Add experimental-godot-api feature and hide experimental classes behind it

Author: Bromeon

godot-codegen/Cargo.toml

@@ -13,6 +13,7 @@ codegen-fmt = []
 codegen-full = []
 double-precision = []
 custom-godot = ["godot-bindings/custom-godot"]
+experimental-godot-api = []
 
 [dependencies]
 godot-bindings = { path = "../godot-bindings" }

godot-codegen/src/special_cases.rs

@@ -44,14 +44,12 @@ pub(crate) fn is_deleted(class_name: &TyName, method: &ClassMethod, ctx: &mut Co
 
 #[rustfmt::skip]
 pub(crate) fn is_class_deleted(class_name: &TyName) -> bool {
-    let class_name = class_name.godot_ty.as_str();
-
-    // TODO feature-gate experimental classes.
-    /*
+    // Exclude experimental APIs unless opted-in.
     if !cfg!(feature = "experimental-godot-api") && is_class_experimental(class_name) {
         return true;
     }
-    */
+
+    let class_name = class_name.godot_ty.as_str();
 
     // OpenXR has not been available for macOS before 4.2.
     // See e.g. https://github.com/GodotVR/godot-xr-tools/issues/479.
@@ -105,7 +103,6 @@ pub(crate) fn is_class_deleted(class_name: &TyName) -> bool {
 }
 
 #[rustfmt::skip]
-#[allow(dead_code)] // remove once used.
 fn is_class_experimental(class_name: &TyName) -> bool {
     // These classes are currently hardcoded, but the information is available in Godot's doc/classes directory.
     // The XML file contains a property <class name="NavigationMesh" ... is_experimental="true">.

godot-core/Cargo.toml

@@ -14,6 +14,7 @@ codegen-fmt = ["godot-ffi/codegen-fmt", "godot-codegen/codegen-fmt"]
 codegen-full = ["godot-codegen/codegen-full"]
 double-precision = ["godot-codegen/double-precision"]
 custom-godot = ["godot-ffi/custom-godot", "godot-codegen/custom-godot"]
+experimental-godot-api = ["godot-codegen/experimental-godot-api"]
 threads = []
 
 [dependencies]

godot-ffi/Cargo.toml

@@ -10,6 +10,7 @@ categories = ["game-engines", "graphics"]
 [features]
 custom-godot = ["godot-bindings/custom-godot"]
 codegen-fmt = ["godot-codegen/codegen-fmt"]
+experimental-godot-api = ["godot-codegen/experimental-godot-api"]
 trace = []
 
 [dependencies]

godot/Cargo.toml

@@ -14,6 +14,7 @@ double-precision = ["godot-core/double-precision"]
 formatted = ["godot-core/codegen-fmt"]
 serde = ["godot-core/serde"]
 threads = ["godot-core/threads"]
+experimental-godot-api = ["godot-core/experimental-godot-api"]
 
 # Private features, they are under no stability guarantee
 codegen-full = ["godot-core/codegen-full"]

godot/src/lib.rs

@@ -141,6 +141,11 @@
 //!   multi-threaded references. The safety aspects of this are not ironed out yet; use at your own risk. The API may also change
 //!   at any time.
 //!
+//! * **`experimental-godot-api`**
+//!
+//!   Access to `godot::engine` APIs that Godot marks "experimental". These are under heavy development and may change at any time.
+//!   If you opt in to this feature, expect breaking changes at compile and runtime.
+//!
 //! # Public API
 //!
 //! Some symbols in the API are not intended for users, however Rust's visibility feature is not strong enough to express that in all cases