[PATCH 12/13] mv: add '--sparse' option to ignore sparse-checkout

["Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com>]

From: Derrick Stolee <dstolee@microsoft.com>

Users can get into strange situations if 'git mv' allows moving files
into, out of, or around the sparse-checkout cone. However, some users
may still want to do it. Allow knowledgeable users to do so via a new
'--sparse' option.

There are some special cases that occur in this change, such as the case
of a directory that doesn't match the sparse-checkout cone, but exists
in the working tree because a subset of its contents do match. We need
to communicate that index entries with the SKIP_WORKTREE bit are not
expected to be in the working directory and hence are not needed when
moving the contents. This is only a check for the existence of the
source file. The call to rename_cache_entry_at() still changes the index
appropriately in these cases.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 builtin/mv.c                  | 24 ++++++++++++++----------
 t/t7002-mv-sparse-checkout.sh | 34 ++++++++++++++++++++++++++++------
 2 files changed, 42 insertions(+), 16 deletions(-)

diff --git a/builtin/mv.c b/builtin/mv.c
index b58fd4ce5ba..92ea9f0ca37 100644
--- a/builtin/mv.c
+++ b/builtin/mv.c
@@ -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);
diff --git a/t/t7002-mv-sparse-checkout.sh b/t/t7002-mv-sparse-checkout.sh
index 5397c6d07bd..517fd587fa8 100755
--- a/t/t7002-mv-sparse-checkout.sh
+++ b/t/t7002-mv-sparse-checkout.sh
@@ -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
-- 
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