From 1a6b20dd788113bfa93a6e396932453b4e82bf49 Mon Sep 17 00:00:00 2001
From: theMackabu <theMackabu@gmail.com>
Date: Wed, 28 Jan 2026 23:57:06 -0800
Subject: [PATCH] add coroutine settlement and suspension handling

---
 src/sugar.c                          | 41 +++++++++++++------
 tests/test_async_await_microtask.cjs | 59 ++++++++++++++++++++++++++++
 2 files changed, 88 insertions(+), 12 deletions(-)
 create mode 100644 tests/test_async_await_microtask.cjs

diff --git a/src/sugar.c b/src/sugar.c
index c3eb895..ccf6eaa 100644
--- a/src/sugar.c
+++ b/src/sugar.c
@@ -255,6 +255,27 @@ jsval_t start_async_in_coroutine(struct js *js, const char *code, size_t code_le
   return promise;
 }
 
+static inline void settle_coroutine(coroutine_t *coro, jsval_t *args, int nargs, bool is_error) {
+  coro->result = nargs > 0 ? args[0] : js_mkundef();
+  coro->is_settled = true;
+  coro->is_error = is_error;
+  coro->is_ready = true;
+}
+
+static void resume_coroutine_if_suspended(struct js *js, coroutine_t *coro) {
+  if (!coro || !coro->mco || mco_status(coro->mco) != MCO_SUSPENDED) return;
+
+  remove_coroutine(coro);
+  coro_saved_state_t saved = coro_enter(js, coro);
+  mco_result res = mco_resume(coro->mco);
+  coro_leave(js, coro, saved);
+
+  if (res == MCO_SUCCESS && mco_status(coro->mco) != MCO_DEAD) {
+    coro->is_ready = false;
+    enqueue_coroutine(coro);
+  } else free_coroutine(coro);
+}
+
 jsval_t resume_coroutine_wrapper(struct js *js, jsval_t *args, int nargs) {
   jsval_t me = js->current_func;
   jsval_t coro_val = js_get_slot(js, me, SLOT_CORO);
@@ -262,12 +283,10 @@ jsval_t resume_coroutine_wrapper(struct js *js, jsval_t *args, int nargs) {
   
   coroutine_t *coro = (coroutine_t *)(uintptr_t)tod(coro_val);
   if (!coro) return js_mkundef();
-  
-  coro->result = nargs > 0 ? args[0] : js_mkundef();
-  coro->is_settled = true;
-  coro->is_error = false;
-  coro->is_ready = true;
-  
+
+  settle_coroutine(coro, args, nargs, false);
+  resume_coroutine_if_suspended(js, coro);
+
   return js_mkundef();
 }
 
@@ -279,11 +298,9 @@ jsval_t reject_coroutine_wrapper(struct js *js, jsval_t *args, int nargs) {
   
   coroutine_t *coro = (coroutine_t *)(uintptr_t)tod(coro_val);
   if (!coro) return js_mkundef();
-  
-  coro->result = nargs > 0 ? args[0] : js_mkundef();
-  coro->is_settled = true;
-  coro->is_error = true;
-  coro->is_ready = true;
-  
+
+  settle_coroutine(coro, args, nargs, true);
+  resume_coroutine_if_suspended(js, coro);
+
   return js_mkundef();
 }
diff --git a/tests/test_async_await_microtask.cjs b/tests/test_async_await_microtask.cjs
new file mode 100644
index 0000000..625d2f8
--- /dev/null
+++ b/tests/test_async_await_microtask.cjs
@@ -0,0 +1,59 @@
+var jobQueue = [];
+
+function setTimeout(cb, time, cbarg) {
+  var speedup = 10;
+  var runTime = Date.now() + time / speedup;
+  if (!jobQueue[runTime]) {
+    jobQueue[runTime] = [];
+  }
+  jobQueue[runTime].push(function () {
+    cb(cbarg);
+  });
+}
+
+function flushQueue() {
+  var curTime = Date.now();
+  var empty = true;
+  for (var runTime in jobQueue) {
+    empty = false;
+    if (curTime >= runTime) {
+      var jobs = jobQueue[runTime];
+      delete jobQueue[runTime];
+      jobs.forEach(function (job) {
+        job();
+      });
+    }
+  }
+  if (!empty) {
+    Promise.resolve().then(flushQueue);
+  }
+}
+
+function asyncTestPassed() {
+  console.log('test_async_await_microtask.cjs: OK');
+}
+
+function testCode() {
+  (async function () {
+    await Promise.resolve();
+    console.log('after');
+    var a1 = await new Promise(function (resolve) {
+      setTimeout(resolve, 800, 'foo');
+    });
+    var a2 = await new Promise(function (resolve) {
+      setTimeout(resolve, 800, 'bar');
+    });
+    if (a1 + a2 === 'foobar') {
+      asyncTestPassed();
+    } else {
+      console.log('test_async_await_microtask.cjs: FAIL');
+    }
+  })();
+}
+
+try {
+  testCode();
+  Promise.resolve().then(flushQueue);
+} catch (e) {
+  console.log('test_async_await_microtask.cjs: exception: ' + e);
+}
-- 
2.51.2