More cleanup, yey!

[python_utils.git] / smart_future.py

diff --git a/smart_future.py b/smart_future.py
index c96c5a712d9f8d829eb73a21082f2ffbc0f41d48..9aa68f38a5396953636e257032542f9d07533225 100644 (file)
--- a/smart_future.py
+++ b/smart_future.py
@@ -1,18 +1,24 @@
 #!/usr/bin/env python3
 
+"""A future that can be treated like the result that it contains and
+will not block until it is used.  At that point, if the underlying
+value is not yet available, it will block until it becomes
+available."""
+
 from __future__ import annotations
+
 import concurrent
 import concurrent.futures as fut
 import logging
-import traceback
-from typing import Callable, List, TypeVar
+from typing import Callable, List, Set, TypeVar
 
 from overrides import overrides
 
+import id_generator
+
 # This module is commonly used by others in here and should avoid
 # taking any unnecessary dependencies back on them.
 from deferred_operand import DeferredOperand
-import id_generator
 
 logger = logging.getLogger(__name__)
 
@@ -27,10 +33,12 @@ def wait_any(
 ):
     real_futures = []
     smart_future_by_real_future = {}
-    completed_futures = set()
-    for _ in futures:
-        real_futures.append(_.wrapped_future)
-        smart_future_by_real_future[_.wrapped_future] = _
+    completed_futures: Set[fut.Future] = set()
+    for x in futures:
+        assert isinstance(x, SmartFuture)
+        real_futures.append(x.wrapped_future)
+        smart_future_by_real_future[x.wrapped_future] = x
+
     while len(completed_futures) != len(real_futures):
         newly_completed_futures = concurrent.futures.as_completed(real_futures)
         for f in newly_completed_futures:
@@ -40,12 +48,12 @@ def wait_any(
             if log_exceptions and not f.cancelled():
                 exception = f.exception()
                 if exception is not None:
+                    logger.warning('Future 0x%x raised an unhandled exception and exited.', id(f))
                     logger.exception(exception)
-                    traceback.print_tb(exception.__traceback__)
+                    raise exception
             yield smart_future_by_real_future[f]
     if callback is not None:
         callback()
-    return
 
 
 def wait_all(
@@ -53,7 +61,11 @@ def wait_all(
     *,
     log_exceptions: bool = True,
 ) -> None:
-    real_futures = [x.wrapped_future for x in futures]
+    real_futures = []
+    for x in futures:
+        assert isinstance(x, SmartFuture)
+        real_futures.append(x.wrapped_future)
+
     (done, not_done) = concurrent.futures.wait(
         real_futures, timeout=None, return_when=concurrent.futures.ALL_COMPLETED
     )
@@ -62,8 +74,9 @@ def wait_all(
             if not f.cancelled():
                 exception = f.exception()
                 if exception is not None:
+                    logger.warning('Future 0x%x raised an unhandled exception and exited.', id(f))
                     logger.exception(exception)
-                    traceback.print_tb(exception.__traceback__)
+                    raise exception
     assert len(done) == len(real_futures)
     assert len(not_done) == 0
 
@@ -77,6 +90,7 @@ class SmartFuture(DeferredOperand):
     """
 
     def __init__(self, wrapped_future: fut.Future) -> None:
+        assert isinstance(wrapped_future, fut.Future)
         self.wrapped_future = wrapped_future
         self.id = id_generator.get("smart_future_id")
 
@@ -89,5 +103,5 @@ class SmartFuture(DeferredOperand):
     # You shouldn't have to call this; instead, have a look at defining a
     # method on DeferredOperand base class.
     @overrides
-    def _resolve(self, *, timeout=None) -> T:
+    def _resolve(self, timeout=None) -> T:
         return self.wrapped_future.result(timeout)