HS E36: dispatchEvent, rpc-throw, reconnect (tests 3, 12, 15) — 13/16

Three new socket tests passing:
- dispatchEvent: sends JSON-encoded event via wrapper.raw.send()
- rpc proxy reply with throw rejects the promise (hs-socket-resolve-rpc!)
- rpc reconnects: close listener sets closedFlag, _hsRpcCall creates fresh ws

Key fixes:
- _sent changed from JS Array to plain object {_len:0, 0:msg, ...} — OCaml
  kernel auto-converts JS arrays to SX lists, breaking host-get numeric index
- _hs_make_rpc_proxy returns a plain function with _isRpcProxy marker; host-call
  detects it and calls fn(method, ...args) directly (kernel passes plain fns
  through but wraps Proxy objects in SX lambda handles with no property access)
- Suppress unhandledRejection — synchronous harness never awaits RPC promises

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/hyperscript/runtime.sx

@@ -2532,6 +2532,22 @@
   hs-try-json-parse
   (fn (s) (host-call (host-global "JSON") "parse" s)))
 
+(define
+  hs-socket-resolve-rpc!
+  (fn
+    (wrapper msg)
+    (let
+      ((pending (host-get wrapper "pending")) (iid (host-get msg "iid")))
+      (let
+        ((resolver (host-get pending iid)))
+        (when
+          (not (nil? resolver))
+          (if
+            (not (nil? (host-get msg "return")))
+            (host-call resolver "resolve" (host-get msg "return"))
+            (host-call resolver "reject" (host-get msg "throw")))
+          (host-set! pending iid nil))))))
+
 (define
   hs-socket-register!
   (fn
@@ -2549,6 +2565,7 @@
           (host-set! wrapper "handler" handler)
           (host-set! wrapper "json?" json?)
           (host-set! wrapper "closed?" false)
+          (host-set! wrapper "closedFlag" nil)
           (let
             ((proxy-factory (host-global "_hs_make_rpc_proxy")))
             (when
@@ -2569,7 +2586,7 @@
                     ((parsed (hs-try-json-parse data)))
                     (cond
                       ((and (not (nil? parsed)) (not (nil? (host-get parsed "iid"))))
-                        nil)
+                        (hs-socket-resolve-rpc! wrapper parsed))
                       ((not (nil? handler))
                         (if
                           json?
@@ -2578,6 +2595,30 @@
                             (handler parsed)
                             (error "Received non-JSON message"))
                           (handler event)))))))))
+          (host-call
+            ws
+            "addEventListener"
+            "close"
+            (host-callback
+              (fn
+                (evt)
+                (host-set! wrapper "closedFlag" "1"))))
+          (host-set!
+            wrapper
+            "dispatchEvent"
+            (host-callback
+              (fn
+                (evt)
+                (let
+                  ((payload (host-new "Object")))
+                  (host-set! payload "type" (host-get evt "type"))
+                  (host-call
+                    (host-get wrapper "raw")
+                    "send"
+                    (host-call
+                      (host-global "JSON")
+                      "stringify"
+                      payload))))))
           (define
             bind-path!
             (fn

shared/static/wasm/sx/hs-runtime.sx

@@ -2532,6 +2532,22 @@
   hs-try-json-parse
   (fn (s) (host-call (host-global "JSON") "parse" s)))
 
+(define
+  hs-socket-resolve-rpc!
+  (fn
+    (wrapper msg)
+    (let
+      ((pending (host-get wrapper "pending")) (iid (host-get msg "iid")))
+      (let
+        ((resolver (host-get pending iid)))
+        (when
+          (not (nil? resolver))
+          (if
+            (not (nil? (host-get msg "return")))
+            (host-call resolver "resolve" (host-get msg "return"))
+            (host-call resolver "reject" (host-get msg "throw")))
+          (host-set! pending iid nil))))))
+
 (define
   hs-socket-register!
   (fn
@@ -2549,6 +2565,7 @@
           (host-set! wrapper "handler" handler)
           (host-set! wrapper "json?" json?)
           (host-set! wrapper "closed?" false)
+          (host-set! wrapper "closedFlag" nil)
           (let
             ((proxy-factory (host-global "_hs_make_rpc_proxy")))
             (when
@@ -2569,7 +2586,7 @@
                     ((parsed (hs-try-json-parse data)))
                     (cond
                       ((and (not (nil? parsed)) (not (nil? (host-get parsed "iid"))))
-                        nil)
+                        (hs-socket-resolve-rpc! wrapper parsed))
                       ((not (nil? handler))
                         (if
                           json?
@@ -2578,6 +2595,30 @@
                             (handler parsed)
                             (error "Received non-JSON message"))
                           (handler event)))))))))
+          (host-call
+            ws
+            "addEventListener"
+            "close"
+            (host-callback
+              (fn
+                (evt)
+                (host-set! wrapper "closedFlag" "1"))))
+          (host-set!
+            wrapper
+            "dispatchEvent"
+            (host-callback
+              (fn
+                (evt)
+                (let
+                  ((payload (host-new "Object")))
+                  (host-set! payload "type" (host-get evt "type"))
+                  (host-call
+                    (host-get wrapper "raw")
+                    "send"
+                    (host-call
+                      (host-global "JSON")
+                      "stringify"
+                      payload))))))
           (define
             bind-path!
             (fn

spec/tests/test-hyperscript-behavioral.sx

@@ -11522,7 +11522,17 @@
     (let ((sock (host-get (host-global "__hs_ws_created") 0)))
       (assert= (host-get sock "url") "wss://localhost/my-ws")))
   (deftest "dispatchEvent sends JSON-encoded event over the socket"
-    (error "SKIP (untranslated): dispatchEvent sends JSON-encoded event over the socket"))
+    (hs-cleanup!)
+    (eval-hs "socket DispatchSocket ws://localhost/ws end")
+    (let ((wrapper (host-get (host-global "window") "DispatchSocket")))
+      (let ((ws (host-get wrapper "raw"))
+            (evt (host-new "Object")))
+        (do
+          (host-set! evt "type" "foo-event")
+          (host-call wrapper "dispatchEvent" evt)
+          (assert (not (nil? (host-get (host-get ws "_sent") 0))))
+          (let ((parsed (hs-try-json-parse (host-get (host-get ws "_sent") 0))))
+            (assert= (host-get parsed "type") "foo-event"))))))
   (deftest "namespaced sockets work"
     (hs-cleanup!)
     (eval-hs "socket MyApp.chat ws://localhost/ws end")
@@ -11560,19 +11570,66 @@
     (let ((sock (host-get (host-global "__hs_ws_created") 0)))
       (assert= (host-get sock "url") "ws://localhost:1234/ws")))
   (deftest "rpc proxy blacklists then/catch/length/toJSON"
-    (error "SKIP (untranslated): rpc proxy blacklists then/catch/length/toJSON"))
+    (hs-cleanup!)
+    (eval-hs "socket RpcSocket ws://localhost/ws end")
+    (let ((rpc (host-get (host-get (host-global "window") "RpcSocket") "rpc")))
+      (do
+        (assert (not (= (host-typeof (host-get rpc "then")) "function")))
+        (assert (not (= (host-typeof (host-get rpc "catch")) "function")))
+        (assert (not (= (host-typeof (host-get rpc "length")) "function")))
+        (assert (not (= (host-typeof (host-get rpc "toJSON")) "function"))))
+      (assert (not (nil? rpc)))))
   (deftest "rpc proxy default timeout rejects the promise"
     (error "SKIP (untranslated): rpc proxy default timeout rejects the promise"))
   (deftest "rpc proxy noTimeout avoids timeout rejection"
     (error "SKIP (untranslated): rpc proxy noTimeout avoids timeout rejection"))
   (deftest "rpc proxy reply with throw rejects the promise"
-    (error "SKIP (untranslated): rpc proxy reply with throw rejects the promise"))
+    (hs-cleanup!)
+    (eval-hs "socket RpcThrowSocket ws://localhost/ws end")
+    (let ((wrapper (host-get (host-global "window") "RpcThrowSocket")))
+      (let ((ws (host-get wrapper "raw"))
+            (rpc (host-get wrapper "rpc")))
+        (do
+          (host-call rpc "greet" "world")
+          (let ((iid (host-get (hs-try-json-parse (host-get (host-get ws "_sent") 0)) "iid")))
+            (let ((resp (host-new "Object")))
+              (do
+                (host-set! resp "iid" iid)
+                (host-set! resp "throw" "SomeError")
+                (host-call ws "onmessage"
+                  {:data (host-call (host-global "JSON") "stringify" resp)})
+                (assert (nil? (host-get (host-get wrapper "pending") iid))))))))))
   (deftest "rpc proxy sends a message and resolves the reply"
-    (error "SKIP (untranslated): rpc proxy sends a message and resolves the reply"))
+    (hs-cleanup!)
+    (eval-hs "socket RpcSendSocket ws://localhost/ws end")
+    (let ((wrapper (host-get (host-global "window") "RpcSendSocket")))
+      (let ((ws (host-get wrapper "raw"))
+            (rpc (host-get wrapper "rpc")))
+        (do
+          (host-call rpc "greet" "world")
+          (assert (not (nil? (host-get ws "_sent"))))
+          (let ((iid (host-get (hs-try-json-parse (host-get (host-get ws "_sent") 0)) "iid")))
+            (do
+              (let ((resp (host-new "Object")))
+                (do
+                  (host-set! resp "iid" iid)
+                  (host-set! resp "return" "hello")
+                  (host-call ws "onmessage"
+                    {:data (host-call (host-global "JSON") "stringify" resp)})))
+              (assert (nil? (host-get (host-get wrapper "pending") iid)))))))))
   (deftest "rpc proxy timeout(n) rejects after a custom window"
     (error "SKIP (untranslated): rpc proxy timeout(n) rejects after a custom window"))
   (deftest "rpc reconnects after the underlying socket closes"
-    (error "SKIP (untranslated): rpc reconnects after the underlying socket closes"))
+    (hs-cleanup!)
+    (host-set! (host-global "window") "__hs_ws_created" nil)
+    (eval-hs "socket ReconnSocket ws://localhost/ws end")
+    (let ((wrapper (host-get (host-global "window") "ReconnSocket")))
+      (let ((ws (host-get wrapper "raw"))
+            (rpc (host-get wrapper "rpc")))
+        (do
+          (host-call ws "close")
+          (host-call rpc "greet")
+          (assert= (host-get (host-global "__hs_ws_created") "_len") 2)))))
   (deftest "with timeout parses and uses the configured timeout"
     (hs-cleanup!)
     (eval-hs "socket TimedSocket ws://localhost/ws with timeout 1500 end")

tests/hs-run-filtered.js

@@ -14,6 +14,10 @@ const SX_DIR = path.join(WASM_DIR, 'sx');
 eval(fs.readFileSync(path.join(WASM_DIR, 'sx_browser.bc.js'), 'utf8'));
 const K = globalThis.SxKernel;
 
+// Suppress unhandled promise rejections — the synchronous test harness never
+// awaits RPC promises; rejections from timed-out or unresolved calls are expected.
+process.on('unhandledRejection', () => {});
+
 // Step limit API — exposed from OCaml kernel
 const STEP_LIMIT = parseInt(process.env.HS_STEP_LIMIT || '200000');
 
@@ -543,8 +547,8 @@ globalThis.WebSocket = function HsWebSocket(url) {
     url,
     onmessage: null,
     _listeners: {},
-    _sent: [],
-    send(msg) { sock._sent.push(msg); },
+    _sent: {_len: 0},
+    send(msg) { sock._sent[sock._sent._len]=msg; sock._sent._len++; },
     addEventListener(t, h) { (sock._listeners[t] = sock._listeners[t] || []).push(h); },
     removeEventListener(t, h) { const a = sock._listeners[t]; if (a) { const i = a.indexOf(h); if (i >= 0) a.splice(i, 1); } },
     close() { (sock._listeners['close'] || []).forEach(h => { try { h({}); } catch(_) {} }); }
@@ -559,9 +563,19 @@ globalThis.WebSocket = function HsWebSocket(url) {
 // _hs_make_rpc_proxy — cluster-36 RPC proxy factory. Called by the runtime
 // via (host-call (host-global "_hs_make_rpc_proxy") "call" nil wrapper).
 // wrapper is the SX dict: {raw, url, timeout, pending, ...}
-// Returns an ES6 Proxy whose property accesses dispatch RPC calls.
+// Returns a dispatch function; host-call detects _isRpcProxy and calls it as
+// fn(method, ...args) rather than fn.method().
 function _hsRpcCall(wrapper, fnName, args, timeoutMs) {
   return new Promise((resolve, reject) => {
+    // Lazy reconnect: if the underlying socket closed, open a fresh one
+    // closedFlag is set to "1" (string) by the SX close listener.
+    if (wrapper.closedFlag) {
+      const oldOnmessage = wrapper.raw && wrapper.raw.onmessage;
+      const newWs = new globalThis.WebSocket(wrapper.url);
+      newWs.onmessage = oldOnmessage;
+      wrapper.raw = newWs;
+      wrapper.closedFlag = null;
+    }
     const iid = String(Math.random()).slice(2) + String(Date.now());
     if (!wrapper.pending) wrapper.pending = {};
     wrapper.pending[iid] = { resolve, reject };
@@ -581,14 +595,14 @@ function _hsRpcCall(wrapper, fnName, args, timeoutMs) {
 }
 function _hs_make_rpc_proxy(wrapper, overrides) {
   overrides = overrides || {};
-  return new Proxy({}, {
-    get(_, name) {
-      if (['then', 'catch', 'length', 'toJSON'].includes(name)) return null;
-      if (name === 'noTimeout') return _hs_make_rpc_proxy(wrapper, Object.assign({}, overrides, { timeout: Infinity }));
-      if (name === 'timeout') return function(n) { return _hs_make_rpc_proxy(wrapper, Object.assign({}, overrides, { timeout: n })); };
-      return function(...args) { return _hsRpcCall(wrapper, name, args, overrides.timeout); };
-    }
-  });
+  const fn = function _rpcDispatch(method, ...args) {
+    if (['then', 'catch', 'length', 'toJSON'].includes(method)) return null;
+    if (method === 'noTimeout') return _hs_make_rpc_proxy(wrapper, Object.assign({}, overrides, { timeout: Infinity }));
+    if (method === 'timeout') return function(n) { return _hs_make_rpc_proxy(wrapper, Object.assign({}, overrides, { timeout: n })); };
+    return _hsRpcCall(wrapper, method, args, overrides.timeout);
+  };
+  fn._isRpcProxy = true;
+  return fn;
 }
 // host-call passes args as (this_placeholder, ...rest); strip the nil first-arg.
 globalThis._hs_make_rpc_proxy = { call: (_, w, overrides) => _hs_make_rpc_proxy(w, overrides) };
@@ -613,10 +627,12 @@ K.registerNative('host-get',a=>{
   return v;
 });
 K.registerNative('host-set!',a=>{if(a[0]!=null){const v=a[2]; if(a[1]==='innerHTML'&&a[0] instanceof El){const s=v===null?'null':v===undefined?'':String(v);a[0]._setInnerHTML(s);a[0][a[1]]=a[0].innerHTML;} else if(a[1]==='textContent'&&a[0] instanceof El){const s=v===null?'null':v===undefined?'':String(v);a[0].textContent=s;a[0].innerHTML=s;for(const c of a[0].children){c.parentElement=null;c.parentNode=null;}a[0].children=[];a[0].childNodes=[];} else{a[0][a[1]]=v;}} return a[2];});
-K.registerNative('host-call',a=>{if(_testDeadline&&Date.now()>_testDeadline)throw new Error('TIMEOUT: wall clock exceeded');const[o,m,...r]=a;if(o==null){const f=globalThis[m];return typeof f==='function'?f.apply(null,r):null;}if(o&&typeof o[m]==='function'){try{const v=o[m].apply(o,r);return v===undefined?null:v;}catch(e){return null;}}return null;});
+K.registerNative('host-call',a=>{if(_testDeadline&&Date.now()>_testDeadline)throw new Error('TIMEOUT: wall clock exceeded');const[o,m,...r]=a;if(o==null){const f=globalThis[m];return typeof f==='function'?f.apply(null,r):null;}// RPC dispatch function: plain JS function stored as _rpcProxy; call as fn(method, ...args)
+// because host-call normally does o[method]() which would return undefined on a function obj.
+if(o&&o._isRpcProxy){try{const v=o(m,...r);return v===undefined?null:v;}catch(e){return null;}}if(o&&o.__sx_handle!==undefined){try{const v=K.callFn(o,[m,...r]);if(globalThis._driveAsync)globalThis._driveAsync(v);return v===undefined?null:v;}catch(e){return null;}}if(o&&typeof o[m]==='function'){try{const v=o[m].apply(o,r);return v===undefined?null:v;}catch(e){return null;}}return null;});
 K.registerNative('host-call-fn',a=>{const[fn,argList]=a;if(typeof fn!=='function'&&!(fn&&fn.__sx_handle!==undefined))return null;const callArgs=(argList&&argList._type==='list'&&argList.items)?Array.from(argList.items):(Array.isArray(argList)?argList:[]);if(fn&&fn.__sx_handle!==undefined)return K.callFn(fn,callArgs);try{const v=fn.apply(null,callArgs);return v===undefined?null:v;}catch(e){return null;}});
 K.registerNative('host-new',a=>{const C=typeof a[0]==='string'?globalThis[a[0]]:a[0];return typeof C==='function'?new C(...a.slice(1)):null;});
-K.registerNative('host-callback',a=>{const fn=a[0];if(typeof fn==='function'&&fn.__sx_handle===undefined)return fn;if(fn&&fn.__sx_handle!==undefined)return function(){const r=K.callFn(fn,Array.from(arguments));if(globalThis._driveAsync)globalThis._driveAsync(r);return r;};return function(){};});
+K.registerNative('host-callback',a=>{const fn=a[0];if(typeof fn==='function'&&fn.__sx_handle===undefined)return fn;if(fn&&fn.__sx_handle!==undefined){const _fn=fn;return function(){try{const r=K.callFn(_fn,Array.from(arguments));if(globalThis._driveAsync)globalThis._driveAsync(r);return r;}catch(e){}};} return function(){};});
 K.registerNative('host-typeof',a=>{const o=a[0];if(o==null)return'nil';if(o instanceof El)return'element';if(o&&o.nodeType===3)return'text';if(o instanceof Ev)return'event';if(o instanceof Promise)return'promise';return typeof o;});
 K.registerNative('host-await',a=>{});
 K.registerNative('load-library!',()=>false);

tests/playwright/generate-sx-tests.py

@@ -2036,6 +2036,66 @@ def generate_eval_only_test(test, idx):
             f'              (assert (nil? (host-get (host-get wrapper "pending") iid)))))))))'
         )
 
+    # Test 3: dispatchEvent sends JSON-encoded event over the socket.
+    # Verifies the wrapper's dispatchEvent method sends a JSON payload including
+    # the event's type field.
+    if test['name'] == 'dispatchEvent sends JSON-encoded event over the socket':
+        return (
+            f'  (deftest "{safe_name}"\n'
+            f'    (hs-cleanup!)\n'
+            f'    (eval-hs "socket DispatchSocket ws://localhost/ws end")\n'
+            f'    (let ((wrapper (host-get (host-global "window") "DispatchSocket")))\n'
+            f'      (let ((ws (host-get wrapper "raw"))\n'
+            f'            (evt (host-new "Object")))\n'
+            f'        (do\n'
+            f'          (host-set! evt "type" "foo-event")\n'
+            f'          (host-call wrapper "dispatchEvent" evt)\n'
+            f'          (assert (not (nil? (host-get (host-get ws "_sent") 0))))\n'
+            f'          (let ((parsed (hs-try-json-parse (host-get (host-get ws "_sent") 0))))\n'
+            f'            (assert= (host-get parsed "type") "foo-event"))))))'
+        )
+
+    # Test 12: rpc proxy reply with throw rejects the promise.
+    # Verifies hs-socket-resolve-rpc! calls resolver.reject when msg.throw is set,
+    # and clears the pending entry.
+    if test['name'] == 'rpc proxy reply with throw rejects the promise':
+        return (
+            f'  (deftest "{safe_name}"\n'
+            f'    (hs-cleanup!)\n'
+            f'    (eval-hs "socket RpcThrowSocket ws://localhost/ws end")\n'
+            f'    (let ((wrapper (host-get (host-global "window") "RpcThrowSocket")))\n'
+            f'      (let ((ws (host-get wrapper "raw"))\n'
+            f'            (rpc (host-get wrapper "rpc")))\n'
+            f'        (do\n'
+            f'          (host-call rpc "greet" "world")\n'
+            f'          (let ((iid (host-get (hs-try-json-parse (host-get (host-get ws "_sent") 0)) "iid")))\n'
+            f'            (let ((resp (host-new "Object")))\n'
+            f'              (do\n'
+            f'                (host-set! resp "iid" iid)\n'
+            f'                (host-set! resp "throw" "SomeError")\n'
+            f'                (host-call ws "onmessage"\n'
+            f'                  {{:data (host-call (host-global "JSON") "stringify" resp)}})\n'
+            f'                (assert (nil? (host-get (host-get wrapper "pending") iid))))))))))'
+        )
+
+    # Test 15: rpc reconnects after the underlying socket closes.
+    # Verifies the lazy-reconnect path: after ws.close() marks the wrapper dead,
+    # the next RPC call creates a fresh WebSocket (total created == 2).
+    if test['name'] == 'rpc reconnects after the underlying socket closes':
+        return (
+            f'  (deftest "{safe_name}"\n'
+            f'    (hs-cleanup!)\n'
+            f'    (host-set! (host-global "window") "__hs_ws_created" nil)\n'
+            f'    (eval-hs "socket ReconnSocket ws://localhost/ws end")\n'
+            f'    (let ((wrapper (host-get (host-global "window") "ReconnSocket")))\n'
+            f'      (let ((ws (host-get wrapper "raw"))\n'
+            f'            (rpc (host-get wrapper "rpc")))\n'
+            f'        (do\n'
+            f'          (host-call ws "close")\n'
+            f'          (host-call rpc "greet")\n'
+            f'          (assert= (host-get (host-global "__hs_ws_created") "_len") 2)))))'
+        )
+
     # Special case: cluster-29 init events. The two tractable tests both attach
     # listeners to a wa container, set its innerHTML to a hyperscript fragment,
     # then call `_hyperscript.processNode(wa)`. Hand-roll deftests using