Disallow invalid seed string values

CHANGELOG.md

@@ -221,6 +221,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Reset metrics before each task starts ([#9410](https://github.com/PyTorchLightning/pytorch-lightning/pull/9410))
 
 
+- `seed_everything` now fails when an invalid seed value is passed instead of selecting a random seed ([#8787](https://github.com/PyTorchLightning/pytorch-lightning/pull/8787))
+
+
 ### Deprecated
 
 - Deprecated `LightningModule.summarize()` in favor of `pytorch_lightning.utilities.model_summary.summarize()`

pyproject.toml

@@ -82,6 +82,7 @@ module = [
     "pytorch_lightning.utilities.memory",
     "pytorch_lightning.utilities.model_summary",
     "pytorch_lightning.utilities.parsing",
+    "pytorch_lightning.utilities.seed",
     "pytorch_lightning.utilities.xla_device",
 ]
 ignore_errors = "False"

pytorch_lightning/utilities/seed.py

@@ -46,13 +46,19 @@ def seed_everything(seed: Optional[int] = None, workers: bool = False) -> int:
     max_seed_value = np.iinfo(np.uint32).max
     min_seed_value = np.iinfo(np.uint32).min
 
-    try:
-        if seed is None:
-            seed = os.environ.get("PL_GLOBAL_SEED")
+    if seed is None:
+        env_seed = os.environ.get("PL_GLOBAL_SEED")
+        if env_seed is None:
+            seed = _select_seed_randomly(min_seed_value, max_seed_value)
+            rank_zero_warn(f"No seed found, seed set to {seed}")
+        else:
+            try:
+                seed = int(env_seed)
+            except ValueError:
+                seed = _select_seed_randomly(min_seed_value, max_seed_value)
+                rank_zero_warn(f"Invalid seed found: {repr(env_seed)}, seed set to {seed}")
+    elif not isinstance(seed, int):
         seed = int(seed)
-    except (TypeError, ValueError):
-        seed = _select_seed_randomly(min_seed_value, max_seed_value)
-        rank_zero_warn(f"No correct seed found, seed set to {seed}")
 
     if not (min_seed_value <= seed <= max_seed_value):
         rank_zero_warn(f"{seed} is not in bounds, numpy accepts from {min_seed_value} to {max_seed_value}")
@@ -87,7 +93,7 @@ def reset_seed() -> None:
         seed_everything(int(seed), workers=bool(workers))
 
 
-def pl_worker_init_function(worker_id: int, rank: Optional = None) -> None:  # pragma: no cover
+def pl_worker_init_function(worker_id: int, rank: Optional[int] = None) -> None:  # pragma: no cover
     """The worker_init_fn that Lightning automatically adds to your dataloader if you previously set set the seed
     with ``seed_everything(seed, workers=True)``.
 

tests/utilities/test_seed.py

@@ -10,7 +10,7 @@
 @mock.patch.dict(os.environ, {}, clear=True)
 def test_seed_stays_same_with_multiple_seed_everything_calls():
     """Ensure that after the initial seed everything, the seed stays the same for the same run."""
-    with pytest.warns(UserWarning, match="No correct seed found"):
+    with pytest.warns(UserWarning, match="No seed found"):
         seed_utils.seed_everything()
     initial_seed = os.environ.get("PL_GLOBAL_SEED")
 
@@ -32,7 +32,7 @@ def test_correct_seed_with_environment_variable():
 @mock.patch.object(seed_utils, attribute="_select_seed_randomly", new=lambda *_: 123)
 def test_invalid_seed():
     """Ensure that we still fix the seed even if an invalid seed is given."""
-    with pytest.warns(UserWarning, match="No correct seed found"):
+    with pytest.warns(UserWarning, match="Invalid seed found"):
         seed = seed_utils.seed_everything()
     assert seed == 123