chore: Check types with ty and update some type annotations

CHANGELOG.md

@@ -20,6 +20,8 @@
 
 - Apply the Ruff `FA` rules [#104](https://github.com/python-backoff/backoff/pull/104) (from [@edgarrmondragon](https://github.com/edgarrmondragon))
 
+- Check types with [`ty`](https://docs.astral.sh/ty/) and update some type annotations [#179](https://github.com/python-backoff/backoff/pull/179)
+
 ## [v2.3.1] - 2025-12-18
 
 ### Fixed

backoff/_common.py

@@ -70,7 +70,7 @@ def _config_handlers(
         assert log_level is not None, "Log level is not specified"
         # bind the specified logger to the default log handler
         log_handler = functools.partial(
-            default_handler,
+            default_handler,  # ty:ignore[invalid-argument-type]
             logger=logger,
             log_level=log_level,
         )

backoff/_typing.py

@@ -40,5 +40,5 @@ class Details(_Details, total=False):
 _MaybeCallable = Union[T, Callable[[], T]]
 _MaybeLogger = Union[str, logging.Logger, logging.LoggerAdapter, None]
 _MaybeSequence = Union[T, Sequence[T]]
-_Predicate = Callable[[T], bool]
-_WaitGenerator = Callable[..., Generator[float, None, None]]
+_Predicate = Union[Callable[[T], bool], Callable[[T], Coroutine[T, None, bool]]]
+_WaitGenerator = Callable[..., Generator[Union[float, None], None, None]]

backoff/_wait_gen.py

@@ -12,7 +12,7 @@ def expo(
     base: float = 2,
     factor: float = 1,
     max_value: float | None = None,
-) -> Generator[float, Any, None]:
+) -> Generator[float | None, Any, None]:
     """Generator for exponential decay.
 
     Args:
@@ -38,7 +38,7 @@ def decay(
     initial_value: float = 1,
     decay_factor: float = 1,
     min_value: float | None = None,
-) -> Generator[float, Any, None]:
+) -> Generator[float | None, Any, None]:
     """Generator for exponential decay[1]:
 
     Args:
@@ -62,7 +62,7 @@ def decay(
             yield min_value
 
 
-def fibo(max_value: int | None = None) -> Generator[int, None, None]:
+def fibo(max_value: int | None = None) -> Generator[int | None, None, None]:
     """Generator for fibonaccial decay.
 
     Args:
@@ -85,7 +85,7 @@ def fibo(max_value: int | None = None) -> Generator[int, None, None]:
 
 def constant(
     interval: int | Iterable[float] = 1,
-) -> Generator[float, None, None]:
+) -> Generator[int | float | None, None, None]:
     """Generator for constant intervals.
 
     Args:
@@ -97,16 +97,16 @@ def constant(
     try:
         itr = iter(interval)  # type: ignore
     except TypeError:
-        itr = itertools.repeat(interval)  # type: ignore
+        itr = itertools.repeat(interval)  # type: ignore[arg-type]
 
     for val in itr:
-        yield val
+        yield val  # ty:ignore[invalid-yield]
 
 
 def runtime(
     *,
     value: Callable[[Any], float],
-) -> Generator[float, None, None]:
+) -> Generator[float | None, None, None]:
     """Generator that is based on parsing the return value or thrown
         exception of the decorated method
 

pyproject.toml

@@ -62,6 +62,7 @@ test = [
 typing = [
     { include-group = "test" },
     "mypy>=0.942",
+    "ty>=0.0.59",
     "types-requests>=2.27.20",
 ]
 
@@ -134,6 +135,15 @@ commands = [
       "tests",
     ], extend = true },
   ],
+  [
+    "ty",
+    "check",
+    { replace = "if", condition = "env.GITHUB_ACTIONS == 'true'", then = [ "--output-format=github" ], else = [], extend = true },
+    { replace = "posargs", default = [
+      "backoff",
+      "tests",
+    ], extend = true },
+  ],
 ]
 
 [tool.tox.env.docs]

tests/test_backoff.py

@@ -1,5 +1,4 @@
 import logging
-import random
 import re
 import sys
 import threading
@@ -531,7 +530,6 @@ def emptiness(*args, **kwargs):
 # on_predicate should support 0-argument jitter function.
 def test_on_exception_success_0_arg_jitter(monkeypatch):
     monkeypatch.setattr("time.sleep", lambda x: None)
-    monkeypatch.setattr("random.random", lambda: 0)
 
     backoffs, giveups, successes = [], [], []
 
@@ -541,7 +539,7 @@ def test_on_exception_success_0_arg_jitter(monkeypatch):
         on_success=successes.append,
         on_backoff=backoffs.append,
         on_giveup=giveups.append,
-        jitter=random.random,
+        jitter=lambda: 0.0,  # ty:ignore[invalid-argument-type]
         interval=0,
     )
     @_save_target
@@ -550,7 +548,9 @@ def succeeder(*args, **kwargs):
         if len(backoffs) < 2:
             raise ValueError("catch me")
 
-    with pytest.deprecated_call():
+    with pytest.deprecated_call(
+        match="Nullary jitter function signature is deprecated",
+    ):
         succeeder(1, 2, 3, foo=1, bar=2)
 
     # we try 3 times, backing off twice before succeeding
@@ -587,7 +587,6 @@ def succeeder(*args, **kwargs):
 # on_predicate should support 0-argument jitter function.
 def test_on_predicate_success_0_arg_jitter(monkeypatch):
     monkeypatch.setattr("time.sleep", lambda x: None)
-    monkeypatch.setattr("random.random", lambda: 0)
 
     backoffs, giveups, successes = [], [], []
 
@@ -596,15 +595,17 @@ def test_on_predicate_success_0_arg_jitter(monkeypatch):
         on_success=successes.append,
         on_backoff=backoffs.append,
         on_giveup=giveups.append,
-        jitter=random.random,
+        jitter=lambda: 0.0,  # ty:ignore[invalid-argument-type]
         interval=0,
     )
     @_save_target
     def success(*args, **kwargs):
         # succeed after we've backed off twice
         return len(backoffs) == 2
 
-    with pytest.deprecated_call():
+    with pytest.deprecated_call(
+        match="Nullary jitter function signature is deprecated",
+    ):
         success(1, 2, 3, foo=1, bar=2)
 
     # we try 3 times, backing off twice before succeeding

tests/test_backoff_async.py

@@ -1,5 +1,4 @@
 import asyncio  # Python 3.5 code and syntax is allowed in this file
-import random
 
 import pytest
 
@@ -347,7 +346,7 @@ async def foo_bar_baz():
 async def test_on_exception_giveup_coro(monkeypatch):
     monkeypatch.setattr("asyncio.sleep", _await_none)
 
-    async def on_baz(e):
+    async def on_baz(e: Exception) -> bool:
         return str(e) == "baz"
 
     vals = ["baz", "bar", "foo"]
@@ -518,7 +517,6 @@ async def falsey():
 @pytest.mark.asyncio
 async def test_on_exception_success_0_arg_jitter(monkeypatch):
     monkeypatch.setattr("asyncio.sleep", _await_none)
-    monkeypatch.setattr("random.random", lambda: 0)
 
     log, log_success, log_backoff, log_giveup = _log_hdlrs()
 
@@ -528,7 +526,7 @@ async def test_on_exception_success_0_arg_jitter(monkeypatch):
         on_success=log_success,
         on_backoff=log_backoff,
         on_giveup=log_giveup,
-        jitter=random.random,
+        jitter=lambda: 0.0,  # ty:ignore[invalid-argument-type]
         interval=0,
     )
     @_save_target
@@ -537,7 +535,9 @@ async def succeeder(*args, **kwargs):
         if len(log["backoff"]) < 2:
             raise ValueError("catch me")
 
-    with pytest.deprecated_call():
+    with pytest.deprecated_call(
+        match="Nullary jitter function signature is deprecated",
+    ):
         await succeeder(1, 2, 3, foo=1, bar=2)
 
     # we try 3 times, backing off twice before succeeding
@@ -575,7 +575,6 @@ async def succeeder(*args, **kwargs):
 @pytest.mark.asyncio
 async def test_on_predicate_success_0_arg_jitter(monkeypatch):
     monkeypatch.setattr("asyncio.sleep", _await_none)
-    monkeypatch.setattr("random.random", lambda: 0)
 
     log, log_success, log_backoff, log_giveup = _log_hdlrs()
 
@@ -584,15 +583,17 @@ async def test_on_predicate_success_0_arg_jitter(monkeypatch):
         on_success=log_success,
         on_backoff=log_backoff,
         on_giveup=log_giveup,
-        jitter=random.random,
+        jitter=lambda: 0.0,  # ty:ignore[invalid-argument-type]
         interval=0,
     )
     @_save_target
     async def success(*args, **kwargs):
         # succeed after we've backed off twice
         return len(log["backoff"]) == 2
 
-    with pytest.deprecated_call():
+    with pytest.deprecated_call(
+        match="Nullary jitter function signature is deprecated",
+    ):
         await success(1, 2, 3, foo=1, bar=2)
 
     # we try 3 times, backing off twice before succeeding

tests/test_wait_gen.py

@@ -102,4 +102,4 @@ def test_runtime():
     gen = backoff.runtime(value=lambda x: x)
     gen.send(None)
     for i in range(20):
-        assert i == gen.send(i)
+        assert i == gen.send(i)  # ty:ignore[invalid-argument-type]