(api-break) remove the NothingLeft exception

README.md

@@ -35,18 +35,18 @@ produced C
 consumed C
 ```
 
-``consumer()`` can be written in more primitive way:
+The ``consumer()`` above can be written in more primitive way:
 
 ```python
-from asynckivy_ext.queue import Closed, NothingLeft
+from asynckivy_ext.queue import Closed
 
 
 async def consumer(q):
     try:
         while True:
             c = await q.get()
             print('consumed', c)
-    except (Closed, NothingLeft):
+    except Closed:
         pass
 ```
 

src/asynckivy_ext/queue.py

@@ -1,5 +1,5 @@
 __all__ = (
-    'QueueException', 'WouldBlock', 'Closed', 'NothingLeft',
+    'QueueException', 'WouldBlock', 'Closed',
     'Queue', 'Order', 'QueueState',
     )
 import typing as T
@@ -53,13 +53,10 @@ class Closed(QueueException):
     * one tries to get an item from a queue that is in the ``CLOSED`` state.
     * one tries to put an item into a queue that is in the ``CLOSED`` state.
     * one tries to put an item into a queue that is in the ``HALF_CLOSED`` state.
+    * one tries to get an item from an **empty** queue that is in the ``HALF_CLOSED`` state.
     '''
 
 
-class NothingLeft(QueueException):
-    '''Occurs when one tries to get an item from an empty queue that is in the ``HALF_CLOSED`` state. '''
-
-
 Item = T.Any
 Order = T.Literal['fifo', 'lifo', 'small-first']
 
@@ -131,7 +128,7 @@ def get(self) -> T.Awaitable[Item]:
         if self._state is QueueState.CLOSED:
             raise Closed
         if self._state is QueueState.HALF_CLOSED and self.is_empty:
-            raise NothingLeft
+            raise Closed
         self._trigger_consume()
         task = (yield _current_task)[0][0]  # 本来は except-Cancelled節に置きたい文だが、そこでは yield が使えないので仕方がない
         try:
@@ -145,7 +142,7 @@ def get_nowait(self) -> Item:
             raise Closed
         if self.is_empty:
             if self._state is QueueState.HALF_CLOSED:
-                raise NothingLeft
+                raise Closed
             raise WouldBlock
         self._trigger_consume()
         return self._c_get()
@@ -181,14 +178,13 @@ def half_close(self):
         pop_putter = self._pop_putter
         pop_getter = self._pop_getter
         C = Closed
-        NL = NothingLeft
 
         while (putter := pop_putter()[0]) is not None:
             putter._throw_exc(C)
         if not self.is_empty:
             return
         while (getter := pop_getter()) is not None:
-            getter._throw_exc(NL)
+            getter._throw_exc(C)
 
     def close(self):
         '''
@@ -214,7 +210,7 @@ async def __aiter__(self):
         try:
             while True:
                 yield await self.get()
-        except (NothingLeft, Closed):
+        except Closed:
             pass
 
     def _consume(self, dt):
@@ -225,7 +221,7 @@ def _consume(self, dt):
         pop_getter = self._pop_getter
         c_put = self._c_put
         c_get = self._c_get
-        NL = NothingLeft
+        Closed_ = Closed
         HALF_CLOSED = QueueState.HALF_CLOSED
 
         while True:
@@ -245,7 +241,7 @@ def _consume(self, dt):
             else:
                 if self._state is HALF_CLOSED:
                     while (getter := pop_getter()) is not None:
-                        getter._throw_exc(NL)
+                        getter._throw_exc(Closed_)
             if (not putters) or self.is_full:
                 break
         self._trigger_consume.cancel()

tests/test_queue.py

@@ -47,15 +47,10 @@ def test_put_to_closed_queue(capacity, close, nowait):
 @p('nowait', [True, False, ])
 def test_get_to_closed_queue(capacity, close, nowait):
     import asynckivy as ak
-    from asynckivy_ext.queue import Queue, Closed, NothingLeft
+    from asynckivy_ext.queue import Queue, Closed
     q = Queue(capacity=capacity)
-    if close:
-        q.close()
-        exc = Closed
-    else:
-        q.half_close()
-        exc = NothingLeft
-    with pytest.raises(exc):
+    q.close() if close else q.half_close()
+    with pytest.raises(Closed):
         q.get_nowait() if nowait else ak.start(q.get())
 
 
@@ -176,13 +171,13 @@ async def consumer(q):
 @p_capacity2
 def test_close_a_queue_while_it_holding_putters_and_getters(n_producers, n_consumers, close, capacity):
     import asynckivy as ak
-    from asynckivy_ext.queue import Queue, Closed, NothingLeft
+    from asynckivy_ext.queue import Queue, Closed
 
     async def producer(q):
         with pytest.raises(Closed):
             await q.put(None)
     async def consumer(q):
-        with pytest.raises(Closed if close else NothingLeft):
+        with pytest.raises(Closed):
             await q.get()
 
     q = Queue(capacity=capacity)
@@ -274,7 +269,6 @@ def test_various_statistics_nowait(order):
 
 @p_capacity
 def test_get_nowait_while_there_are_no_putters_and_no_items(capacity):
-    import asynckivy as ak
     from asynckivy_ext.queue import Queue, WouldBlock
     q = Queue(capacity=capacity)
     with pytest.raises(WouldBlock):
@@ -340,7 +334,7 @@ def test_put_nowait_to_unbounded_queue_that_has_a_getter():
 @p_capacity2
 def test_putter_triggers_close(kivy_clock, close, capacity):
     import asynckivy as ak
-    from asynckivy_ext.queue import Queue, Closed, NothingLeft
+    from asynckivy_ext.queue import Queue, Closed
 
     async def producer1(q):
         await q.put('A')
@@ -355,8 +349,7 @@ async def consumer1(q):
         else:
             assert await q.get() == 'A'
     async def consumer2(q):
-        exc = Closed if close else NothingLeft
-        with pytest.raises(exc):
+        with pytest.raises(Closed):
             await q.get()
 
     q = Queue(capacity=capacity)
@@ -379,7 +372,7 @@ async def consumer2(q):
 @p_capacity2
 def test_getter_triggers_close(kivy_clock, close, capacity):
     import asynckivy as ak
-    from asynckivy_ext.queue import Queue, Closed, NothingLeft
+    from asynckivy_ext.queue import Queue, Closed
 
     async def producer1(q):
         await q.put('A')
@@ -397,7 +390,7 @@ async def consumer2(q):
             with pytest.raises(Closed):
                 await q.get()
         elif capacity is not None and capacity < 2:
-            with pytest.raises(NothingLeft):
+            with pytest.raises(Closed):
                 await q.get()
         else:
             assert await q.get() == 'B'