Make plugin type check more flexible (Fabric) (#20452)

* make plugin type check more flexible

* Change signature and make the equivalent changes to Fabric connector

---------

Co-authored-by: Jianing Yang <[email protected]>
Co-authored-by: Jirka Borovec <[email protected]>

Author: 3 people

src/lightning/fabric/connector.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 import os
 from collections import Counter
+from collections.abc import Iterable
 from typing import Any, Optional, Union, cast
 
 import torch
@@ -102,7 +103,7 @@ def __init__(
         devices: Union[list[int], str, int] = "auto",
         num_nodes: int = 1,
         precision: Optional[_PRECISION_INPUT] = None,
-        plugins: Optional[Union[_PLUGIN_INPUT, list[_PLUGIN_INPUT]]] = None,
+        plugins: Optional[Union[_PLUGIN_INPUT, Iterable[_PLUGIN_INPUT]]] = None,
     ) -> None:
         # These arguments can be set through environment variables set by the CLI
         accelerator = self._argument_from_env("accelerator", accelerator, default="auto")
@@ -165,7 +166,7 @@ def _check_config_and_set_final_flags(
         strategy: Union[str, Strategy],
         accelerator: Union[str, Accelerator],
         precision: Optional[_PRECISION_INPUT],
-        plugins: Optional[Union[_PLUGIN_INPUT, list[_PLUGIN_INPUT]]],
+        plugins: Optional[Union[_PLUGIN_INPUT, Iterable[_PLUGIN_INPUT]]],
     ) -> None:
         """This method checks:
 
@@ -180,7 +181,7 @@ def _check_config_and_set_final_flags(
 
         """
         if plugins is not None:
-            plugins = [plugins] if not isinstance(plugins, list) else plugins
+            plugins = [plugins] if not isinstance(plugins, Iterable) else plugins
 
         if isinstance(strategy, str):
             strategy = strategy.lower()

src/lightning/pytorch/trainer/connectors/accelerator_connector.py

@@ -79,7 +79,7 @@ def __init__(
         num_nodes: int = 1,
         accelerator: Union[str, Accelerator] = "auto",
         strategy: Union[str, Strategy] = "auto",
-        plugins: Optional[Union[_PLUGIN_INPUT, list[_PLUGIN_INPUT]]] = None,
+        plugins: Optional[Union[_PLUGIN_INPUT, Iterable[_PLUGIN_INPUT]]] = None,
         precision: Optional[_PRECISION_INPUT] = None,
         sync_batchnorm: bool = False,
         benchmark: Optional[bool] = None,
@@ -167,7 +167,7 @@ def _check_config_and_set_final_flags(
         strategy: Union[str, Strategy],
         accelerator: Union[str, Accelerator],
         precision: Optional[_PRECISION_INPUT],
-        plugins: Optional[Union[_PLUGIN_INPUT, list[_PLUGIN_INPUT]]],
+        plugins: Optional[Union[_PLUGIN_INPUT, Iterable[_PLUGIN_INPUT]]],
         sync_batchnorm: bool,
     ) -> None:
         """This method checks: