Add ability to create tooltip descriptions for dynamically exported properties

Author: ryevdokimov

core/object/object.cpp

@@ -2055,6 +2055,8 @@ void Object::_bind_methods() {
 		BIND_OBJ_CORE_METHOD(mi);
 	}
 
+	BIND_OBJ_CORE_METHOD(MethodInfo(Variant::STRING, "_get_property_description", PropertyInfo(Variant::STRING_NAME, "property")));
+
 	// These are actually `Variant` methods, but that doesn't matter since scripts can't inherit built-in types.
 
 	BIND_OBJ_CORE_METHOD(MethodInfo(Variant::BOOL, "_iter_init", PropertyInfo(Variant::ARRAY, "iter")));

doc/classes/Object.xml

@@ -270,6 +270,30 @@
 				[b]Note:[/b] Unlike other virtual methods, this method is called automatically for every script that overrides it. This means that the base implementation should not be called via [code]super[/code] in GDScript or its equivalents in other languages. Call order depends on the [code]reversed[/code] argument of [method notification] and varies between different notifications. Most notifications are sent in the forward order (i.e. Object class first, most derived class last).
 			</description>
 		</method>
+		<method name="_get_property_description" qualifiers="virtual">
+			<return type="String" />
+			<param index="0" name="property" type="StringName" />
+			<description>
+				Override this method to provide a custom description for the given [param property]. The description is displayed as a tooltip in the Inspector dock when hovering over the property.
+				This is particularly useful for dynamically exported properties (via [method _get_property_list]) which cannot be documented using the standard documentation system.
+				[codeblocks]
+				[gdscript]
+				func _get_property_description(property):
+					if property == "my_dynamic_property":
+						return "A dynamically exported property with a custom tooltip."
+					return ""
+				[/gdscript]
+				[csharp]
+				public override string _GetPropertyDescription(StringName property)
+				{
+					if (property == "my_dynamic_property")
+						return "A dynamically exported property with a custom tooltip.";
+					return "";
+				}
+				[/csharp]
+				[/codeblocks]
+			</description>
+		</method>
 		<method name="_property_can_revert" qualifiers="virtual">
 			<return type="bool" />
 			<param index="0" name="property" type="StringName" />

editor/inspector/editor_inspector.cpp

@@ -1405,6 +1405,16 @@ Control *EditorProperty::make_custom_tooltip(const String &p_text) const {
 		}
 	}
 
+	if (object->has_method("_get_property_description")) {
+		const String custom_description = object->call("_get_property_description", property);
+		if (!custom_description.is_empty()) {
+			if (!prologue.is_empty()) {
+				prologue += '\n';
+			}
+			prologue += custom_description;
+		}
+	}
+
 	if (!symbol.is_empty() || !prologue.is_empty()) {
 		return EditorHelpBitTooltip::make_tooltip(const_cast<EditorProperty *>(this), symbol, prologue);
 	}
@@ -2304,6 +2314,16 @@ Control *EditorInspectorSection::make_custom_tooltip(const String &p_text) const
 		}
 	}
 
+	if (object->has_method("_get_property_description")) {
+		const String custom_description = object->call("_get_property_description", related_enable_property);
+		if (!custom_description.is_empty()) {
+			if (!prologue.is_empty()) {
+				prologue += '\n';
+			}
+			prologue += custom_description;
+		}
+	}
+
 	if (!symbol.is_empty() || !prologue.is_empty()) {
 		return EditorHelpBitTooltip::make_tooltip(const_cast<EditorInspectorSection *>(this), symbol, prologue);
 	}