Fixed issue with sleeping and I/O

aiosched/kernel.py

@@ -220,7 +220,16 @@ class FIFOKernel:
         for key, _ in self.selector.select(timeout):
             key.data: dict[int, Task]
             for task in key.data.values():
-                self.run_ready.append(task)  # Resource ready? Schedule its task
+                # Since we don't unschedule I/O
+                # resources after every operation,
+                # we may hold on to a socket while
+                # its owner task is sleeping on some
+                # synchronization primitive: if we
+                # rescheduled it now, it would cause
+                # all sort of nonsense! So we only
+                # schedule tasks waiting for I/O to happen
+                if task.state == TaskState.IO:
+                    self.run_ready.append(task)  # Resource ready? Schedule its task
         self.debugger.after_io(self.clock() - before_time)
 
     def awake_tasks(self):

aiosched/sync.py

@@ -223,7 +223,7 @@ class MemoryChannel(Channel):
         # We use a queue as our buffer
         self.buffer = Queue(maxsize=maxsize)
 
-    async def write(self, data: str):
+    async def write(self, data):
         """
         Writes data to the channel. Blocks if the internal
         queue is full until a spot is available. Does nothing
@@ -321,7 +321,7 @@ class NetworkChannel(Channel):
 
         if self.closed:
             return False
-        elif self.reader.fileno() == -1:
+        elif await self.reader.fileno() == -1:
             return False
         else:
             try:

tests/network_channel.py

@@ -1,7 +1,6 @@
 import aiosched
 
 
-
 async def producer(c: aiosched.NetworkChannel, n: int):
     print("[producer] Started")
     for i in range(n):
@@ -18,7 +17,9 @@ async def consumer(c: aiosched.NetworkChannel):
         while await c.pending():
             item = await c.read(1)
             print(f"[consumer] Received {item.decode()}")
-            # await aiosched.sleep(2)    # If you uncomment this, the except block will be triggered
+            # In this example, the consumer is twice as slow
+            # as the producer
+            await aiosched.sleep(1)
     except aiosched.errors.ResourceClosed:
         print("[consumer] Stream has been closed early!")
     print("[consumer] Done")
@@ -34,5 +35,5 @@ async def main(channel: aiosched.NetworkChannel, n: int):
 
 
 aiosched.run(
-    main, aiosched.NetworkChannel(), 5, debugger=()
+    main, aiosched.NetworkChannel(), 10, debugger=()
-)  # 2 is the max size of the channel
+)