Add warning log for failed tries.

PiperOrigin-RevId: 630604504

edward2/maps.py

@@ -38,7 +38,7 @@ def robust_map(
     max_workers: int | None = ...,
     raise_error: Literal[False] = ...,
     retry_exception_types: list[type[Exception]] | None = ...,
-) -> Sequence[U | V]:
+) -> list[U | V]:
   ...
 
 
@@ -52,7 +52,7 @@ def robust_map(
     max_workers: int | None = ...,
     raise_error: Literal[True] = ...,
     retry_exception_types: list[type[Exception]] | None = ...,
-) -> Sequence[U]:
+) -> list[U]:
   ...
 
 
@@ -66,7 +66,7 @@ def robust_map(
     max_workers: int | None = None,
     raise_error: bool = False,
     retry_exception_types: list[type[Exception]] | None = None,
-) -> Sequence[U | V]:
+) -> list[U | V]:
   """Maps a function to inputs using a threadpool.
 
   The map supports exception handling, retries with exponential backoff, and
@@ -107,12 +107,18 @@ def robust_map(
     fn_with_backoff = tenacity.retry(
         retry=retry,
         wait=tenacity.wait_random_exponential(min=1, max=30),
+        before_sleep=tenacity.before_sleep_log(
+            logging.get_absl_logger(), logging.WARNING
+        ),
     )(fn)
   else:
     fn_with_backoff = tenacity.retry(
         retry=retry,
         wait=tenacity.wait_random_exponential(min=1, max=30),
         stop=tenacity.stop_after_attempt(max_retries + 1),
+        before_sleep=tenacity.before_sleep_log(
+            logging.get_absl_logger(), logging.WARNING
+        ),
     )(fn)
   if index_to_output is None:
     index_to_output = {}