fix record io bug

src/record_io.js

@@ -154,8 +154,10 @@ const make_patched_method = (original, name, use_context) => {
            )
       ){
         cxt.io_trace_is_replay_aborted = true
-        // Try to finish fast
+        cxt.io_trace_abort_replay()
-        // TODO invoke callback to notify that code must be restarted?
+        // throw error to prevent further code execution. It
+        // is not necesseary, becuase execution would not have
+        // any effects anyway
         const error = new Error('io replay aborted')
         error.__ignore = true
         throw error
@@ -188,7 +190,7 @@ const make_patched_method = (original, name, use_context) => {
             const next_event = cxt.io_trace[cxt.io_trace_index]
             if(next_event.type == 'call') {
               cxt.io_trace_is_replay_aborted = true
-              // TODO reject? Test for never resolved
+              cxt.io_trace_abort_replay()
             } else {
               while(
                 cxt.io_trace_index < cxt.io_trace.length 

src/runtime.js

@@ -29,9 +29,18 @@ const gen_to_promise = gen_fn => {
   }
 }
 
+const make_promise_with_rejector = cxt => {
+  let rejector
+  const p = new cxt.window.Promise(r => rejector = r)
+  return [p, rejector]
+}
+
 const do_run = function*(module_fns, cxt, io_trace){
   let calltree
 
+  const [replay_aborted_promise, io_trace_abort_replay] = 
+    make_promise_with_rejector(cxt)
+
   cxt = (io_trace == null || io_trace.length == 0)
     // TODO group all io_trace_ properties to single object?
     ? {...cxt,
@@ -46,32 +55,38 @@ const do_run = function*(module_fns, cxt, io_trace){
       // Map of (index in io_trace) -> resolve
       io_trace_resolvers: new Map(),
       io_trace_index: 0,
+      io_trace_abort_replay,
     }
 
   apply_promise_patch(cxt)
   set_current_context(cxt)
 
   for(let {module, fn} of module_fns) {
-     cxt.found_call = null
+    cxt.found_call = null
-     cxt.children = null
+    cxt.children = null
-     calltree = {
+    calltree = {
-       toplevel: true, 
+      toplevel: true, 
-       module,
+      module,
-       id: cxt.call_counter++
+      id: cxt.call_counter++
-     }
+    }
 
-     try {
+    try {
-       cxt.modules[module] = {}
+      cxt.modules[module] = {}
-       yield fn(cxt, __trace, __trace_call, __do_await)
+      const result = fn(cxt, __trace, __trace_call, __do_await)
-       calltree.ok = true
+      if(result instanceof cxt.window.Promise) {
-     } catch(error) {
+        yield cxt.window.Promise.race([replay_aborted_promise, result])
-       calltree.ok = false
+      } else {
-       calltree.error = error
+        yield result
-     }
+      }
-     calltree.children = cxt.children
+      calltree.ok = true
-     if(!calltree.ok) {
+    } catch(error) {
-       break
+      calltree.ok = false
-     }
+      calltree.error = error
+    }
+    calltree.children = cxt.children
+    if(!calltree.ok) {
+      break
+    }
   }
 
   cxt.is_recording_deferred_calls = true

test/test.js

@@ -3416,4 +3416,28 @@ const y = x()`
       'object',
     )
   }),
+
+  test('record io hangs bug', async () => {
+    patch_builtin(
+      'fetch', 
+      () => new Promise(resolve => original_setTimeout(resolve, 0))
+    )
+
+    const code = `
+      const p = fetch('')
+      Math.random()
+      await p
+    `
+
+    const i = await test_initial_state_async(code)
+
+    assert_equal(i.io_trace.length, 3)
+
+    const next_code = `await fetch('')`
+
+    const state = await command_input_async(i, next_code, 0)
+    assert_equal(state.io_trace.length, 2)
+
+    patch_builtin('fetch', null)
+  }),
 ]