fix(bindgen): bindgen runtime bugs

This commit contains runtime bugs reported by Wado compiler toolchain
developers (see wado-lang/wado#714). While the
original PR had a few changes that Jco isn't ready to take just yet,
there are many that are absolutely right for inclusion:

- waitable-set.wait missing suspending
- waitable-set.wait invalid waitForEvent() call
- missing intrinsic deps
- lowerFlatVariant empty payload crash

Co-Authored-By: FUJI Goro <g.psy.va@gmail.com>
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 3 people

crates/js-component-bindgen/src/intrinsics/lower.rs

@@ -542,14 +542,17 @@ impl LowerIntrinsic {
 
                             ctx.resultPtr = originalPtr + payloadOffset32;
 
-                            const payloadBytesWritten = lowerFn({{
-                                memory,
-                                realloc,
-                                vals: [val],
-                                storagePtr,
-                                storageLen,
-                                componentIdx,
-                            }});
+                            let payloadBytesWritten = 0;
+                            if (lowerFn) {{
+                                lowerFn({{
+                                    memory,
+                                    realloc,
+                                    vals: [val],
+                                    storagePtr,
+                                    storageLen,
+                                    componentIdx,
+                                }});
+                            }}
                             let bytesWritten = payloadOffset + payloadBytesWritten;
 
                             const rem = ctx.storagePtr % align32;

crates/js-component-bindgen/src/intrinsics/mod.rs

@@ -1213,6 +1213,9 @@ pub fn render_intrinsics(args: RenderIntrinsicsArgs) -> Source {
     if args
         .intrinsics
         .contains(&Intrinsic::Waitable(WaitableIntrinsic::WaitableSetPoll))
+        || args
+            .intrinsics
+            .contains(&Intrinsic::Waitable(WaitableIntrinsic::WaitableSetWait))
     {
         args.intrinsics
             .extend([&Intrinsic::Host(HostIntrinsic::StoreEventInComponentMemory)]);
@@ -1268,6 +1271,22 @@ pub fn render_intrinsics(args: RenderIntrinsicsArgs) -> Source {
         ]);
     }
 
+    if args
+        .intrinsics
+        .contains(&Intrinsic::Lower(LowerIntrinsic::LowerFlatResult))
+    {
+        args.intrinsics
+            .insert(Intrinsic::Lower(LowerIntrinsic::LowerFlatVariant));
+    }
+
+    if args
+        .intrinsics
+        .contains(&Intrinsic::Lower(LowerIntrinsic::LowerFlatOption))
+    {
+        args.intrinsics
+            .insert(Intrinsic::Lower(LowerIntrinsic::LowerFlatVariant));
+    }
+
     if args
         .intrinsics
         .contains(&Intrinsic::Lower(LowerIntrinsic::LowerFlatVariant))
@@ -1364,10 +1383,14 @@ pub fn render_intrinsics(args: RenderIntrinsicsArgs) -> Source {
     if args
         .intrinsics
         .contains(&Intrinsic::AsyncStream(AsyncStreamIntrinsic::StreamWrite))
+        || args
+            .intrinsics
+            .contains(&Intrinsic::AsyncStream(AsyncStreamIntrinsic::StreamRead))
     {
         args.intrinsics.extend([
             &Intrinsic::GlobalBufferManager,
             &Intrinsic::AsyncTask(AsyncTaskIntrinsic::AsyncBlockedConstant),
+            &Intrinsic::AsyncEventCodeEnum,
         ]);
     }
 

crates/js-component-bindgen/src/intrinsics/p3/async_stream.rs

@@ -1140,7 +1140,7 @@ impl AsyncStreamIntrinsic {
                     r#"
                     class {host_stream_class_name} {{
                         #componentIdx;
-                        #streamEndIdx;
+                        #streamEndWaitableIdx;
                         #streamTableIdx;
 
                         #payloadLiftFn;
@@ -1162,24 +1162,26 @@ impl AsyncStreamIntrinsic {
                             if (!args.payloadLowerFn) {{ throw new TypeError("missing payload lower fn"); }}
                             this.#payloadLowerFn = args.payloadLowerFn;
 
-                            if (args.streamEndIdx === undefined) {{ throw new Error("missing stream idx"); }}
+                            if (args.streamEndWaitableIdx === undefined) {{ throw new Error("missing stream idx"); }}
                             if (args.streamTableIdx === undefined) {{ throw new Error("missing stream table idx"); }}
-                            this.#streamEndIdx = args.streamEndIdx;
+                            this.#streamEndWaitableIdx = args.streamEndWaitableIdx;
                             this.#streamTableIdx = args.streamTableIdx;
 
                             this.#isUnitStream = args.isUnitStream;
                         }}
 
+                        setRep(r) {{ this.#rep = r; }}
+
                         createUserStream(args) {{
                            if (this.#userStream) {{ return this.#userStream; }}
                            if (this.#rep === null) {{ throw new Error("unexpectedly missing rep for host stream"); }}
 
                            const cstate = {get_or_create_async_state_fn}(this.#componentIdx);
                            if (!cstate) {{ throw new Error(`missing async state for component [${{this.#componentIdx}}]`); }}
 
-                           const streamEnd = cstate.getStreamEnd({{ tableIdx: this.#streamTableIdx, streamEndIdx: this.#streamEndIdx }});
+                           const streamEnd = cstate.getStreamEnd({{ tableIdx: this.#streamTableIdx, streamEndWaitableIdx: this.#streamEndWaitableIdx }});
                            if (!streamEnd) {{
-                               throw new Error(`missing stream [${{this.#streamEndIdx}}] (table [${{this.#streamTableIdx}}], component [${{this.#componentIdx}}]`);
+                               throw new Error(`missing stream [${{this.#streamEndWaitableIdx}}] (table [${{this.#streamTableIdx}}], component [${{this.#componentIdx}}]`);
                            }}
 
                             return new {external_stream_class}({{
@@ -1366,7 +1368,7 @@ impl AsyncStreamIntrinsic {
                         {debug_log_fn}('[{stream_new_from_lift_fn}()] args', {{ ctx }});
                         const {{
                             componentIdx,
-                            streamEndIdx,
+                            streamEndWaitableIdx,
                             streamTableIdx,
                             payloadLiftFn,
                             payloadTypeSize32,
@@ -1376,7 +1378,7 @@ impl AsyncStreamIntrinsic {
 
                         const stream = new {host_stream_class}({{
                             componentIdx,
-                            streamEndIdx,
+                            streamEndWaitableIdx,
                             streamTableIdx,
                             payloadLiftFn: payloadLiftFn,
                             payloadLowerFn: payloadLowerFn,

crates/js-component-bindgen/src/intrinsics/p3/waitable.rs

@@ -392,8 +392,9 @@ impl WaitableIntrinsic {
                             throw Error(`task component [${{task.componentIdx}}] !== executing component [${{componentIdx}}]`);
                         }}
 
-                        const event = await task.waitForEvent({{ waitableSetRep, isAsync }});
-                        return {store_event_in_component_memory_fn}(memory, task, event, resultPtr);
+                        const memory = getMemoryFn();
+                        const event = await task.waitUntil({{ waitableSetRep, readyFn: () => true, cancellable: false }});
+                        return {store_event_in_component_memory_fn}({{ memory, ptr: resultPtr, event }});
                     }}
                 "#));
             }

crates/js-component-bindgen/src/transpile_bindgen.rs

@@ -1202,12 +1202,12 @@ impl<'a> Instantiator<'a, '_> {
                 uwriteln!(
                     self.src.js,
                     r#"
-                    const trampoline{i} = {waitable_set_wait_fn}.bind(null, {{
+                    const trampoline{i} = new WebAssembly.Suspending({waitable_set_wait_fn}.bind(null, {{
                         componentIdx: {instance_idx},
                         isAsync: {async_},
                         memoryIdx: {memory_idx},
                         getMemoryFn: () => memory{memory_idx},
-                    }});
+                    }}));
                     "#,
                 );
             }