7 @@ test_expect_success 'submodule handling' '
 	test_all_match git commit -m "add submodule" &&
 
 	# having a submodule prevents "modules" from collapse
+	test_sparse_match git sparse-checkout set deep/deeper1 &&
 	test-tool -C sparse-index read-cache --table >cache &&
 	grep "100644 blob .*	modules/a" cache &&
 	grep "160000 commit $(git -C initial-repo rev-parse HEAD)	modules/sub" cache

@@ -39,7 +39,8 @@ void add_pathspec_matches_against_index(const struct pathspec *pathspec,
 		return;
 	for (i = 0; i < istate->cache_nr; i++) {
 		const struct cache_entry *ce = istate->cache[i];
-		if (sw_action == PS_IGNORE_SKIP_WORKTREE && ce_skip_worktree(ce))
+		if (sw_action == PS_IGNORE_SKIP_WORKTREE &&
+		    (ce_skip_worktree(ce) || !path_in_sparse_checkout(ce->name, istate)))
 			continue;
 		ce_path_match(istate, ce, pathspec, seen);
 	}

@@ -529,7 +529,7 @@ test_expect_failure 'merge with conflict outside cone' '
 	# NEEDSWORK: Even though the merge conflict removed the
 	# SKIP_WORKTREE bit from the index entry for folder1/a, we should
 	# warn that this is a problematic add.
-	test_all_match git add folder1/a &&
+	test_sparse_match test_must_fail git add folder1/a &&
 	test_all_match git status --porcelain=v2 &&
 
 	# 3. Rename the file to another sparse filename and

@@ -538,7 +538,7 @@ test_expect_failure 'merge with conflict outside cone' '
 	# NEEDSWORK: This mode now fails, because folder2/z is
 	# outside of the sparse-checkout cone and does not match an
 	# existing index entry with the SKIP_WORKTREE bit cleared.
-	test_all_match git add folder2 &&
+	test_sparse_match test_must_fail git add folder2 &&
 	test_all_match git status --porcelain=v2 &&
 
 	test_all_match git merge --continue &&

@@ -566,7 +566,7 @@ test_expect_failure 'cherry-pick/rebase with conflict outside cone' '
 		# NEEDSWORK: Even though the merge conflict removed the
 		# SKIP_WORKTREE bit from the index entry for folder1/a, we should
 		# warn that this is a problematic add.
-		test_all_match git add folder1/a &&
+		test_sparse_match test_must_fail git add folder1/a &&
 		test_all_match git status --porcelain=v2 &&
 
 		# 3. Rename the file to another sparse filename and

@@ -575,7 +575,7 @@ test_expect_failure 'cherry-pick/rebase with conflict outside cone' '
 		# outside of the sparse-checkout cone and does not match an
 		# existing index entry with the SKIP_WORKTREE bit cleared.
 		run_on_all mv folder2/a folder2/z &&
-		test_all_match git add folder2 &&
+		test_sparse_match test_must_fail git add folder2 &&
 		test_all_match git status --porcelain=v2 &&
 
 		test_all_match git $OPERATION --continue &&

@@ -9,7 +9,7 @@ SYNOPSIS
 --------
 [verse]
 'git add' [--verbose | -v] [--dry-run | -n] [--force | -f] [--interactive | -i] [--patch | -p]
-	  [--edit | -e] [--[no-]all | --[no-]ignore-removal | [--update | -u]]
+	  [--edit | -e] [--[no-]all | --[no-]ignore-removal | [--update | -u]] [--sparse]
 	  [--intent-to-add | -N] [--refresh] [--ignore-errors] [--ignore-missing] [--renormalize]
 	  [--chmod=(+|-)x] [--pathspec-from-file=<file> [--pathspec-file-nul]]
 	  [--] [<pathspec>...]

@@ -79,6 +79,13 @@ in linkgit:gitglossary[7].
 --force::
 	Allow adding otherwise ignored files.
 
+--sparse::
+	Allow updating index entries outside of the sparse-checkout cone.
+	Normally, `git add` refuses to update index entries whose paths do
+	not fit within the sparse-checkout cone, since those files might
+	be removed from the working tree without warning. See
+	linkgit:git-sparse-checkout[1] for more.
+
 -i::
 --interactive::
 	Add modified contents in the working tree interactively to

@@ -30,6 +30,7 @@ static int patch_interactive, add_interactive, edit_interactive;
 static int take_worktree_changes;
 static int add_renormalize;
 static int pathspec_file_nul;
+static int include_sparse;
 static const char *pathspec_from_file;
 static int legacy_stash_p; /* support for the scripted `git stash` */
 

@@ -46,7 +47,7 @@ static int chmod_pathspec(struct pathspec *pathspec, char flip, int show_only)
 		struct cache_entry *ce = active_cache[i];
 		int err;
 
-		if (ce_skip_worktree(ce))
+		if (!include_sparse && ce_skip_worktree(ce))
 			continue;
 
 		if (pathspec && !ce_path_match(&the_index, ce, pathspec, NULL))

@@ -379,6 +380,7 @@ static struct option builtin_add_options[] = {
 	OPT_BOOL( 0 , "refresh", &refresh_only, N_("don't add, only refresh the index")),
 	OPT_BOOL( 0 , "ignore-errors", &ignore_add_errors, N_("just skip files which cannot be added because of errors")),
 	OPT_BOOL( 0 , "ignore-missing", &ignore_missing, N_("check if - even missing - files are ignored in dry run")),
+	OPT_BOOL(0, "sparse", &include_sparse, N_("allow updating entries outside of the sparse-checkout cone")),
 	OPT_STRING(0, "chmod", &chmod_arg, "(+|-)x",
 		   N_("override the executable bit of the listed files")),
 	OPT_HIDDEN_BOOL(0, "warn-embedded-repo", &warn_on_embedded_repo,

@@ -457,7 +459,8 @@ static int add_files(struct dir_struct *dir, int flags)
 	}
 
 	for (i = 0; i < dir->nr; i++) {
-		if (!path_in_sparse_checkout(dir->entries[i]->name, &the_index)) {
+		if (!include_sparse &&
+		    !path_in_sparse_checkout(dir->entries[i]->name, &the_index)) {
 			string_list_append(&only_match_skip_worktree,
 					   dir->entries[i]->name);
 			continue;

@@ -642,7 +645,8 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 			if (seen[i])
 				continue;
 
-			if (matches_skip_worktree(&pathspec, i, &skip_worktree_seen)) {
+			if (!include_sparse &&
+			    matches_skip_worktree(&pathspec, i, &skip_worktree_seen)) {
 				string_list_append(&only_match_skip_worktree,
 						   pathspec.items[i].original);
 				continue;

@@ -329,11 +329,7 @@ test_expect_success 'commit including unstaged changes' '
 	test_all_match git status --porcelain=v2
 '
 
-# NEEDSWORK: Now that 'git add folder1/new' fails, the changes being
-# attempted here fail for the sparse-checkout and sparse-index repos.
-# We must enable a way for adding files outside the sparse-checkout
-# done, even if it is by an optional flag.
-test_expect_failure 'status/add: outside sparse cone' '
+test_expect_success 'status/add: outside sparse cone' '
 	init_repos &&
 
 	# folder1 is at HEAD, but outside the sparse cone

@@ -355,15 +351,16 @@ test_expect_failure 'status/add: outside sparse cone' '
 	test_sparse_match test_must_fail git add folder1/a &&
 	test_sparse_match test_must_fail git add --refresh folder1/a &&
 	test_sparse_match test_must_fail git add folder1/new &&
+	test_sparse_match git add --sparse folder1/a &&
+	test_sparse_match git add --sparse folder1/new &&
 
-	# NEEDSWORK: behavior begins to deviate here.
-	test_all_match git add . &&
+	test_all_match git add --sparse . &&
 	test_all_match git status --porcelain=v2 &&
 	test_all_match git commit -m folder1/new &&
 	test_all_match git rev-parse HEAD^{tree} &&
 
 	run_on_all ../edit-contents folder1/newer &&
-	test_all_match git add folder1/ &&
+	test_all_match git add --sparse folder1/ &&
 	test_all_match git status --porcelain=v2 &&
 	test_all_match git commit -m folder1/newer &&
 	test_all_match git rev-parse HEAD^{tree}

@@ -507,12 +504,7 @@ test_expect_success 'merge, cherry-pick, and rebase' '
 	done
 '
 
-# NEEDSWORK: This test is documenting current behavior, but that
-# behavior can be confusing to users so there is desire to change it.
-# Right now, users might be using this flow to work through conflicts,
-# so any solution should present advice to users who try this sequence
-# of commands to follow whatever new method we create.
-test_expect_failure 'merge with conflict outside cone' '
+test_expect_success 'merge with conflict outside cone' '
 	init_repos &&
 
 	test_all_match git checkout -b merge-tip merge-left &&

@@ -528,17 +520,15 @@ test_expect_failure 'merge with conflict outside cone' '
 	# 2. Add the file with conflict markers
 	# NEEDSWORK: Even though the merge conflict removed the
 	# SKIP_WORKTREE bit from the index entry for folder1/a, we should
-	# warn that this is a problematic add.
-	test_sparse_match test_must_fail git add folder1/a &&
+	# warn that this is a problematic add when --sparse is not set.
+	test_all_match git add --sparse 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 &&
-	# NEEDSWORK: This mode now fails, because folder2/z is
-	# outside of the sparse-checkout cone and does not match an
-	# existing index entry with the SKIP_WORKTREE bit cleared.
 	test_sparse_match test_must_fail git add folder2 &&
+	test_all_match git add --sparse folder2 &&
 	test_all_match git status --porcelain=v2 &&
 
 	test_all_match git merge --continue &&

@@ -152,4 +152,12 @@ test_expect_success 'add obeys advice.updateSparsePath' '
 
 '
 
+test_expect_success 'add allows sparse entries with --sparse' '
+	git sparse-checkout set a &&
+	echo modified >sparse_entry &&
+	test_must_fail git add sparse_entry &&
+	git add --sparse sparse_entry 2>stderr &&
+	test_must_be_empty stderr
+'
+
 test_done

@@ -71,7 +71,7 @@ char *find_pathspecs_matching_skip_worktree(const struct pathspec *pathspec)
 
 	for (i = 0; i < istate->cache_nr; i++) {
 		struct cache_entry *ce = istate->cache[i];
-		if (ce_skip_worktree(ce))
+		if (ce_skip_worktree(ce) || !path_in_sparse_checkout(ce->name, istate))
 		    ce_path_match(istate, ce, pathspec, seen);
 	}
 

@@ -406,7 +406,7 @@ test_expect_success 'sparse-checkout (init|set|disable) warns with unmerged stat
 	git -C unmerged sparse-checkout disable
 '
 
-test_expect_success 'sparse-checkout reapply' '
+test_expect_failure 'sparse-checkout reapply' '
 	git clone repo tweak &&
 
 	echo dirty >tweak/deep/deeper2/a &&

@@ -438,6 +438,8 @@ test_expect_success 'sparse-checkout reapply' '
 	test_i18ngrep "warning.*The following paths are unmerged" err &&
 	test_path_is_file tweak/folder1/a &&
 
+	# NEEDSWORK: We are asking to update a file outside of the
+	# sparse-checkout cone, but this is no longer allowed.
 	git -C tweak add folder1/a &&
 	git -C tweak sparse-checkout reapply 2>err &&
 	test_must_be_empty err &&

@@ -518,9 +518,8 @@ test_expect_success 'merge with conflict outside cone' '
 	test_all_match git status --porcelain=v2 &&
 
 	# 2. Add the file with conflict markers
-	# NEEDSWORK: Even though the merge conflict removed the
-	# SKIP_WORKTREE bit from the index entry for folder1/a, we should
-	# warn that this is a problematic add when --sparse is not set.
+	test_sparse_match test_must_fail git add folder1/a &&
+	test_i18ngrep "Disable or modify the sparsity rules" sparse-checkout-err &&
 	test_all_match git add --sparse folder1/a &&
 	test_all_match git status --porcelain=v2 &&
 

@@ -528,6 +527,7 @@ test_expect_success 'merge with conflict outside cone' '
 	#    accept conflict markers as resolved content.
 	run_on_all mv folder2/a folder2/z &&
 	test_sparse_match test_must_fail git add folder2 &&
+	test_i18ngrep "Disable or modify the sparsity rules" sparse-checkout-err &&
 	test_all_match git add --sparse folder2 &&
 	test_all_match git status --porcelain=v2 &&
 

@@ -72,6 +72,12 @@ For more details, see the 'pathspec' entry in linkgit:gitglossary[7].
 --ignore-unmatch::
 	Exit with a zero status even if no files matched.
 
+--sparse::
+	Allow updating index entries outside of the sparse-checkout cone.
+	Normally, `git rm` refuses to update index entries whose paths do
+	not fit within the sparse-checkout cone. See
+	linkgit:git-sparse-checkout[1] for more.
+
 -q::
 --quiet::
 	`git rm` normally outputs one line (in the form of an `rm` command)

@@ -237,6 +237,7 @@ static int check_local_mod(struct object_id *head, int index_only)
 
 static int show_only = 0, force = 0, index_only = 0, recursive = 0, quiet = 0;
 static int ignore_unmatch = 0, pathspec_file_nul;
+static int include_sparse;
 static char *pathspec_from_file;
 
 static struct option builtin_rm_options[] = {

@@ -247,6 +248,7 @@ static struct option builtin_rm_options[] = {
 	OPT_BOOL('r', NULL,             &recursive,  N_("allow recursive removal")),
 	OPT_BOOL( 0 , "ignore-unmatch", &ignore_unmatch,
 				N_("exit with a zero status even if nothing matched")),
+	OPT_BOOL(0, "sparse", &include_sparse, N_("allow updating entries outside of the sparse-checkout cone")),
 	OPT_PATHSPEC_FROM_FILE(&pathspec_from_file),
 	OPT_PATHSPEC_FILE_NUL(&pathspec_file_nul),
 	OPT_END(),

@@ -298,7 +300,8 @@ int cmd_rm(int argc, const char **argv, const char *prefix)
 	ensure_full_index(&the_index);
 	for (i = 0; i < active_nr; i++) {
 		const struct cache_entry *ce = active_cache[i];
-		if (ce_skip_worktree(ce))
+
+		if (!include_sparse && ce_skip_worktree(ce))
 			continue;
 		if (!ce_path_match(&the_index, ce, &pathspec, seen))
 			continue;

@@ -322,7 +325,8 @@ int cmd_rm(int argc, const char **argv, const char *prefix)
 				seen_any = 1;
 			else if (ignore_unmatch)
 				continue;
-			else if (matches_skip_worktree(&pathspec, i, &skip_worktree_seen))
+			else if (!include_sparse &&
+				 matches_skip_worktree(&pathspec, i, &skip_worktree_seen))
 				string_list_append(&only_match_skip_worktree, original);
 			else
 				die(_("pathspec '%s' did not match any files"), original);

@@ -36,13 +36,25 @@ done
 
 test_expect_success 'recursive rm does not remove sparse entries' '
 	git reset --hard &&
-	git sparse-checkout set sub/dir &&
+	git sparse-checkout set sub/dir/ &&
 	git rm -r sub &&
 	git status --porcelain -uno >actual &&
 	echo "D  sub/dir/e" >expected &&
 	test_cmp expected actual
 '
 
+test_expect_success 'recursive rm --sparse removes sparse entries' '
+	git reset --hard &&
+	git sparse-checkout set "sub/dir" &&
+	git rm --sparse -r sub &&
+	git status --porcelain -uno >actual &&
+	cat >expected <<-\EOF &&
+	D  sub/d
+	D  sub/dir/e
+	EOF
+	test_cmp expected actual
+'
+
 test_expect_success 'rm obeys advice.updateSparsePath' '
 	git reset --hard &&
 	git sparse-checkout set a &&

@@ -301,7 +301,9 @@ int cmd_rm(int argc, const char **argv, const char *prefix)
 	for (i = 0; i < active_nr; i++) {
 		const struct cache_entry *ce = active_cache[i];
 
-		if (!include_sparse && ce_skip_worktree(ce))
+		if (!include_sparse &&
+		    (ce_skip_worktree(ce) ||
+		     !path_in_sparse_checkout(ce->name, &the_index)))
 			continue;
 		if (!ce_path_match(&the_index, ce, &pathspec, seen))
 			continue;

@@ -87,4 +87,15 @@ test_expect_success 'do not warn about sparse entries with --ignore-unmatch' '
 	git ls-files --error-unmatch b
 '
 
+test_expect_success 'refuse to rm a non-skip-worktree path outside sparse cone' '
+	git reset --hard &&
+	git sparse-checkout set a &&
+	git update-index --no-skip-worktree b &&
+	test_must_fail git rm b 2>stderr &&
+	test_cmp b_error_and_hint stderr &&
+	git rm --sparse b 2>stderr &&
+	test_must_be_empty stderr &&
+	test_path_is_missing b
+'
+
 test_done

@@ -133,6 +133,7 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 	struct string_list src_for_dst = STRING_LIST_INIT_NODUP;
 	struct lock_file lock_file = LOCK_INIT;
 	struct cache_entry *ce;
+	struct string_list only_match_skip_worktree = STRING_LIST_INIT_NODUP;
 
 	git_config(git_default_config, NULL);
 

@@ -176,10 +177,22 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 		const char *src = source[i], *dst = destination[i];
 		int length, src_is_dir;
 		const char *bad = NULL;
+		int skip_sparse = 0;
 
 		if (show_only)
 			printf(_("Checking rename of '%s' to '%s'\n"), src, dst);
 
+		if (!path_in_sparse_checkout(src, &the_index)) {
+			string_list_append(&only_match_skip_worktree, src);
+			skip_sparse = 1;
+		}
+		if (!path_in_sparse_checkout(dst, &the_index)) {
+			string_list_append(&only_match_skip_worktree, dst);
+			skip_sparse = 1;
+		}
+		if (skip_sparse)
+			continue;
+
 		length = strlen(src);
 		if (lstat(src, &st) < 0)
 			bad = _("bad source");

@@ -266,6 +279,12 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 		}
 	}
 
+	if (only_match_skip_worktree.nr) {
+		advise_on_updating_sparse_paths(&only_match_skip_worktree);
+		if (!ignore_errors)
+			return 1;
+	}
+
 	for (i = 0; i < argc; i++) {
 		const char *src = source[i], *dst = destination[i];
 		enum update_mode mode = modes[i];

@@ -0,0 +1,99 @@
+#!/bin/sh
+
+test_description='git mv in sparse working trees'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' "
+	mkdir -p sub/dir sub/dir2 &&
+	touch a b c sub/d sub/dir/e sub/dir2/e &&
+	git add -A &&
+	git commit -m files &&
+
+	cat >sparse_error_header <<-EOF &&
+	The following pathspecs didn't match any eligible path, but they do match index
+	entries outside the current sparse checkout:
+	EOF
+
+	cat >sparse_hint <<-EOF
+	hint: Disable or modify the sparsity rules if you intend to update such entries.
+	hint: Disable this message with \"git config advice.updateSparsePath false\"
+	EOF
+"
+
+test_expect_success 'mv refuses to move sparse-to-sparse' '
+	rm -f e &&
+	git reset --hard &&
+	git sparse-checkout set a &&
+	touch b &&
+	test_must_fail git mv b e 2>stderr &&
+	cat sparse_error_header >expect &&
+	echo b >>expect &&
+	echo e >>expect &&
+	cat sparse_hint >>expect &&
+	test_cmp expect stderr
+'
+
+test_expect_success 'mv refuses to move sparse-to-sparse, ignores failure' '
+	rm -f e &&
+	git reset --hard &&
+	git sparse-checkout set a &&
+	touch b &&
+	git mv -k b e 2>stderr &&
+	cat sparse_error_header >expect &&
+	echo b >>expect &&
+	echo e >>expect &&
+	cat sparse_hint >>expect &&
+	test_cmp expect stderr
+'
+
+test_expect_success 'mv refuses to move non-sparse-to-sparse' '
+	rm -f e &&
+	git reset --hard &&
+	git sparse-checkout set a &&
+	test_must_fail git mv a e 2>stderr &&
+	cat sparse_error_header >expect &&
+	echo e >>expect &&
+	cat sparse_hint >>expect &&
+	test_cmp expect stderr
+'
+
+test_expect_success 'mv refuses to move sparse-to-non-sparse' '
+	rm -f e &&
+	git reset --hard &&
+	git sparse-checkout set a e &&
+	touch b &&
+	test_must_fail git mv b e 2>stderr &&
+	cat sparse_error_header >expect &&
+	echo b >>expect &&
+	cat sparse_hint >>expect &&
+	test_cmp expect stderr
+'
+
+test_expect_success 'recursive mv refuses to move (possible) sparse' '
+	rm -f e &&
+	git reset --hard &&
+	# Without cone mode, "sub" and "sub2" do not match
+	git sparse-checkout set sub/dir sub2/dir &&
+	test_must_fail git mv sub sub2 2>stderr &&
+	cat sparse_error_header >expect &&
+	echo sub >>expect &&
+	echo sub2 >>expect &&
+	cat sparse_hint >>expect &&
+	test_cmp expect stderr
+'
+
+test_expect_success 'recursive mv refuses to move sparse' '
+	git reset --hard &&
+	# Use cone mode so "sub/" matches the sparse-checkout patterns
+	git sparse-checkout init --cone &&
+	git sparse-checkout set sub/dir sub2/dir &&
+	test_must_fail git mv sub sub2 2>stderr &&
+	cat sparse_error_header >expect &&
+	echo sub/dir2/e >>expect &&
+	echo sub2/dir2/e >>expect &&
+	cat sparse_hint >>expect &&
+	test_cmp expect stderr
+'
+
+test_done

@@ -118,17 +118,18 @@ static int index_range_of_same_dir(const char *src, int length,
 int cmd_mv(int argc, const char **argv, const char *prefix)
 {
 	int i, flags, gitmodules_modified = 0;
-	int verbose = 0, show_only = 0, force = 0, ignore_errors = 0;
+	int verbose = 0, show_only = 0, force = 0, ignore_errors = 0, ignore_sparse = 0;
 	struct option builtin_mv_options[] = {
 		OPT__VERBOSE(&verbose, N_("be verbose")),
 		OPT__DRY_RUN(&show_only, N_("dry run")),
 		OPT__FORCE(&force, N_("force move/rename even if target exists"),
 			   PARSE_OPT_NOCOMPLETE),
 		OPT_BOOL('k', NULL, &ignore_errors, N_("skip move/rename errors")),
+		OPT_BOOL(0, "sparse", &ignore_sparse, N_("allow updating entries outside of the sparse-checkout cone")),
 		OPT_END(),
 	};
 	const char **source, **destination, **dest_path, **submodule_gitfile;
-	enum update_mode { BOTH = 0, WORKING_DIRECTORY, INDEX } *modes;
+	enum update_mode { BOTH = 0, WORKING_DIRECTORY, INDEX, SPARSE } *modes;
 	struct stat st;
 	struct string_list src_for_dst = STRING_LIST_INIT_NODUP;
 	struct lock_file lock_file = LOCK_INIT;

@@ -182,11 +183,11 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 		if (show_only)
 			printf(_("Checking rename of '%s' to '%s'\n"), src, dst);
 
-		if (!path_in_sparse_checkout(src, &the_index)) {
+		if (!ignore_sparse && !path_in_sparse_checkout(src, &the_index)) {
 			string_list_append(&only_match_skip_worktree, src);
 			skip_sparse = 1;
 		}
-		if (!path_in_sparse_checkout(dst, &the_index)) {
+		if (!ignore_sparse && !path_in_sparse_checkout(dst, &the_index)) {
 			string_list_append(&only_match_skip_worktree, dst);
 			skip_sparse = 1;
 		}

@@ -194,9 +195,11 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 			continue;
 
 		length = strlen(src);
-		if (lstat(src, &st) < 0)
-			bad = _("bad source");
-		else if (!strncmp(src, dst, length) &&
+		if (lstat(src, &st) < 0) {
+			/* only error if existence is expected. */
+			if (modes[i] != SPARSE)
+				bad = _("bad source");
+		} else if (!strncmp(src, dst, length) &&
 				(dst[length] == 0 || dst[length] == '/')) {
 			bad = _("can not move directory into itself");
 		} else if ((src_is_dir = S_ISDIR(st.st_mode))

@@ -225,11 +228,12 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 				dst_len = strlen(dst);
 
 				for (j = 0; j < last - first; j++) {
-					const char *path = active_cache[first + j]->name;
+					const struct cache_entry *ce = active_cache[first + j];
+					const char *path = ce->name;
 					source[argc + j] = path;
 					destination[argc + j] =
 						prefix_path(dst, dst_len, path + length + 1);
-					modes[argc + j] = INDEX;
+					modes[argc + j] = ce_skip_worktree(ce) ? SPARSE : INDEX;
 					submodule_gitfile[argc + j] = NULL;
 				}
 				argc += last - first;

@@ -293,7 +297,7 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 			printf(_("Renaming %s to %s\n"), src, dst);
 		if (show_only)
 			continue;
-		if (mode != INDEX && rename(src, dst) < 0) {
+		if (mode != INDEX && mode != SPARSE && rename(src, dst) < 0) {
 			if (ignore_errors)
 				continue;
 			die_errno(_("renaming '%s' failed"), src);

@@ -31,7 +31,9 @@ test_expect_success 'mv refuses to move sparse-to-sparse' '
 	echo b >>expect &&
 	echo e >>expect &&
 	cat sparse_hint >>expect &&
-	test_cmp expect stderr
+	test_cmp expect stderr &&
+	git mv --sparse b e 2>stderr &&
+	test_must_be_empty stderr
 '
 
 test_expect_success 'mv refuses to move sparse-to-sparse, ignores failure' '

@@ -44,7 +46,9 @@ test_expect_success 'mv refuses to move sparse-to-sparse, ignores failure' '
 	echo b >>expect &&
 	echo e >>expect &&
 	cat sparse_hint >>expect &&
-	test_cmp expect stderr
+	test_cmp expect stderr &&
+	git mv --sparse -k b e 2>stderr &&
+	test_must_be_empty stderr
 '
 
 test_expect_success 'mv refuses to move non-sparse-to-sparse' '

@@ -55,7 +59,9 @@ test_expect_success 'mv refuses to move non-sparse-to-sparse' '
 	cat sparse_error_header >expect &&
 	echo e >>expect &&
 	cat sparse_hint >>expect &&
-	test_cmp expect stderr
+	test_cmp expect stderr &&
+	git mv --sparse a e 2>stderr &&
+	test_must_be_empty stderr
 '
 
 test_expect_success 'mv refuses to move sparse-to-non-sparse' '

@@ -67,7 +73,9 @@ test_expect_success 'mv refuses to move sparse-to-non-sparse' '
 	cat sparse_error_header >expect &&
 	echo b >>expect &&
 	cat sparse_hint >>expect &&
-	test_cmp expect stderr
+	test_cmp expect stderr &&
+	git mv --sparse b e 2>stderr &&
+	test_must_be_empty stderr
 '
 
 test_expect_success 'recursive mv refuses to move (possible) sparse' '

@@ -80,7 +88,14 @@ test_expect_success 'recursive mv refuses to move (possible) sparse' '
 	echo sub >>expect &&
 	echo sub2 >>expect &&
 	cat sparse_hint >>expect &&
-	test_cmp expect stderr
+	test_cmp expect stderr &&
+	git mv --sparse sub sub2 2>stderr &&
+	test_must_be_empty stderr &&
+	git commit -m "moved sub to sub2" &&
+	git rev-parse HEAD~1:sub >expect &&
+	git rev-parse HEAD:sub2 >actual &&
+	test_cmp expect actual &&
+	git reset --hard HEAD~1
 '
 
 test_expect_success 'recursive mv refuses to move sparse' '

@@ -93,7 +108,14 @@ test_expect_success 'recursive mv refuses to move sparse' '
 	echo sub/dir2/e >>expect &&
 	echo sub2/dir2/e >>expect &&
 	cat sparse_hint >>expect &&
-	test_cmp expect stderr
+	test_cmp expect stderr &&
+	git mv --sparse sub sub2 2>stderr &&
+	test_must_be_empty stderr &&
+	git commit -m "moved sub to sub2" &&
+	git rev-parse HEAD~1:sub >expect &&
+	git rev-parse HEAD:sub2 >actual &&
+	test_cmp expect actual &&
+	git reset --hard HEAD~1
 '
 
 test_done

@@ -300,7 +300,8 @@ void advise_on_updating_sparse_paths(struct string_list *pathspec_list)
 		fprintf(stderr, "%s\n", item->string);
 
 	advise_if_enabled(ADVICE_UPDATE_SPARSE_PATH,
-			  _("Disable or modify the sparsity rules if you intend"
+			  _("Disable or modify the sparsity rules or"
+			    " use the --sparse option if you intend"
 			    " to update such entries."));
 }
 

@@ -16,7 +16,7 @@ test_expect_success 'setup' "
 	EOF
 
 	cat >sparse_hint <<-EOF &&
-	hint: Disable or modify the sparsity rules if you intend to update such entries.
+	hint: Disable or modify the sparsity rules or use the --sparse option if you intend to update such entries.
 	hint: Disable this message with \"git config advice.updateSparsePath false\"
 	EOF
 

@@ -43,7 +43,7 @@ test_expect_success 'setup' "
 	EOF
 
 	cat >sparse_hint <<-EOF &&
-	hint: Disable or modify the sparsity rules if you intend to update such entries.
+	hint: Disable or modify the sparsity rules or use the --sparse option if you intend to update such entries.
 	hint: Disable this message with \"git config advice.updateSparsePath false\"
 	EOF
 

@@ -16,7 +16,7 @@ test_expect_success 'setup' "
 	EOF
 
 	cat >sparse_hint <<-EOF
-	hint: Disable or modify the sparsity rules if you intend to update such entries.
+	hint: Disable or modify the sparsity rules or use the --sparse option if you intend to update such entries.
 	hint: Disable this message with \"git config advice.updateSparsePath false\"
 	EOF
 "

@@ -198,7 +198,8 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 				continue;
 		}
 
-		if (ce_uptodate(ce) || ce_skip_worktree(ce))
+		if (ce_uptodate(ce) || ce_skip_worktree(ce) ||
+		    !path_in_sparse_checkout(ce->name, istate))
 			continue;
 
 		/*

@@ -94,6 +94,10 @@ static void update_callback(struct diff_queue_struct *q,
 	for (i = 0; i < q->nr; i++) {
 		struct diff_filepair *p = q->queue[i];
 		const char *path = p->one->path;
+
+		if (!path_in_sparse_checkout(path, &the_index))
+			continue;
+
 		switch (fix_unmerged_status(p, data)) {
 		default:
 			die(_("unexpected diff status %c"), p->status);