Sync with 2.21.1

* maint-2.21: (42 commits)
  Git 2.21.1
  mingw: sh arguments need quoting in more circumstances
  mingw: fix quoting of empty arguments for `sh`
  mingw: use MSYS2 quoting even when spawning shell scripts
  mingw: detect when MSYS2's sh is to be spawned more robustly
  t7415: drop v2.20.x-specific work-around
  Git 2.20.2
  t7415: adjust test for dubiously-nested submodule gitdirs for v2.20.x
  Git 2.19.3
  Git 2.18.2
  Git 2.17.3
  Git 2.16.6
  test-drop-caches: use `has_dos_drive_prefix()`
  Git 2.15.4
  Git 2.14.6
  mingw: handle `subst`-ed "DOS drives"
  mingw: refuse to access paths with trailing spaces or periods
  mingw: refuse to access paths with illegal characters
  unpack-trees: let merged_entry() pass through do_add_entry()'s errors
  quote-stress-test: offer to test quoting arguments for MSYS2 sh
  ...

2 files changed, 19 insertions, 3 deletions

diff --git a/builtin/clone.c b/builtin/clone.c
index 3623f040d4..6b285111d5 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -777,7 +777,7 @@ static int checkout(int submodule_progress)
 
 	if (!err && (option_recurse_submodules.nr > 0)) {
 		struct argv_array args = ARGV_ARRAY_INIT;
-		argv_array_pushl(&args, "submodule", "update", "--init", "--recursive", NULL);
+		argv_array_pushl(&args, "submodule", "update", "--require-init", "--recursive", NULL);
 
 		if (option_shallow_submodules == 1)
 			argv_array_push(&args, "--depth=1");
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index afaf0819c9..f9264c0621 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -19,6 +19,7 @@
 #include "diffcore.h"
 #include "diff.h"
 #include "object-store.h"
+#include "dir.h"
 
 #define OPT_QUIET (1 << 0)
 #define OPT_CACHED (1 << 1)
@@ -1359,7 +1360,7 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 	char *p, *path = NULL, *sm_gitdir;
 	struct strbuf sb = STRBUF_INIT;
 	struct string_list reference = STRING_LIST_INIT_NODUP;
-	int dissociate = 0;
+	int dissociate = 0, require_init = 0;
 	char *sm_alternate = NULL, *error_strategy = NULL;
 
 	struct option module_clone_options[] = {
@@ -1386,6 +1387,8 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 		OPT__QUIET(&quiet, "Suppress output for cloning a submodule"),
 		OPT_BOOL(0, "progress", &progress,
 			   N_("force cloning progress")),
+		OPT_BOOL(0, "require-init", &require_init,
+			   N_("disallow cloning into non-empty directory")),
 		OPT_END()
 	};
 
@@ -1413,6 +1416,10 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 	} else
 		path = xstrdup(path);
 
+	if (validate_submodule_git_dir(sm_gitdir, name) < 0)
+		die(_("refusing to create/use '%s' in another submodule's "
+			"git dir"), sm_gitdir);
+
 	if (!file_exists(sm_gitdir)) {
 		if (safe_create_leading_directories_const(sm_gitdir) < 0)
 			die(_("could not create directory '%s'"), sm_gitdir);
@@ -1424,6 +1431,8 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 			die(_("clone of '%s' into submodule path '%s' failed"),
 			    url, path);
 	} else {
+		if (require_init && !access(path, X_OK) && !is_empty_dir(path))
+			die(_("directory not empty: '%s'"), path);
 		if (safe_create_leading_directories_const(path) < 0)
 			die(_("could not create directory '%s'"), path);
 		strbuf_addf(&sb, "%s/index", sm_gitdir);
@@ -1478,6 +1487,8 @@ static void determine_submodule_update_strategy(struct repository *r,
 			die(_("Invalid update mode '%s' configured for submodule path '%s'"),
 				val, path);
 	} else if (sub->update_strategy.type != SM_UPDATE_UNSPECIFIED) {
+		if (sub->update_strategy.type == SM_UPDATE_COMMAND)
+			BUG("how did we read update = !command from .gitmodules?");
 		out->type = sub->update_strategy.type;
 		out->command = sub->update_strategy.command;
 	} else
@@ -1536,6 +1547,7 @@ struct submodule_update_clone {
 	int recommend_shallow;
 	struct string_list references;
 	int dissociate;
+	unsigned require_init;
 	const char *depth;
 	const char *recursive_prefix;
 	const char *prefix;
@@ -1554,7 +1566,7 @@ struct submodule_update_clone {
 	int max_jobs;
 };
 #define SUBMODULE_UPDATE_CLONE_INIT {0, MODULE_LIST_INIT, 0, \
-	SUBMODULE_UPDATE_STRATEGY_INIT, 0, 0, -1, STRING_LIST_INIT_DUP, 0, \
+	SUBMODULE_UPDATE_STRATEGY_INIT, 0, 0, -1, STRING_LIST_INIT_DUP, 0, 0, \
 	NULL, NULL, NULL, \
 	NULL, 0, 0, 0, NULL, 0, 0, 1}
 
@@ -1681,6 +1693,8 @@ static int prepare_to_clone_next_submodule(const struct cache_entry *ce,
 		argv_array_pushl(&child->args, "--prefix", suc->prefix, NULL);
 	if (suc->recommend_shallow && sub->recommend_shallow == 1)
 		argv_array_push(&child->args, "--depth=1");
+	if (suc->require_init)
+		argv_array_push(&child->args, "--require-init");
 	argv_array_pushl(&child->args, "--path", sub->path, NULL);
 	argv_array_pushl(&child->args, "--name", sub->name, NULL);
 	argv_array_pushl(&child->args, "--url", url, NULL);
@@ -1870,6 +1884,8 @@ static int update_clone(int argc, const char **argv, const char *prefix)
 		OPT__QUIET(&suc.quiet, N_("don't print cloning progress")),
 		OPT_BOOL(0, "progress", &suc.progress,
 			    N_("force cloning progress")),
+		OPT_BOOL(0, "require-init", &suc.require_init,
+			   N_("disallow cloning into non-empty directory")),
 		OPT_END()
 	};