fix: call wait_chain members positionally

releasenotes/notes/fix-wait-chain-keyword-state-7c2f5b9e04a1d836.yaml

@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    ``wait_chain`` now passes the retry state positionally, matching how
+    ``wait_combine`` and ``BaseRetrying`` invoke ``wait``. It previously
+    passed it as the keyword ``retry_state=``, which crashed on any callable
+    whose parameter had a different name.

tenacity/wait.py

@@ -123,7 +123,7 @@ def wait_chained():
                   "thereafter.")
     """
 
-    def __init__(self, *strategies: wait_base) -> None:
+    def __init__(self, *strategies: "WaitBaseT") -> None:
         if not strategies:
             raise ValueError("wait_chain() requires at least one strategy")
         self.strategies = strategies
@@ -132,7 +132,9 @@ def __init__(self, *strategies: wait_base) -> None:
     def __call__(self, retry_state: "RetryCallState") -> float:
         wait_func_no = min(max(retry_state.attempt_number, 1), len(self.strategies))
         wait_func = self.strategies[wait_func_no - 1]
-        return wait_func(retry_state=retry_state)
+        # Positional, like `wait_combine`: a `WaitBaseT` callable is only
+        # guaranteed to take the state positionally.
+        return wait_func(retry_state)
 
 
 class wait_exception(wait_base):

tests/test_tenacity.py

@@ -612,6 +612,12 @@ def test_wait_chain_requires_at_least_one_strategy(self) -> None:
         with self.assertRaises(ValueError):
             Retrying(wait=tenacity.wait_chain())
 
+    def test_wait_chain_passes_state_positionally(self) -> None:
+        # A WaitBaseT callable only promises to take the state positionally;
+        # its parameter name is its own business.
+        chained = tenacity.wait_chain(lambda rs: 2.0)
+        self.assertEqual(chained(make_retry_state(1, 5)), 2.0)
+
     def test_wait_random_exponential(self) -> None:
         fn = tenacity.wait_random_exponential(0.5, 60.0)