feat(core): add Specta integration (#9392)

Author: oscartbeaumont

Diff for: .changes/core-specta-integration.md

@@ -0,0 +1,5 @@
+---
+"tauri": patch:feat
+---
+
+Add `specta` feature flag which adds `specta` support for `AppHandle`, `State`, `Window`, `Webview` and `WebviewWindow` types. 

Diff for: Cargo.lock

@@ -23,7 +23,8 @@ features = [
   "devtools",
   "image-png",
   "protocol-asset",
-  "test"
+  "test",
+  "specta"
 ]
 rustc-args = [ "--cfg", "docsrs" ]
 rustdoc-args = [ "--cfg", "docsrs" ]
@@ -74,6 +75,7 @@ tracing = { version = "0.1", optional = true }
 heck = "0.4"
 log = "0.4"
 dunce = "1"
+specta = { version = "^2.0.0-rc.9", optional = true,  default-features = false, features = ["function"] }
 
 [target."cfg(any(target_os = \"linux\", target_os = \"dragonfly\", target_os = \"freebsd\", target_os = \"openbsd\", target_os = \"netbsd\", target_os = \"windows\", target_os = \"macos\"))".dependencies]
 muda = { version = "0.13", default-features = false, features = [ "serde" ] }
@@ -156,6 +158,7 @@ config-toml = [ "tauri-macros/config-toml" ]
 image-ico = [ "image/ico" ]
 image-png = [ "image/png" ]
 macos-proxy = [ "tauri-runtime-wry/macos-proxy" ]
+specta = ["dep:specta"]
 
 [[example]]
 name = "commands"

Diff for: core/tauri/Cargo.toml

@@ -37,6 +37,7 @@
 //! - **image-ico**: Adds support to parse `.ico` image, see [`Image`].
 //! - **image-png**: Adds support to parse `.png` image, see [`Image`].
 //! - **macos-proxy**: Adds support for [`WebviewBuilder::proxy_url`] on macOS. Requires macOS 14+.
+//! - **specta**: Add support for [`specta::specta`](https://docs.rs/specta/%5E2.0.0-rc.9/specta/attr.specta.html) with Tauri arguments such as [`State`](crate::State), [`Window`](crate::Window) and [`AppHandle`](crate::AppHandle)
 //!
 //! ## Cargo allowlist features
 //!
@@ -986,6 +987,41 @@ pub(crate) use run_main_thread;
 #[cfg_attr(docsrs, doc(cfg(feature = "test")))]
 pub mod test;
 
+#[cfg(feature = "specta")]
+const _: () = {
+  use specta::{function::FunctionArg, DataType, TypeMap};
+
+  impl<'r, T: Send + Sync + 'static> FunctionArg for crate::State<'r, T> {
+    fn to_datatype(_: &mut TypeMap) -> Option<DataType> {
+      None
+    }
+  }
+
+  impl<R: crate::Runtime> FunctionArg for crate::AppHandle<R> {
+    fn to_datatype(_: &mut TypeMap) -> Option<DataType> {
+      None
+    }
+  }
+
+  impl<R: crate::Runtime> FunctionArg for crate::Window<R> {
+    fn to_datatype(_: &mut TypeMap) -> Option<DataType> {
+      None
+    }
+  }
+
+  impl<R: crate::Runtime> FunctionArg for crate::Webview<R> {
+    fn to_datatype(_: &mut TypeMap) -> Option<DataType> {
+      None
+    }
+  }
+
+  impl<R: crate::Runtime> FunctionArg for crate::WebviewWindow<R> {
+    fn to_datatype(_: &mut TypeMap) -> Option<DataType> {
+      None
+    }
+  }
+};
+
 #[cfg(test)]
 mod tests {
   use cargo_toml::Manifest;