28 files changed, 183 insertions, 34 deletions
diff --git a/core/SCsub b/core/SCsub
index ed9a0a231d..b12c6a9e27 100644
--- a/core/SCsub
+++ b/core/SCsub
@@ -80,6 +80,8 @@ if env['builtin_zlib']:
 	env_thirdparty.Prepend(CPPPATH=[thirdparty_zlib_dir])
 	# Needs to be available in main env too
 	env.Prepend(CPPPATH=[thirdparty_zlib_dir])
+	if (env['target'] == 'debug'):
+		env_thirdparty.Append(CPPDEFINES=['ZLIB_DEBUG'])
 
 	env_thirdparty.add_source_files(env.core_sources, thirdparty_zlib_sources)
 
diff --git a/core/bind/core_bind.cpp b/core/bind/core_bind.cpp
index d07ba44788..c539f912aa 100644
--- a/core/bind/core_bind.cpp
+++ b/core/bind/core_bind.cpp
@@ -1136,6 +1136,16 @@ bool _OS::request_permission(const String &p_name) {
 	return OS::get_singleton()->request_permission(p_name);
 }
 
+bool _OS::request_permissions() {
+
+	return OS::get_singleton()->request_permissions();
+}
+
+Vector<String> _OS::get_granted_permissions() const {
+
+	return OS::get_singleton()->get_granted_permissions();
+}
+
 _OS *_OS::singleton = NULL;
 
 void _OS::_bind_methods() {
@@ -1319,6 +1329,8 @@ void _OS::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_power_percent_left"), &_OS::get_power_percent_left);
 
 	ClassDB::bind_method(D_METHOD("request_permission", "name"), &_OS::request_permission);
+	ClassDB::bind_method(D_METHOD("request_permissions"), &_OS::request_permissions);
+	ClassDB::bind_method(D_METHOD("get_granted_permissions"), &_OS::get_granted_permissions);
 
 	ADD_PROPERTY(PropertyInfo(Variant::STRING, "clipboard"), "set_clipboard", "get_clipboard");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "current_screen"), "set_current_screen", "get_current_screen");
@@ -3153,6 +3165,9 @@ Ref<JSONParseResult> _JSON::parse(const String &p_json) {
 
 	result->error = JSON::parse(p_json, result->result, result->error_string, result->error_line);
 
+	if (result->error != OK) {
+		ERR_PRINTS(vformat("Error parsing JSON at line %s: %s", result->error_line, result->error_string));
+	}
 	return result;
 }
 
diff --git a/core/bind/core_bind.h b/core/bind/core_bind.h
index 693b85710a..1a4fd1d5cb 100644
--- a/core/bind/core_bind.h
+++ b/core/bind/core_bind.h
@@ -349,6 +349,8 @@ public:
 	bool has_feature(const String &p_feature) const;
 
 	bool request_permission(const String &p_name);
+	bool request_permissions();
+	Vector<String> get_granted_permissions() const;
 
 	static _OS *get_singleton() { return singleton; }
 
diff --git a/core/crypto/hashing_context.cpp b/core/crypto/hashing_context.cpp
index bd863f546b..b5aa0ddc18 100644
--- a/core/crypto/hashing_context.cpp
+++ b/core/crypto/hashing_context.cpp
@@ -50,6 +50,7 @@ Error HashingContext::start(HashType p_type) {
 Error HashingContext::update(PoolByteArray p_chunk) {
 	ERR_FAIL_COND_V(ctx == NULL, ERR_UNCONFIGURED);
 	size_t len = p_chunk.size();
+	ERR_FAIL_COND_V(len == 0, FAILED);
 	PoolByteArray::Read r = p_chunk.read();
 	switch (type) {
 		case HASH_MD5:
diff --git a/core/dictionary.cpp b/core/dictionary.cpp
index 5e4dfb9a5a..0d9945991e 100644
--- a/core/dictionary.cpp
+++ b/core/dictionary.cpp
@@ -192,13 +192,9 @@ uint32_t Dictionary::hash() const {
 
 	uint32_t h = hash_djb2_one_32(Variant::DICTIONARY);
 
-	List<Variant> keys;
-	get_key_list(&keys);
-
-	for (List<Variant>::Element *E = keys.front(); E; E = E->next()) {
-
-		h = hash_djb2_one_32(E->get().hash(), h);
-		h = hash_djb2_one_32(operator[](E->get()).hash(), h);
+	for (OrderedHashMap<Variant, Variant, VariantHasher, VariantComparator>::Element E = _p->variant_map.front(); E; E = E.next()) {
+		h = hash_djb2_one_32(E.key().hash(), h);
+		h = hash_djb2_one_32(E.value().hash(), h);
 	}
 
 	return h;
@@ -207,10 +203,11 @@ uint32_t Dictionary::hash() const {
 Array Dictionary::keys() const {
 
 	Array varr;
-	varr.resize(size());
 	if (_p->variant_map.empty())
 		return varr;
 
+	varr.resize(size());
+
 	int i = 0;
 	for (OrderedHashMap<Variant, Variant, VariantHasher, VariantComparator>::Element E = _p->variant_map.front(); E; E = E.next()) {
 		varr[i] = E.key();
@@ -223,10 +220,11 @@ Array Dictionary::keys() const {
 Array Dictionary::values() const {
 
 	Array varr;
-	varr.resize(size());
 	if (_p->variant_map.empty())
 		return varr;
 
+	varr.resize(size());
+
 	int i = 0;
 	for (OrderedHashMap<Variant, Variant, VariantHasher, VariantComparator>::Element E = _p->variant_map.front(); E; E = E.next()) {
 		varr[i] = E.get();
@@ -255,11 +253,8 @@ Dictionary Dictionary::duplicate(bool p_deep) const {
 
 	Dictionary n;
 
-	List<Variant> keys;
-	get_key_list(&keys);
-
-	for (List<Variant>::Element *E = keys.front(); E; E = E->next()) {
-		n[E->get()] = p_deep ? operator[](E->get()).duplicate(p_deep) : operator[](E->get());
+	for (OrderedHashMap<Variant, Variant, VariantHasher, VariantComparator>::Element E = _p->variant_map.front(); E; E = E.next()) {
+		n[E.key()] = p_deep ? E.value().duplicate(true) : E.value();
 	}
 
 	return n;
diff --git a/core/hash_map.h b/core/hash_map.h
index 38da1d59ab..edc67e7806 100644
--- a/core/hash_map.h
+++ b/core/hash_map.h
@@ -210,6 +210,7 @@ private:
 		e->next = hash_table[index];
 		e->hash = hash;
 		e->pair.key = p_key;
+		e->pair.data = TData();
 
 		hash_table[index] = e;
 		elements++;
diff --git a/core/image.cpp b/core/image.cpp
index e0b0a1f8be..74706535b3 100644
--- a/core/image.cpp
+++ b/core/image.cpp
@@ -885,8 +885,8 @@ void Image::resize(int p_width, int p_height, Interpolation p_interpolation) {
 
 	bool mipmap_aware = p_interpolation == INTERPOLATE_TRILINEAR /* || p_interpolation == INTERPOLATE_TRICUBIC */;
 
-	ERR_FAIL_COND_MSG(p_width <= 0, "Image width cannot be greater than 0.");
-	ERR_FAIL_COND_MSG(p_height <= 0, "Image height cannot be greater than 0.");
+	ERR_FAIL_COND_MSG(p_width <= 0, "Image width must be greater than 0.");
+	ERR_FAIL_COND_MSG(p_height <= 0, "Image height must be greater than 0.");
 	ERR_FAIL_COND_MSG(p_width > MAX_WIDTH, "Image width cannot be greater than " + itos(MAX_WIDTH) + ".");
 	ERR_FAIL_COND_MSG(p_height > MAX_HEIGHT, "Image height cannot be greater than " + itos(MAX_HEIGHT) + ".");
 
@@ -1284,8 +1284,8 @@ static void _generate_po2_mipmap(const Component *p_src, Component *p_dst, uint3
 		Component *dst_ptr = &p_dst[i * dst_w * CC];
 		uint32_t count = dst_w;
 
-		while (count--) {
-
+		while (count) {
+			count--;
 			for (int j = 0; j < CC; j++) {
 				average_func(dst_ptr[j], rup_ptr[j], rup_ptr[j + right_step], rdown_ptr[j], rdown_ptr[j + right_step]);
 			}
@@ -1322,6 +1322,8 @@ void Image::expand_x2_hq2x() {
 		PoolVector<uint8_t>::Read r = data.read();
 		PoolVector<uint8_t>::Write w = dest.write();
 
+		ERR_FAIL_COND(!r.ptr());
+
 		hq2x_resize((const uint32_t *)r.ptr(), width, height, (uint32_t *)w.ptr());
 	}
 
@@ -1373,6 +1375,7 @@ void Image::shrink_x2() {
 		int ps = get_format_pixel_size(format);
 		new_img.resize((width / 2) * (height / 2) * ps);
 		ERR_FAIL_COND(new_img.size() == 0);
+		ERR_FAIL_COND(data.size() == 0);
 
 		{
 			PoolVector<uint8_t>::Write w = new_img.write();
@@ -2895,6 +2898,8 @@ void Image::bumpmap_to_normalmap(float bump_scale) {
 		PoolVector<uint8_t>::Read rp = data.read();
 		PoolVector<uint8_t>::Write wp = result_image.write();
 
+		ERR_FAIL_COND(!rp.ptr());
+
 		unsigned char *write_ptr = wp.ptr();
 		float *read_ptr = (float *)rp.ptr();
 
@@ -2930,7 +2935,7 @@ void Image::srgb_to_linear() {
 	if (data.size() == 0)
 		return;
 
-	static const uint8_t srgb2lin[256] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 10, 11, 11, 11, 12, 12, 13, 13, 13, 14, 14, 15, 15, 16, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21, 22, 22, 23, 23, 24, 24, 25, 26, 26, 27, 27, 28, 29, 29, 30, 31, 31, 32, 33, 33, 34, 35, 36, 36, 37, 38, 38, 39, 40, 41, 42, 42, 43, 44, 45, 46, 47, 47, 48, 49, 50, 51, 52, 53, 54, 55, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 70, 71, 72, 73, 74, 75, 76, 77, 78, 80, 81, 82, 83, 84, 85, 87, 88, 89, 90, 92, 93, 94, 95, 97, 98, 99, 101, 102, 103, 105, 106, 107, 109, 110, 112, 113, 114, 116, 117, 119, 120, 122, 123, 125, 126, 128, 129, 131, 132, 134, 135, 137, 139, 140, 142, 144, 145, 147, 148, 150, 152, 153, 155, 157, 159, 160, 162, 164, 166, 167, 169, 171, 173, 175, 176, 178, 180, 182, 184, 186, 188, 190, 192, 193, 195, 197, 199, 201, 203, 205, 207, 209, 211, 213, 215, 218, 220, 222, 224, 226, 228, 230, 232, 235, 237, 239, 241, 243, 245, 248, 250, 252 };
+	static const uint8_t srgb2lin[256] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 10, 11, 11, 11, 12, 12, 13, 13, 13, 14, 14, 15, 15, 16, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21, 22, 22, 23, 23, 24, 24, 25, 26, 26, 27, 27, 28, 29, 29, 30, 31, 31, 32, 33, 33, 34, 35, 36, 36, 37, 38, 38, 39, 40, 41, 42, 42, 43, 44, 45, 46, 47, 47, 48, 49, 50, 51, 52, 53, 54, 55, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 70, 71, 72, 73, 74, 75, 76, 77, 78, 80, 81, 82, 83, 84, 85, 87, 88, 89, 90, 92, 93, 94, 95, 97, 98, 99, 101, 102, 103, 105, 106, 107, 109, 110, 112, 113, 114, 116, 117, 119, 120, 122, 123, 125, 126, 128, 129, 131, 132, 134, 135, 137, 139, 140, 142, 144, 145, 147, 148, 150, 152, 153, 155, 157, 159, 160, 162, 164, 166, 167, 169, 171, 173, 175, 176, 178, 180, 182, 184, 186, 188, 190, 192, 193, 195, 197, 199, 201, 203, 205, 207, 209, 211, 213, 215, 218, 220, 222, 224, 226, 228, 230, 232, 235, 237, 239, 241, 243, 245, 248, 250, 252, 255 };
 
 	ERR_FAIL_COND(format != FORMAT_RGB8 && format != FORMAT_RGBA8);
 
diff --git a/core/io/multiplayer_api.cpp b/core/io/multiplayer_api.cpp
index 0ba84d0c8f..1426dbbd4d 100644
--- a/core/io/multiplayer_api.cpp
+++ b/core/io/multiplayer_api.cpp
@@ -602,7 +602,16 @@ void MultiplayerAPI::_add_peer(int p_id) {
 
 void MultiplayerAPI::_del_peer(int p_id) {
 	connected_peers.erase(p_id);
-	path_get_cache.erase(p_id); // I no longer need your cache, sorry.
+	// Cleanup get cache.
+	path_get_cache.erase(p_id);
+	// Cleanup sent cache.
+	// Some refactoring is needed to make this faster and do paths GC.
+	List<NodePath> keys;
+	path_send_cache.get_key_list(&keys);
+	for (List<NodePath>::Element *E = keys.front(); E; E = E->next()) {
+		PathSentCache *psc = path_send_cache.getptr(E->get());
+		psc->confirmed_peers.erase(p_id);
+	}
 	emit_signal("network_peer_disconnected", p_id);
 }
 
diff --git a/core/math/math_funcs.h b/core/math/math_funcs.h
index 9078abea68..a94b27fcc5 100644
--- a/core/math/math_funcs.h
+++ b/core/math/math_funcs.h
@@ -472,7 +472,7 @@ public:
 		return p_step != 0 ? Math::stepify(p_target - p_offset, p_step) + p_offset : p_target;
 	}
 
-	static _ALWAYS_INLINE_ float snap_scalar_seperation(float p_offset, float p_step, float p_target, float p_separation) {
+	static _ALWAYS_INLINE_ float snap_scalar_separation(float p_offset, float p_step, float p_target, float p_separation) {
 		if (p_step != 0) {
 			float a = Math::stepify(p_target - p_offset, p_step + p_separation) + p_offset;
 			float b = a;
diff --git a/core/math/plane.cpp b/core/math/plane.cpp
index b01853c4ac..b6bcac4b27 100644
--- a/core/math/plane.cpp
+++ b/core/math/plane.cpp
@@ -91,7 +91,7 @@ bool Plane::intersect_3(const Plane &p_plane1, const Plane &p_plane2, Vector3 *r
 
 	real_t denom = vec3_cross(normal0, normal1).dot(normal2);
 
-	if (ABS(denom) <= CMP_EPSILON)
+	if (Math::is_zero_approx(denom))
 		return false;
 
 	if (r_result) {
diff --git a/core/object.cpp b/core/object.cpp
index 6facf38733..ed3ae4f25d 100644
--- a/core/object.cpp
+++ b/core/object.cpp
@@ -436,7 +436,7 @@ void Object::set(const StringName &p_name, const Variant &p_value, bool *r_valid
 
 	} else if (p_name == CoreStringNames::get_singleton()->_meta) {
 		//set_meta(p_name,p_value);
-		metadata = p_value;
+		metadata = p_value.duplicate();
 		if (r_valid)
 			*r_valid = true;
 		return;
diff --git a/core/os/input_event.cpp b/core/os/input_event.cpp
index 30fca0c155..381ba9d010 100644
--- a/core/os/input_event.cpp
+++ b/core/os/input_event.cpp
@@ -557,10 +557,31 @@ InputEventMouseButton::InputEventMouseButton() {
 
 ////////////////////////////////////////////
 
+void InputEventMouseMotion::set_tilt(const Vector2 &p_tilt) {
+
+	tilt = p_tilt;
+}
+
+Vector2 InputEventMouseMotion::get_tilt() const {
+
+	return tilt;
+}
+
+void InputEventMouseMotion::set_pressure(float p_pressure) {
+
+	pressure = p_pressure;
+}
+
+float InputEventMouseMotion::get_pressure() const {
+
+	return pressure;
+}
+
 void InputEventMouseMotion::set_relative(const Vector2 &p_relative) {
 
 	relative = p_relative;
 }
+
 Vector2 InputEventMouseMotion::get_relative() const {
 
 	return relative;
@@ -570,6 +591,7 @@ void InputEventMouseMotion::set_speed(const Vector2 &p_speed) {
 
 	speed = p_speed;
 }
+
 Vector2 InputEventMouseMotion::get_speed() const {
 
 	return speed;
@@ -590,6 +612,8 @@ Ref<InputEvent> InputEventMouseMotion::xformed_by(const Transform2D &p_xform, co
 	mm->set_modifiers_from_event(this);
 
 	mm->set_position(l);
+	mm->set_pressure(get_pressure());
+	mm->set_tilt(get_tilt());
 	mm->set_global_position(g);
 
 	mm->set_button_mask(get_button_mask());
@@ -665,17 +689,27 @@ bool InputEventMouseMotion::accumulate(const Ref<InputEvent> &p_event) {
 
 void InputEventMouseMotion::_bind_methods() {
 
+	ClassDB::bind_method(D_METHOD("set_tilt", "tilt"), &InputEventMouseMotion::set_tilt);
+	ClassDB::bind_method(D_METHOD("get_tilt"), &InputEventMouseMotion::get_tilt);
+
+	ClassDB::bind_method(D_METHOD("set_pressure", "pressure"), &InputEventMouseMotion::set_pressure);
+	ClassDB::bind_method(D_METHOD("get_pressure"), &InputEventMouseMotion::get_pressure);
+
 	ClassDB::bind_method(D_METHOD("set_relative", "relative"), &InputEventMouseMotion::set_relative);
 	ClassDB::bind_method(D_METHOD("get_relative"), &InputEventMouseMotion::get_relative);
 
 	ClassDB::bind_method(D_METHOD("set_speed", "speed"), &InputEventMouseMotion::set_speed);
 	ClassDB::bind_method(D_METHOD("get_speed"), &InputEventMouseMotion::get_speed);
 
+	ADD_PROPERTY(PropertyInfo(Variant::VECTOR2, "tilt"), "set_tilt", "get_tilt");
+	ADD_PROPERTY(PropertyInfo(Variant::REAL, "pressure"), "set_pressure", "get_pressure");
 	ADD_PROPERTY(PropertyInfo(Variant::VECTOR2, "relative"), "set_relative", "get_relative");
 	ADD_PROPERTY(PropertyInfo(Variant::VECTOR2, "speed"), "set_speed", "get_speed");
 }
 
 InputEventMouseMotion::InputEventMouseMotion() {
+
+	pressure = 0;
 }
 
 ////////////////////////////////////////
diff --git a/core/os/input_event.h b/core/os/input_event.h
index 28658e3865..14649502ee 100644
--- a/core/os/input_event.h
+++ b/core/os/input_event.h
@@ -351,6 +351,9 @@ public:
 class InputEventMouseMotion : public InputEventMouse {
 
 	GDCLASS(InputEventMouseMotion, InputEventMouse);
+
+	Vector2 tilt;
+	float pressure;
 	Vector2 relative;
 	Vector2 speed;
 
@@ -358,6 +361,12 @@ protected:
 	static void _bind_methods();
 
 public:
+	void set_tilt(const Vector2 &p_tilt);
+	Vector2 get_tilt() const;
+
+	void set_pressure(float p_pressure);
+	float get_pressure() const;
+
 	void set_relative(const Vector2 &p_relative);
 	Vector2 get_relative() const;
 
diff --git a/core/os/main_loop.cpp b/core/os/main_loop.cpp
index 5587e827ba..146a301995 100644
--- a/core/os/main_loop.cpp
+++ b/core/os/main_loop.cpp
@@ -65,6 +65,8 @@ void MainLoop::_bind_methods() {
 	BIND_CONSTANT(NOTIFICATION_OS_IME_UPDATE);
 	BIND_CONSTANT(NOTIFICATION_APP_RESUMED);
 	BIND_CONSTANT(NOTIFICATION_APP_PAUSED);
+
+	ADD_SIGNAL(MethodInfo("on_request_permissions_result", PropertyInfo(Variant::STRING, "permission"), PropertyInfo(Variant::BOOL, "granted")));
 };
 
 void MainLoop::set_init_script(const Ref<Script> &p_init_script) {
diff --git a/core/os/os.h b/core/os/os.h
index 9b46b43081..b5224c4f63 100644
--- a/core/os/os.h
+++ b/core/os/os.h
@@ -530,6 +530,8 @@ public:
 	List<String> get_restart_on_exit_arguments() const;
 
 	virtual bool request_permission(const String &p_name) { return true; }
+	virtual bool request_permissions() { return true; }
+	virtual Vector<String> get_granted_permissions() const { return Vector<String>(); }
 
 	virtual void process_and_drop_events() {}
 	OS();
diff --git a/core/packed_data_container.cpp b/core/packed_data_container.cpp
index 003e7e7428..7afaf7f0f1 100644
--- a/core/packed_data_container.cpp
+++ b/core/packed_data_container.cpp
@@ -137,6 +137,7 @@ uint32_t PackedDataContainer::_type_at_ofs(uint32_t p_ofs) const {
 int PackedDataContainer::_size(uint32_t p_ofs) const {
 
 	PoolVector<uint8_t>::Read rd = data.read();
+	ERR_FAIL_COND_V(!rd.ptr(), 0);
 	const uint8_t *r = &rd[p_ofs];
 	uint32_t type = decode_uint32(r);
 
diff --git a/core/pool_vector.h b/core/pool_vector.h
index fbd4d630be..a698e72e18 100644
--- a/core/pool_vector.h
+++ b/core/pool_vector.h
@@ -385,6 +385,7 @@ public:
 	}
 
 	inline int size() const;
+	inline bool empty() const;
 	T get(int p_index) const;
 	void set(int p_index, const T &p_val);
 	void push_back(const T &p_val);
@@ -475,6 +476,12 @@ int PoolVector<T>::size() const {
 }
 
 template <class T>
+bool PoolVector<T>::empty() const {
+
+	return alloc ? alloc->size == 0 : true;
+}
+
+template <class T>
 T PoolVector<T>::get(int p_index) const {
 
 	return operator[](p_index);
diff --git a/core/ref_ptr.cpp b/core/ref_ptr.cpp
index 961f143e5c..6da73ca41a 100644
--- a/core/ref_ptr.cpp
+++ b/core/ref_ptr.cpp
@@ -49,6 +49,14 @@ bool RefPtr::operator==(const RefPtr &p_other) const {
 	return *ref == *ref_other;
 }
 
+bool RefPtr::operator!=(const RefPtr &p_other) const {
+
+	Ref<Reference> *ref = reinterpret_cast<Ref<Reference> *>(&data[0]);
+	Ref<Reference> *ref_other = reinterpret_cast<Ref<Reference> *>(const_cast<char *>(&p_other.data[0]));
+
+	return *ref != *ref_other;
+}
+
 RefPtr::RefPtr(const RefPtr &p_other) {
 
 	memnew_placement(&data[0], Ref<Reference>);
diff --git a/core/ref_ptr.h b/core/ref_ptr.h
index f745ababa1..320cf35609 100644
--- a/core/ref_ptr.h
+++ b/core/ref_ptr.h
@@ -50,6 +50,7 @@ public:
 	bool is_null() const;
 	void operator=(const RefPtr &p_other);
 	bool operator==(const RefPtr &p_other) const;
+	bool operator!=(const RefPtr &p_other) const;
 	RID get_rid() const;
 	void unref();
 	_FORCE_INLINE_ void *get_data() const { return data; }
diff --git a/core/resource.cpp b/core/resource.cpp
index 87c92ca5b1..e0a40b6f3c 100644
--- a/core/resource.cpp
+++ b/core/resource.cpp
@@ -365,17 +365,38 @@ bool Resource::is_translation_remapped() const {
 //helps keep IDs same number when loading/saving scenes. -1 clears ID and it Returns -1 when no id stored
 void Resource::set_id_for_path(const String &p_path, int p_id) {
 	if (p_id == -1) {
-		id_for_path.erase(p_path);
+		if (ResourceCache::path_cache_lock) {
+			ResourceCache::path_cache_lock->write_lock();
+		}
+		ResourceCache::resource_path_cache[p_path].erase(get_path());
+		if (ResourceCache::path_cache_lock) {
+			ResourceCache::path_cache_lock->write_unlock();
+		}
 	} else {
-		id_for_path[p_path] = p_id;
+		if (ResourceCache::path_cache_lock) {
+			ResourceCache::path_cache_lock->write_lock();
+		}
+		ResourceCache::resource_path_cache[p_path][get_path()] = p_id;
+		if (ResourceCache::path_cache_lock) {
+			ResourceCache::path_cache_lock->write_unlock();
+		}
 	}
 }
 
 int Resource::get_id_for_path(const String &p_path) const {
-
-	if (id_for_path.has(p_path)) {
-		return id_for_path[p_path];
+	if (ResourceCache::path_cache_lock) {
+		ResourceCache::path_cache_lock->read_lock();
+	}
+	if (ResourceCache::resource_path_cache[p_path].has(get_path())) {
+		int result = ResourceCache::resource_path_cache[p_path][get_path()];
+		if (ResourceCache::path_cache_lock) {
+			ResourceCache::path_cache_lock->read_unlock();
+		}
+		return result;
 	} else {
+		if (ResourceCache::path_cache_lock) {
+			ResourceCache::path_cache_lock->read_unlock();
+		}
 		return -1;
 	}
 }
@@ -430,12 +451,21 @@ Resource::~Resource() {
 }
 
 HashMap<String, Resource *> ResourceCache::resources;
+#ifdef TOOLS_ENABLED
+HashMap<String, HashMap<String, int> > ResourceCache::resource_path_cache;
+#endif
 
 RWLock *ResourceCache::lock = NULL;
+#ifdef TOOLS_ENABLED
+RWLock *ResourceCache::path_cache_lock = NULL;
+#endif
 
 void ResourceCache::setup() {
 
 	lock = RWLock::create();
+#ifdef TOOLS_ENABLED
+	path_cache_lock = RWLock::create();
+#endif
 }
 
 void ResourceCache::clear() {
diff --git a/core/resource.h b/core/resource.h
index 038b4f6278..3e1fe07137 100644
--- a/core/resource.h
+++ b/core/resource.h
@@ -84,9 +84,7 @@ protected:
 
 	void _set_path(const String &p_path);
 	void _take_over_path(const String &p_path);
-#ifdef TOOLS_ENABLED
-	Map<String, int> id_for_path;
-#endif
+
 public:
 	static Node *(*_get_local_scene_func)(); //used by editor
 
@@ -152,6 +150,10 @@ class ResourceCache {
 	friend class ResourceLoader; //need the lock
 	static RWLock *lock;
 	static HashMap<String, Resource *> resources;
+#ifdef TOOLS_ENABLED
+	static HashMap<String, HashMap<String, int> > resource_path_cache; // each tscn has a set of resource paths and IDs
+	static RWLock *path_cache_lock;
+#endif // TOOLS_ENABLED
 	friend void unregister_core_types();
 	static void clear();
 	friend void register_core_types();
diff --git a/core/script_language.cpp b/core/script_language.cpp
index 7201773ea5..cbe4681eca 100644
--- a/core/script_language.cpp
+++ b/core/script_language.cpp
@@ -218,6 +218,7 @@ void ScriptServer::global_classes_clear() {
 }
 
 void ScriptServer::add_global_class(const StringName &p_class, const StringName &p_base, const StringName &p_language, const String &p_path) {
+	ERR_FAIL_COND_MSG(p_class == p_base || (global_classes.has(p_base) && get_global_class_native_base(p_base) == p_class), "Cyclic inheritance in script class.");
 	GlobalScriptClass g;
 	g.language = p_language;
 	g.path = p_path;
diff --git a/core/translation.cpp b/core/translation.cpp
index a0902d71fc..4a1ac26433 100644
--- a/core/translation.cpp
+++ b/core/translation.cpp
@@ -986,6 +986,7 @@ Array TranslationServer::get_loaded_locales() const {
 	for (const Set<Ref<Translation> >::Element *E = translations.front(); E; E = E->next()) {
 
 		const Ref<Translation> &t = E->get();
+		ERR_FAIL_COND_V(t.is_null(), Array());
 		String l = t->get_locale();
 
 		locales.push_back(l);
@@ -1057,6 +1058,7 @@ StringName TranslationServer::translate(const StringName &p_message) const {
 	for (const Set<Ref<Translation> >::Element *E = translations.front(); E; E = E->next()) {
 
 		const Ref<Translation> &t = E->get();
+		ERR_FAIL_COND_V(t.is_null(), StringName(""));
 		String l = t->get_locale();
 		if (lptr[0] != l[0] || lptr[1] != l[1])
 			continue; // Language code does not match.
@@ -1085,6 +1087,7 @@ StringName TranslationServer::translate(const StringName &p_message) const {
 		for (const Set<Ref<Translation> >::Element *E = translations.front(); E; E = E->next()) {
 
 			const Ref<Translation> &t = E->get();
+			ERR_FAIL_COND_V(t.is_null(), StringName(""));
 			String l = t->get_locale();
 			if (fptr[0] != l[0] || fptr[1] != l[1])
 				continue; // Language code does not match.
diff --git a/core/ustring.cpp b/core/ustring.cpp
index f029ae4200..7ee2fee312 100644
--- a/core/ustring.cpp
+++ b/core/ustring.cpp
@@ -4058,6 +4058,11 @@ String itos(int64_t p_val) {
 	return String::num_int64(p_val);
 }
 
+String uitos(uint64_t p_val) {
+
+	return String::num_uint64(p_val);
+}
+
 String rtos(double p_val) {
 
 	return String::num(p_val);
diff --git a/core/ustring.h b/core/ustring.h
index 15e2c07d9f..dfc5044942 100644
--- a/core/ustring.h
+++ b/core/ustring.h
@@ -369,6 +369,7 @@ String operator+(const char *p_chr, const String &p_str);
 String operator+(CharType p_chr, const String &p_str);
 
 String itos(int64_t p_val);
+String uitos(uint64_t p_val);
 String rtos(double p_val);
 String rtoss(double p_val); //scientific version
 
diff --git a/core/variant.cpp b/core/variant.cpp
index 16bbf94c54..e0cc6685f4 100644
--- a/core/variant.cpp
+++ b/core/variant.cpp
@@ -3299,7 +3299,7 @@ String vformat(const String &p_text, const Variant &p1, const Variant &p2, const
 	bool error = false;
 	String fmt = p_text.sprintf(args, &error);
 
-	ERR_FAIL_COND_V(error, String());
+	ERR_FAIL_COND_V_MSG(error, String(), fmt);
 
 	return fmt;
 }
diff --git a/core/variant_call.cpp b/core/variant_call.cpp
index 40b944744b..f7a3438d32 100644
--- a/core/variant_call.cpp
+++ b/core/variant_call.cpp
@@ -626,6 +626,7 @@ struct _VariantCall {
 	}
 
 	VCALL_LOCALMEM0R(PoolByteArray, size);
+	VCALL_LOCALMEM0R(PoolByteArray, empty);
 	VCALL_LOCALMEM2(PoolByteArray, set);
 	VCALL_LOCALMEM1R(PoolByteArray, get);
 	VCALL_LOCALMEM1(PoolByteArray, push_back);
@@ -638,6 +639,7 @@ struct _VariantCall {
 	VCALL_LOCALMEM2R(PoolByteArray, subarray);
 
 	VCALL_LOCALMEM0R(PoolIntArray, size);
+	VCALL_LOCALMEM0R(PoolIntArray, empty);
 	VCALL_LOCALMEM2(PoolIntArray, set);
 	VCALL_LOCALMEM1R(PoolIntArray, get);
 	VCALL_LOCALMEM1(PoolIntArray, push_back);
@@ -649,6 +651,7 @@ struct _VariantCall {
 	VCALL_LOCALMEM0(PoolIntArray, invert);
 
 	VCALL_LOCALMEM0R(PoolRealArray, size);
+	VCALL_LOCALMEM0R(PoolRealArray, empty);
 	VCALL_LOCALMEM2(PoolRealArray, set);
 	VCALL_LOCALMEM1R(PoolRealArray, get);
 	VCALL_LOCALMEM1(PoolRealArray, push_back);
@@ -660,6 +663,7 @@ struct _VariantCall {
 	VCALL_LOCALMEM0(PoolRealArray, invert);
 
 	VCALL_LOCALMEM0R(PoolStringArray, size);
+	VCALL_LOCALMEM0R(PoolStringArray, empty);
 	VCALL_LOCALMEM2(PoolStringArray, set);
 	VCALL_LOCALMEM1R(PoolStringArray, get);
 	VCALL_LOCALMEM1(PoolStringArray, push_back);
@@ -672,6 +676,7 @@ struct _VariantCall {
 	VCALL_LOCALMEM1R(PoolStringArray, join);
 
 	VCALL_LOCALMEM0R(PoolVector2Array, size);
+	VCALL_LOCALMEM0R(PoolVector2Array, empty);
 	VCALL_LOCALMEM2(PoolVector2Array, set);
 	VCALL_LOCALMEM1R(PoolVector2Array, get);
 	VCALL_LOCALMEM1(PoolVector2Array, push_back);
@@ -683,6 +688,7 @@ struct _VariantCall {
 	VCALL_LOCALMEM0(PoolVector2Array, invert);
 
 	VCALL_LOCALMEM0R(PoolVector3Array, size);
+	VCALL_LOCALMEM0R(PoolVector3Array, empty);
 	VCALL_LOCALMEM2(PoolVector3Array, set);
 	VCALL_LOCALMEM1R(PoolVector3Array, get);
 	VCALL_LOCALMEM1(PoolVector3Array, push_back);
@@ -694,6 +700,7 @@ struct _VariantCall {
 	VCALL_LOCALMEM0(PoolVector3Array, invert);
 
 	VCALL_LOCALMEM0R(PoolColorArray, size);
+	VCALL_LOCALMEM0R(PoolColorArray, empty);
 	VCALL_LOCALMEM2(PoolColorArray, set);
 	VCALL_LOCALMEM1R(PoolColorArray, get);
 	VCALL_LOCALMEM1(PoolColorArray, push_back);
@@ -1782,6 +1789,7 @@ void register_variant_methods() {
 	ADDFUNC0R(ARRAY, NIL, Array, min, varray());
 
 	ADDFUNC0R(POOL_BYTE_ARRAY, INT, PoolByteArray, size, varray());
+	ADDFUNC0R(POOL_BYTE_ARRAY, BOOL, PoolByteArray, empty, varray());
 	ADDFUNC2(POOL_BYTE_ARRAY, NIL, PoolByteArray, set, INT, "idx", INT, "byte", varray());
 	ADDFUNC1(POOL_BYTE_ARRAY, NIL, PoolByteArray, push_back, INT, "byte", varray());
 	ADDFUNC1(POOL_BYTE_ARRAY, NIL, PoolByteArray, append, INT, "byte", varray());
@@ -1799,6 +1807,7 @@ void register_variant_methods() {
 	ADDFUNC2R(POOL_BYTE_ARRAY, POOL_BYTE_ARRAY, PoolByteArray, decompress, INT, "buffer_size", INT, "compression_mode", varray(0));
 
 	ADDFUNC0R(POOL_INT_ARRAY, INT, PoolIntArray, size, varray());
+	ADDFUNC0R(POOL_INT_ARRAY, BOOL, PoolIntArray, empty, varray());
 	ADDFUNC2(POOL_INT_ARRAY, NIL, PoolIntArray, set, INT, "idx", INT, "integer", varray());
 	ADDFUNC1(POOL_INT_ARRAY, NIL, PoolIntArray, push_back, INT, "integer", varray());
 	ADDFUNC1(POOL_INT_ARRAY, NIL, PoolIntArray, append, INT, "integer", varray());
@@ -1809,6 +1818,7 @@ void register_variant_methods() {
 	ADDFUNC0(POOL_INT_ARRAY, NIL, PoolIntArray, invert, varray());
 
 	ADDFUNC0R(POOL_REAL_ARRAY, INT, PoolRealArray, size, varray());
+	ADDFUNC0R(POOL_REAL_ARRAY, BOOL, PoolRealArray, empty, varray());
 	ADDFUNC2(POOL_REAL_ARRAY, NIL, PoolRealArray, set, INT, "idx", REAL, "value", varray());
 	ADDFUNC1(POOL_REAL_ARRAY, NIL, PoolRealArray, push_back, REAL, "value", varray());
 	ADDFUNC1(POOL_REAL_ARRAY, NIL, PoolRealArray, append, REAL, "value", varray());
@@ -1819,6 +1829,7 @@ void register_variant_methods() {
 	ADDFUNC0(POOL_REAL_ARRAY, NIL, PoolRealArray, invert, varray());
 
 	ADDFUNC0R(POOL_STRING_ARRAY, INT, PoolStringArray, size, varray());
+	ADDFUNC0R(POOL_STRING_ARRAY, BOOL, PoolStringArray, empty, varray());
 	ADDFUNC2(POOL_STRING_ARRAY, NIL, PoolStringArray, set, INT, "idx", STRING, "string", varray());
 	ADDFUNC1(POOL_STRING_ARRAY, NIL, PoolStringArray, push_back, STRING, "string", varray());
 	ADDFUNC1(POOL_STRING_ARRAY, NIL, PoolStringArray, append, STRING, "string", varray());
@@ -1830,6 +1841,7 @@ void register_variant_methods() {
 	ADDFUNC1(POOL_STRING_ARRAY, STRING, PoolStringArray, join, STRING, "delimiter", varray());
 
 	ADDFUNC0R(POOL_VECTOR2_ARRAY, INT, PoolVector2Array, size, varray());
+	ADDFUNC0R(POOL_VECTOR2_ARRAY, BOOL, PoolVector2Array, empty, varray());
 	ADDFUNC2(POOL_VECTOR2_ARRAY, NIL, PoolVector2Array, set, INT, "idx", VECTOR2, "vector2", varray());
 	ADDFUNC1(POOL_VECTOR2_ARRAY, NIL, PoolVector2Array, push_back, VECTOR2, "vector2", varray());
 	ADDFUNC1(POOL_VECTOR2_ARRAY, NIL, PoolVector2Array, append, VECTOR2, "vector2", varray());
@@ -1840,6 +1852,7 @@ void register_variant_methods() {
 	ADDFUNC0(POOL_VECTOR2_ARRAY, NIL, PoolVector2Array, invert, varray());
 
 	ADDFUNC0R(POOL_VECTOR3_ARRAY, INT, PoolVector3Array, size, varray());
+	ADDFUNC0R(POOL_VECTOR3_ARRAY, BOOL, PoolVector3Array, empty, varray());
 	ADDFUNC2(POOL_VECTOR3_ARRAY, NIL, PoolVector3Array, set, INT, "idx", VECTOR3, "vector3", varray());
 	ADDFUNC1(POOL_VECTOR3_ARRAY, NIL, PoolVector3Array, push_back, VECTOR3, "vector3", varray());
 	ADDFUNC1(POOL_VECTOR3_ARRAY, NIL, PoolVector3Array, append, VECTOR3, "vector3", varray());
@@ -1850,6 +1863,7 @@ void register_variant_methods() {
 	ADDFUNC0(POOL_VECTOR3_ARRAY, NIL, PoolVector3Array, invert, varray());
 
 	ADDFUNC0R(POOL_COLOR_ARRAY, INT, PoolColorArray, size, varray());
+	ADDFUNC0R(POOL_COLOR_ARRAY, BOOL, PoolColorArray, empty, varray());
 	ADDFUNC2(POOL_COLOR_ARRAY, NIL, PoolColorArray, set, INT, "idx", COLOR, "color", varray());
 	ADDFUNC1(POOL_COLOR_ARRAY, NIL, PoolColorArray, push_back, COLOR, "color", varray());
 	ADDFUNC1(POOL_COLOR_ARRAY, NIL, PoolColorArray, append, COLOR, "color", varray());
diff --git a/core/vmap.h b/core/vmap.h
index fde9723d71..ed66b46993 100644
--- a/core/vmap.h
+++ b/core/vmap.h
@@ -196,8 +196,7 @@ public:
 
 		int pos = _find_exact(p_key);
 		if (pos < 0) {
-			V val;
-			pos = insert(p_key, val);
+			pos = insert(p_key, V());
 		}
 
 		return _cowdata.get_m(pos).value;