From a2841f71d8448d6dfe08feb2c27108967aceb4cf Mon Sep 17 00:00:00 2001
From: David Slater <davidslater@users.noreply.github.com>
Date: Thu, 9 Feb 2023 15:41:40 -0800
Subject: [PATCH 1/4] added new typing and changed error response

---
 backoff/_decorator.py | 20 ++++++++++++++++++--
 backoff/_typing.py    |  2 +-
 tests/test_typing.py  | 14 ++++++++++++++
 3 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/backoff/_decorator.py b/backoff/_decorator.py
index 77ed8c2..c281798 100644
--- a/backoff/_decorator.py
+++ b/backoff/_decorator.py
@@ -18,7 +18,7 @@
     _Jitterer,
     _MaybeCallable,
     _MaybeLogger,
-    _MaybeSequence,
+    _MaybeTuple,
     _Predicate,
     _WaitGenerator,
 )
@@ -120,8 +120,23 @@ def decorate(target):
     return decorate
 
 
+def _check_exception_type(exception: _MaybeTuple[Type[Exception]]) -> None:
+    """
+    Raise TypeError if exception is not a valid type, otherwise return None
+    """
+    if isinstance(exception, Type) and issubclass(exception, Exception):
+        return
+    if isinstance(exception, tuple) and all(isinstance(e, Type)
+            and issubclass(e, Exception) for e in exception):
+        return
+    raise TypeError(
+        f"exception '{exception}' of type {type(exception)} is not"
+        " an Exception type or a tuple of Exception types"
+    )
+
+
 def on_exception(wait_gen: _WaitGenerator,
-                 exception: _MaybeSequence[Type[Exception]],
+                 exception: _MaybeTuple[Type[Exception]],
                  *,
                  max_tries: Optional[_MaybeCallable[int]] = None,
                  max_time: Optional[_MaybeCallable[float]] = None,
@@ -180,6 +195,7 @@ def on_exception(wait_gen: _WaitGenerator,
             args will first be evaluated and their return values passed.
             This is useful for runtime configuration.
     """
+    _check_exception_type(exception)
     def decorate(target):
         nonlocal logger, on_success, on_backoff, on_giveup
 
diff --git a/backoff/_typing.py b/backoff/_typing.py
index 20446d4..cc9e6f5 100644
--- a/backoff/_typing.py
+++ b/backoff/_typing.py
@@ -39,6 +39,6 @@ class Details(_Details, total=False):
 _Jitterer = Callable[[float], float]
 _MaybeCallable = Union[T, Callable[[], T]]
 _MaybeLogger = Union[str, logging.Logger, None]
-_MaybeSequence = Union[T, Sequence[T]]
+_MaybeTuple = Union[T, Tuple[T]]
 _Predicate = Callable[[T], bool]
 _WaitGenerator = Callable[..., Generator[float, None, None]]
diff --git a/tests/test_typing.py b/tests/test_typing.py
index 7f53459..8a657c2 100644
--- a/tests/test_typing.py
+++ b/tests/test_typing.py
@@ -32,3 +32,17 @@ def bar():
 )
 def baz():
     pass
+
+
+# Type Successes
+for exception in OSError, tuple([OSError]), (OSError, ValueError):
+    backoff.on_exception(backoff.expo, exception)
+
+
+# Type Failures
+for exception in OSError(), [OSError], (OSError, ValueError()), "hi", (2, 3):
+    try:
+        backoff.on_exception(backoff.expo, exception)
+        raise AssertionError(f"Expected TypeError for {exception}")
+    except TypeError:
+        pass
\ No newline at end of file

From 9d71e8b0ae2a991a4ebff4125f0d077bdb7360ef Mon Sep 17 00:00:00 2001
From: David Slater <davidslater@users.noreply.github.com>
Date: Thu, 9 Feb 2023 15:42:59 -0800
Subject: [PATCH 2/4] add newline

---
 tests/test_typing.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/test_typing.py b/tests/test_typing.py
index 8a657c2..2a58722 100644
--- a/tests/test_typing.py
+++ b/tests/test_typing.py
@@ -45,4 +45,4 @@ def baz():
         backoff.on_exception(backoff.expo, exception)
         raise AssertionError(f"Expected TypeError for {exception}")
     except TypeError:
-        pass
\ No newline at end of file
+        pass

From 9ed616abea5ddb1736a85681e9a4832e0c669972 Mon Sep 17 00:00:00 2001
From: David Slater <davidslater@users.noreply.github.com>
Date: Thu, 9 Feb 2023 15:43:58 -0800
Subject: [PATCH 3/4] sequence not used

---
 backoff/_typing.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/backoff/_typing.py b/backoff/_typing.py
index cc9e6f5..66492b8 100644
--- a/backoff/_typing.py
+++ b/backoff/_typing.py
@@ -1,7 +1,7 @@
 # coding:utf-8
 import logging
 import sys
-from typing import (Any, Callable, Coroutine, Dict, Generator, Sequence, Tuple,
+from typing import (Any, Callable, Coroutine, Dict, Generator, Tuple,
                     TypeVar, Union)
 
 if sys.version_info >= (3, 8):  # pragma: no cover

From e68d3f9971d0ce2f5d949d66932fbe48b1fec420 Mon Sep 17 00:00:00 2001
From: David Slater <davidslater@users.noreply.github.com>
Date: Thu, 2 May 2024 14:50:06 -0700
Subject: [PATCH 4/4] Update backoff/_typing.py

Add ellipsis for 2 more exceptions.
---
 backoff/_typing.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/backoff/_typing.py b/backoff/_typing.py
index 66492b8..cce37d1 100644
--- a/backoff/_typing.py
+++ b/backoff/_typing.py
@@ -39,6 +39,6 @@ class Details(_Details, total=False):
 _Jitterer = Callable[[float], float]
 _MaybeCallable = Union[T, Callable[[], T]]
 _MaybeLogger = Union[str, logging.Logger, None]
-_MaybeTuple = Union[T, Tuple[T]]
+_MaybeTuple = Union[T, Tuple[T, ...]]
 _Predicate = Callable[[T], bool]
 _WaitGenerator = Callable[..., Generator[float, None, None]]