Add warning about changed behavior when passing Sequence for random_seed

Author: ricardoV94

pymc/sampling/mcmc.py

@@ -528,10 +528,8 @@ def sample(
     random_seed : int, array-like of int, or Generator, optional
         Random seed(s) used by the sampling steps. Each step will create its own
         :py:class:`~numpy.random.Generator` object to make its random draws in a way that is
-        indepedent from all other steppers and all other chains. If a list, tuple or array of ints
-        is passed, each entry will be used to seed the creation of ``Generator`` objects.
-        A ``ValueError`` will be raised if the length does not match the number of chains.
-        A ``TypeError`` will be raised if a :py:class:`~numpy.random.RandomState` object is passed.
+        indepedent from all other steppers and all other chains.
+        A ``TypeError`` will be raised if a legacy :py:class:`~numpy.random.RandomState` object is passed.
         We no longer support ``RandomState`` objects because their seeding mechanism does not allow
         easy spawning of new independent random streams that are needed by the step methods.
     progressbar : bool, optional default=True
@@ -730,6 +728,12 @@ def joined_blas_limiter():
 
     if random_seed == -1:
         random_seed = None
+    elif isinstance(random_seed, tuple | list):
+        warnings.warn(
+            "A list or tuple of random_seed no longer specifies the specific random_seed of each chain. "
+            "Use a single seed instead.",
+            UserWarning,
+        )
     rngs = get_random_generator(random_seed).spawn(chains)
     random_seed_list = [rng.integers(2**30) for rng in rngs]