Check input mesh is valid in SurfaceTool methods

(cherry picked from commit 0ad0f71ba0d564a8383197ef2febb45d3506758f)

scene/resources/surface_tool.cpp

@@ -526,7 +526,7 @@ void SurfaceTool::deindex() {
 }
 
 void SurfaceTool::_create_list(const Ref<Mesh> &p_existing, int p_surface, List<Vertex> *r_vertex, List<int> *r_index, int &lformat) {
-
+	ERR_FAIL_COND_MSG(p_existing.is_null(), "First argument in SurfaceTool::_create_list() must be a valid object of type Mesh");
 	Array arr = p_existing->surface_get_arrays(p_surface);
 	ERR_FAIL_COND(arr.size() != VS::ARRAY_MAX);
 	_create_list_from_arrays(arr, r_vertex, r_index, lformat);
@@ -763,7 +763,7 @@ void SurfaceTool::create_from_triangle_arrays(const Array &p_arrays) {
 }
 
 void SurfaceTool::create_from(const Ref<Mesh> &p_existing, int p_surface) {
-
+	ERR_FAIL_COND_MSG(p_existing.is_null(), "First argument in SurfaceTool::create_from() must be a valid object of type Mesh");
 	clear();
 	primitive = p_existing->surface_get_primitive_type(p_surface);
 	_create_list(p_existing, p_surface, &vertex_array, &index_array, format);
@@ -771,6 +771,7 @@ void SurfaceTool::create_from(const Ref<Mesh> &p_existing, int p_surface) {
 }
 
 void SurfaceTool::create_from_blend_shape(const Ref<Mesh> &p_existing, int p_surface, const String &p_blend_shape_name) {
+	ERR_FAIL_COND_MSG(p_existing.is_null(), "First argument in SurfaceTool::create_from_blend_shape() must be a valid object of type Mesh");
 	clear();
 	primitive = p_existing->surface_get_primitive_type(p_surface);
 	Array arr = p_existing->surface_get_blend_shape_arrays(p_surface);
@@ -791,7 +792,7 @@ void SurfaceTool::create_from_blend_shape(const Ref<Mesh> &p_existing, int p_sur
 }
 
 void SurfaceTool::append_from(const Ref<Mesh> &p_existing, int p_surface, const Transform &p_xform) {
-
+	ERR_FAIL_COND_MSG(p_existing.is_null(), "First argument in SurfaceTool::append_from() must be a valid object of type Mesh");
 	if (vertex_array.size() == 0) {
 		primitive = p_existing->surface_get_primitive_type(p_surface);
 		format = 0;