COM0 is a valid path, although Windows Explorer does not allow to create this

src/path.c

@@ -1254,7 +1254,7 @@ GIT_INLINE(bool) verify_dospath(
 	if (len < last || git__strncasecmp(component, dospath, 3) != 0)
 		return true;
 
-	if (trailing_num && !git__isdigit(component[3]))
+	if (trailing_num && (component[3] < '1' || component[3] > '9'))
 		return true;
 
 	return (len > last &&

tests/path/core.c

@@ -233,6 +233,8 @@ void test_path_core__isvalid_dos_paths_withnum(void)
 	cl_assert_equal_b(false, git_path_isvalid(NULL, "com1.asdf\\zippy", GIT_PATH_REJECT_DOS_PATHS));
 	cl_assert_equal_b(false, git_path_isvalid(NULL, "com1:asdf\\foobar", GIT_PATH_REJECT_DOS_PATHS));
 
+	cl_assert_equal_b(true, git_path_isvalid(NULL, "com0", 0));
+	cl_assert_equal_b(true, git_path_isvalid(NULL, "com0", GIT_PATH_REJECT_DOS_PATHS));
 	cl_assert_equal_b(true, git_path_isvalid(NULL, "com10", 0));
 	cl_assert_equal_b(true, git_path_isvalid(NULL, "com10", GIT_PATH_REJECT_DOS_PATHS));
 	cl_assert_equal_b(true, git_path_isvalid(NULL, "comn", GIT_PATH_REJECT_DOS_PATHS));