Fix typo and ensure backwards compatibility for changed property names

Changes to the name of the `navmesh` and `navpoly` properties on
`NavigationRegion` caused navigation data to be lost on load.
This PR creates uses `_set`/`_get` to handle compatibility with the
older names on load, preserving the data.

Also fixes a typo on `get_vertices_per_polygon` in `NavigationMesh`,
and renames the property to remove the `polygon_` prefix which doesn't
match the setter/getter.

Co-authored-by: Rémi Verschelde <rverschelde@gmail.com>

7 files changed, 83 insertions, 16 deletions

diff --git a/scene/2d/navigation_region_2d.cpp b/scene/2d/navigation_region_2d.cpp
index e030628110..675ef7c780 100644
--- a/scene/2d/navigation_region_2d.cpp
+++ b/scene/2d/navigation_region_2d.cpp
@@ -309,6 +309,25 @@ void NavigationRegion2D::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "travel_cost"), "set_travel_cost", "get_travel_cost");
 }
 
+#ifndef DISABLE_DEPRECATED
+// Compatibility with earlier 4.0 betas.
+bool NavigationRegion2D::_set(const StringName &p_name, const Variant &p_value) {
+	if (p_name == "navpoly") {
+		set_navigation_polygon(p_value);
+		return true;
+	}
+	return false;
+}
+
+bool NavigationRegion2D::_get(const StringName &p_name, Variant &r_ret) const {
+	if (p_name == "navpoly") {
+		r_ret = get_navigation_polygon();
+		return true;
+	}
+	return false;
+}
+#endif // DISABLE_DEPRECATED
+
 NavigationRegion2D::NavigationRegion2D() {
 	set_notify_transform(true);
 
diff --git a/scene/2d/navigation_region_2d.h b/scene/2d/navigation_region_2d.h
index 216e6088bc..45029fd95f 100644
--- a/scene/2d/navigation_region_2d.h
+++ b/scene/2d/navigation_region_2d.h
@@ -50,6 +50,11 @@ protected:
 	void _notification(int p_what);
 	static void _bind_methods();
 
+#ifndef DISABLE_DEPRECATED
+	bool _set(const StringName &p_name, const Variant &p_value);
+	bool _get(const StringName &p_name, Variant &r_ret) const;
+#endif // DISABLE_DEPRECATED
+
 public:
 #ifdef TOOLS_ENABLED
 	virtual Rect2 _edit_get_rect() const override;
diff --git a/scene/3d/navigation_region_3d.cpp b/scene/3d/navigation_region_3d.cpp
index 520bf0a1aa..86b78f847e 100644
--- a/scene/3d/navigation_region_3d.cpp
+++ b/scene/3d/navigation_region_3d.cpp
@@ -320,6 +320,25 @@ void NavigationRegion3D::_bind_methods() {
 	ADD_SIGNAL(MethodInfo("bake_finished"));
 }
 
+#ifndef DISABLE_DEPRECATED
+// Compatibility with earlier 4.0 betas.
+bool NavigationRegion3D::_set(const StringName &p_name, const Variant &p_value) {
+	if (p_name == "navmesh") {
+		set_navigation_mesh(p_value);
+		return true;
+	}
+	return false;
+}
+
+bool NavigationRegion3D::_get(const StringName &p_name, Variant &r_ret) const {
+	if (p_name == "navmesh") {
+		r_ret = get_navigation_mesh();
+		return true;
+	}
+	return false;
+}
+#endif // DISABLE_DEPRECATED
+
 void NavigationRegion3D::_navigation_changed() {
 	update_gizmos();
 	update_configuration_warnings();
diff --git a/scene/3d/navigation_region_3d.h b/scene/3d/navigation_region_3d.h
index 7dcfa9cfa4..811c0885a1 100644
--- a/scene/3d/navigation_region_3d.h
+++ b/scene/3d/navigation_region_3d.h
@@ -64,6 +64,11 @@ protected:
 	void _notification(int p_what);
 	static void _bind_methods();
 
+#ifndef DISABLE_DEPRECATED
+	bool _set(const StringName &p_name, const Variant &p_value);
+	bool _get(const StringName &p_name, Variant &r_ret) const;
+#endif // DISABLE_DEPRECATED
+
 public:
 	void set_enabled(bool p_enabled);
 	bool is_enabled() const;
diff --git a/scene/resources/mesh_library.cpp b/scene/resources/mesh_library.cpp
index 8b47d12308..4ac864e11a 100644
--- a/scene/resources/mesh_library.cpp
+++ b/scene/resources/mesh_library.cpp
@@ -61,6 +61,12 @@ bool MeshLibrary::_set(const StringName &p_name, const Variant &p_value) {
 			set_item_navigation_mesh(idx, p_value);
 		} else if (what == "navigation_mesh_transform") {
 			set_item_navigation_mesh_transform(idx, p_value);
+#ifndef DISABLE_DEPRECATED
+		} else if (what == "navmesh") { // Renamed in 4.0 beta 9.
+			set_item_navigation_mesh(idx, p_value);
+		} else if (what == "navmesh_transform") { // Renamed in 4.0 beta 9.
+			set_item_navigation_mesh_transform(idx, p_value);
+#endif // DISABLE_DEPRECATED
 		} else {
 			return false;
 		}
@@ -89,6 +95,12 @@ bool MeshLibrary::_get(const StringName &p_name, Variant &r_ret) const {
 		r_ret = get_item_navigation_mesh(idx);
 	} else if (what == "navigation_mesh_transform") {
 		r_ret = get_item_navigation_mesh_transform(idx);
+#ifndef DISABLE_DEPRECATED
+	} else if (what == "navmesh") { // Renamed in 4.0 beta 9.
+		r_ret = get_item_navigation_mesh(idx);
+	} else if (what == "navmesh_transform") { // Renamed in 4.0 beta 9.
+		r_ret = get_item_navigation_mesh_transform(idx);
+#endif // DISABLE_DEPRECATED
 	} else if (what == "preview") {
 		r_ret = get_item_preview(idx);
 	} else {
diff --git a/scene/resources/navigation_mesh.cpp b/scene/resources/navigation_mesh.cpp
index 76552faec1..5d9adccaac 100644
--- a/scene/resources/navigation_mesh.cpp
+++ b/scene/resources/navigation_mesh.cpp
@@ -225,13 +225,13 @@ float NavigationMesh::get_edge_max_error() const {
 	return edge_max_error;
 }
 
-void NavigationMesh::set_vertices_per_polyon(float p_value) {
+void NavigationMesh::set_vertices_per_polygon(float p_value) {
 	ERR_FAIL_COND(p_value < 3);
-	vertices_per_polyon = p_value;
+	vertices_per_polygon = p_value;
 }
 
-float NavigationMesh::get_vertices_per_polyon() const {
-	return vertices_per_polyon;
+float NavigationMesh::get_vertices_per_polygon() const {
+	return vertices_per_polygon;
 }
 
 void NavigationMesh::set_detail_sample_distance(float p_value) {
@@ -483,8 +483,8 @@ void NavigationMesh::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_edge_max_error", "edge_max_error"), &NavigationMesh::set_edge_max_error);
 	ClassDB::bind_method(D_METHOD("get_edge_max_error"), &NavigationMesh::get_edge_max_error);
 
-	ClassDB::bind_method(D_METHOD("set_vertices_per_polyon", "vertices_per_polyon"), &NavigationMesh::set_vertices_per_polyon);
-	ClassDB::bind_method(D_METHOD("get_vertices_per_polyon"), &NavigationMesh::get_vertices_per_polyon);
+	ClassDB::bind_method(D_METHOD("set_vertices_per_polygon", "vertices_per_polygon"), &NavigationMesh::set_vertices_per_polygon);
+	ClassDB::bind_method(D_METHOD("get_vertices_per_polygon"), &NavigationMesh::get_vertices_per_polygon);
 
 	ClassDB::bind_method(D_METHOD("set_detail_sample_distance", "detail_sample_dist"), &NavigationMesh::set_detail_sample_distance);
 	ClassDB::bind_method(D_METHOD("get_detail_sample_distance"), &NavigationMesh::get_detail_sample_distance);
@@ -544,8 +544,8 @@ void NavigationMesh::_bind_methods() {
 	ADD_GROUP("Edges", "edge_");
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "edge_max_length", PROPERTY_HINT_RANGE, "0.0,50.0,0.01,or_greater,suffix:m"), "set_edge_max_length", "get_edge_max_length");
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "edge_max_error", PROPERTY_HINT_RANGE, "0.1,3.0,0.01,or_greater,suffix:m"), "set_edge_max_error", "get_edge_max_error");
-	ADD_GROUP("Polygons", "polygon_");
-	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "polygon_vertices_per_polyon", PROPERTY_HINT_RANGE, "3.0,12.0,1.0,or_greater"), "set_vertices_per_polyon", "get_vertices_per_polyon");
+	ADD_GROUP("Polygons", "");
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "vertices_per_polygon", PROPERTY_HINT_RANGE, "3.0,12.0,1.0,or_greater"), "set_vertices_per_polygon", "get_vertices_per_polygon");
 	ADD_GROUP("Details", "detail_");
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "detail_sample_distance", PROPERTY_HINT_RANGE, "0.1,16.0,0.01,or_greater,suffix:m"), "set_detail_sample_distance", "get_detail_sample_distance");
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "detail_sample_max_error", PROPERTY_HINT_RANGE, "0.0,16.0,0.01,or_greater,suffix:m"), "set_detail_sample_max_error", "get_detail_sample_max_error");
@@ -595,13 +595,16 @@ bool NavigationMesh::_set(const StringName &p_name, const Variant &p_value) {
 		// Compatibility with pre-3.5 "category/path" property names.
 		prop_name = prop_name.replace("/", "_");
 		if (prop_name == "sample_partition_type_sample_partition_type") {
-			set("sample_partition_type", p_value);
+			set_sample_partition_type((NavigationMesh::SamplePartitionType)p_value.operator int());
 		} else if (prop_name == "filter_filter_walkable_low_height_spans") {
-			set("filter_walkable_low_height_spans", p_value);
+			set_filter_walkable_low_height_spans(p_value);
 		} else {
 			set(prop_name, p_value);
 		}
-
+		return true;
+	}
+	if (p_name == "polygon_verts_per_poly") { // Renamed in 4.0 beta 9.
+		set_vertices_per_polygon(p_value);
 		return true;
 	}
 	return false;
@@ -613,14 +616,18 @@ bool NavigationMesh::_get(const StringName &p_name, Variant &r_ret) const {
 		// Compatibility with pre-3.5 "category/path" property names.
 		prop_name = prop_name.replace("/", "_");
 		if (prop_name == "sample_partition_type_sample_partition_type") {
-			r_ret = get("sample_partition_type");
+			r_ret = get_sample_partition_type();
 		} else if (prop_name == "filter_filter_walkable_low_height_spans") {
-			r_ret = get("filter_walkable_low_height_spans");
+			r_ret = get_filter_walkable_low_height_spans();
 		} else {
 			r_ret = get(prop_name);
 		}
 		return true;
 	}
+	if (p_name == "polygon_verts_per_poly") { // Renamed in 4.0 beta 9.
+		r_ret = get_vertices_per_polygon();
+		return true;
+	}
 	return false;
 }
 #endif // DISABLE_DEPRECATED
diff --git a/scene/resources/navigation_mesh.h b/scene/resources/navigation_mesh.h
index 93880603eb..3d072423db 100644
--- a/scene/resources/navigation_mesh.h
+++ b/scene/resources/navigation_mesh.h
@@ -101,7 +101,7 @@ protected:
 	float region_merge_size = 20.0f;
 	float edge_max_length = 12.0f;
 	float edge_max_error = 1.3f;
-	float vertices_per_polyon = 6.0f;
+	float vertices_per_polygon = 6.0f;
 	float detail_sample_distance = 6.0f;
 	float detail_sample_max_error = 1.0f;
 
@@ -168,8 +168,8 @@ public:
 	void set_edge_max_error(float p_value);
 	float get_edge_max_error() const;
 
-	void set_vertices_per_polyon(float p_value);
-	float get_vertices_per_polyon() const;
+	void set_vertices_per_polygon(float p_value);
+	float get_vertices_per_polygon() const;
 
 	void set_detail_sample_distance(float p_value);
 	float get_detail_sample_distance() const;