fix basic wasm nothreads compilation

Author: PgBiel

godot-core/src/private.rs

@@ -262,7 +262,7 @@ where
             godot_error!("{message}");
         }
         eprintln!("{message}");
-        #[cfg(debug_assertions)]
+        #[cfg(debug_assertions)] // TODO: remove too?
         eprintln!("{}", std::backtrace::Backtrace::capture());
         let _ignored_result = std::io::stderr().flush();
     }));
@@ -281,12 +281,12 @@ pub(crate) fn has_error_print_level(level: u8) -> bool {
 /// Internal type used to store context information for debug purposes. Debug context is stored on the thread-local
 /// ERROR_CONTEXT_STACK, which can later be used to retrieve the current context in the event of a panic. This value
 /// probably shouldn't be used directly; use ['get_gdext_panic_context()'](get_gdext_panic_context) instead.
-#[cfg(debug_assertions)]
+#[cfg(all(debug_assertions, not(wasm_nothreads)))]
 struct ScopedFunctionStack {
     functions: Vec<*const dyn Fn() -> String>,
 }
 
-#[cfg(debug_assertions)]
+#[cfg(all(debug_assertions, not(wasm_nothreads)))]
 impl ScopedFunctionStack {
     /// # Safety
     /// Function must be removed (using [`pop_function()`](Self::pop_function)) before lifetime is invalidated.
@@ -311,7 +311,7 @@ impl ScopedFunctionStack {
     }
 }
 
-#[cfg(debug_assertions)]
+#[cfg(all(debug_assertions, not(wasm_nothreads)))]
 thread_local! {
     static ERROR_CONTEXT_STACK: RefCell<ScopedFunctionStack> = const {
         RefCell::new(ScopedFunctionStack { functions: Vec::new() })
@@ -320,9 +320,9 @@ thread_local! {
 
 // Value may return `None`, even from panic hook, if called from a non-Godot thread.
 pub fn get_gdext_panic_context() -> Option<String> {
-    #[cfg(debug_assertions)]
+    #[cfg(all(debug_assertions, not(wasm_nothreads)))]
     return ERROR_CONTEXT_STACK.with(|cell| cell.borrow().get_last());
-    #[cfg(not(debug_assertions))]
+    #[cfg(not(all(debug_assertions, not(wasm_nothreads))))]
     None
 }
 
@@ -337,14 +337,14 @@ where
     E: Fn() -> String,
     F: FnOnce() -> R + std::panic::UnwindSafe,
 {
-    #[cfg(debug_assertions)]
+    #[cfg(all(debug_assertions, not(wasm_nothreads)))]
     ERROR_CONTEXT_STACK.with(|cell| unsafe {
         // SAFETY: &error_context is valid for lifetime of function, and is removed from LAST_ERROR_CONTEXT before end of function.
         cell.borrow_mut().push_function(&error_context)
     });
     let result =
         std::panic::catch_unwind(code).map_err(|payload| extract_panic_message(payload.as_ref()));
-    #[cfg(debug_assertions)]
+    #[cfg(all(debug_assertions, not(wasm_nothreads)))]
     ERROR_CONTEXT_STACK.with(|cell| cell.borrow_mut().pop_function());
     result
 }

godot-core/src/task/async_runtime.rs

@@ -55,6 +55,7 @@ pub fn spawn(future: impl Future<Output = ()> + 'static) -> TaskHandle {
     // By limiting async tasks to the main thread we can redirect all signal callbacks back to the main thread via `call_deferred`.
     //
     // Once thread-safe futures are possible the restriction can be lifted.
+    #[cfg(not(wasm_nothreads))]
     assert!(
         crate::init::is_main_thread(),
         "godot_task() can only be used on the main thread"