fix: update handling of invalid seeds via PL_GLOBAL_SEED

Author: jonathanking

src/lightning/fabric/utilities/seed.py

@@ -28,7 +28,7 @@ def seed_everything(seed: Optional[int] = None, workers: bool = False, verbose:
         seed: the integer value seed for global random state in Lightning.
             If ``None``, it will read the seed from ``PL_GLOBAL_SEED`` env variable. If ``None`` and the
             ``PL_GLOBAL_SEED`` env variable is not set, then the seed defaults to 0. If the seed is provided
-            as an integer but is not in bounds, a ValueError is raised.
+            but is not in bounds or cannot be casted to int, a ValueError is raised.
         workers: if set to ``True``, will properly configure all dataloaders passed to the
             Trainer with a ``worker_init_fn``. If the user already provides such a function
             for their dataloaders, setting this argument will have no influence. See also:
@@ -45,8 +45,7 @@ def seed_everything(seed: Optional[int] = None, workers: bool = False, verbose:
             try:
                 seed = int(env_seed)
             except ValueError:
-                seed = 0
-                rank_zero_warn(f"Invalid seed found: {repr(env_seed)}, seed set to {seed}")
+                raise ValueError(f"Invalid seed specified via PL_GLOBAL_SEED: {repr(env_seed)}")
     elif not isinstance(seed, int):
         seed = int(seed)