Remove support for passing strategy name to plugins

CHANGELOG.md

@@ -103,7 +103,10 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Removed deprecated `GPUStatsMonitor` callback ([#12554](https://github.com/PyTorchLightning/pytorch-lightning/pull/12554))
 
 
-- Removed support for passing strategy names or strategy classes to the accelerator Trainer argument ([#12696](https://github.com/PyTorchLightning/pytorch-lightning/pull/12696))
+- Removed support for passing strategy names or strategy instances to the accelerator Trainer argument ([#12696](https://github.com/PyTorchLightning/pytorch-lightning/pull/12696))
+
+
+- Removed support for passing strategy names or strategy instances to the plugins Trainer argument ([#12700](https://github.com/PyTorchLightning/pytorch-lightning/pull/12700))
 
 
 ### Fixed

pytorch_lightning/trainer/connectors/accelerator_connector.py

@@ -123,21 +123,18 @@ def __init__(
 
             C. plugins flag could be:
                 1. List of str, which could contain:
-                    i. strategy str
-                    ii. precision str (Not supported in the old accelerator_connector version)
-                    iii. checkpoint_io str (Not supported in the old accelerator_connector version)
-                    iv. cluster_environment str (Not supported in the old accelerator_connector version)
+                    i. precision str (Not supported in the old accelerator_connector version)
+                    ii. checkpoint_io str (Not supported in the old accelerator_connector version)
+                    iii. cluster_environment str (Not supported in the old accelerator_connector version)
                 2. List of class, which could contains:
-                    i. strategy class (deprecated in 1.5 will be removed in 1.7)
-                    ii. precision class (should be removed, and precision flag should allow user pass classes)
-                    iii. checkpoint_io class
-                    iv. cluster_environment class
+                    i. precision class (should be removed, and precision flag should allow user pass classes)
+                    ii. checkpoint_io class
+                    iii. cluster_environment class
 
 
         priorities which to take when:
             A. Class > str
             B. Strategy > Accelerator/precision/plugins
-            C. TODO When multiple flag set to the same thing
         """
         if benchmark and deterministic:
             rank_zero_warn(
@@ -228,13 +225,14 @@ def _check_config_and_set_final_flags(
     ) -> None:
         """This method checks:
 
-        1. strategy: strategy and plugin can be set to strategies
+        1. strategy: whether the strategy name is valid, and sets the internal flags if it is.
         2. accelerator: if the value of the accelerator argument is a type of accelerator (instance or string),
             set self._accelerator_flag accordingly.
         3. precision: The final value of the precision flag may be determined either by the precision argument or
             by a plugin instance.
-        4. plugins: a plugin could occur as a value of the strategy argument (handled by 1), or the precision
-            argument (handled by 3). We also extract the CheckpointIO and ClusterEnvironment plugins.
+        4. plugins: The list of plugins may contain a Precision plugin, CheckpointIO, ClusterEnvironment and others.
+            Additionally, other flags such as `precision` or `sync_batchnorm` can populate the list with the
+            corresponding plugin instances.
         """
         if plugins is not None:
             plugins = [plugins] if not isinstance(plugins, list) else plugins
@@ -254,18 +252,6 @@ def _check_config_and_set_final_flags(
                     "`Trainer(strategy='tpu_spawn')` is not a valid strategy,"
                     " you can use `Trainer(strategy='ddp_spawn', accelerator='tpu')` instead."
                 )
-            if plugins:
-                for plugin in plugins:
-                    if isinstance(plugin, Strategy):
-                        raise MisconfigurationException(
-                            f"You have passed `Trainer(strategy={strategy})`"
-                            f" and you can only specify one strategy, but you have passed {plugin} as a plugin."
-                        )
-                    if isinstance(plugin, str) and plugin in self._registered_strategies:
-                        raise MisconfigurationException(
-                            f"You have passed `Trainer(strategy={strategy})`"
-                            f" and you can only specify one strategy, but you have passed {plugin} as a plugin."
-                        )
 
         if accelerator is not None:
             if accelerator in self._accelerator_types or accelerator == "auto" or isinstance(accelerator, Accelerator):
@@ -281,15 +267,7 @@ def _check_config_and_set_final_flags(
         if plugins:
             plugins_flags_types: Dict[str, int] = Counter()
             for plugin in plugins:
-                if isinstance(plugin, Strategy) or isinstance(plugin, str) and plugin in self._registered_strategies:
-                    self._strategy_flag = plugin
-                    rank_zero_deprecation(
-                        f"Passing {plugin} `strategy` to the `plugins` flag in Trainer has been deprecated"
-                        f" in v1.5 and will be removed in v1.7. Use `Trainer(strategy={plugin})` instead."
-                    )
-                    plugins_flags_types[Strategy.__name__] += 1
-
-                elif isinstance(plugin, PrecisionPlugin):
+                if isinstance(plugin, PrecisionPlugin):
                     self._precision_plugin_flag = plugin
                     plugins_flags_types[PrecisionPlugin.__name__] += 1
                 elif isinstance(plugin, CheckpointIO):
@@ -309,7 +287,7 @@ def _check_config_and_set_final_flags(
                 else:
                     raise MisconfigurationException(
                         f"Found invalid type for plugin {plugin}. Expected one of: PrecisionPlugin, "
-                        "CheckpointIO, ClusterEnviroment, LayerSync, or Strategy."
+                        "CheckpointIO, ClusterEnviroment, or LayerSync."
                     )
 
             duplicated_plugin_key = [k for k, v in plugins_flags_types.items() if v > 1]

tests/accelerators/test_accelerator_connector.py

@@ -330,12 +330,6 @@ def test_unsupported_strategy_types_on_cpu(strategy):
     assert isinstance(trainer.strategy, DDPStrategy)
 
 
-def test_exception_when_strategy_used_with_plugins():
-    with pytest.raises(MisconfigurationException, match="only specify one strategy, but you have passed"):
-        with pytest.deprecated_call(match=r"`strategy` to the `plugins` flag in Trainer has been deprecated"):
-            Trainer(plugins="ddp_find_unused_parameters_false", strategy="ddp_spawn")
-
-
 def test_exception_invalid_strategy():
     with pytest.raises(MisconfigurationException, match=r"strategy='ddp_cpu'\)` is not a valid"):
         Trainer(strategy="ddp_cpu")

tests/deprecated_api/test_remove_1-7.py

@@ -289,11 +289,6 @@ def test_v1_7_0_deprecate_parameter_validation():
         from pytorch_lightning.core.decorators import parameter_validation  # noqa: F401
 
 
-def test_v1_7_0_passing_strategy_to_plugins_flag():
-    with pytest.deprecated_call(match="has been deprecated in v1.5 and will be removed in v1.7."):
-        Trainer(plugins="ddp_spawn")
-
-
 def test_v1_7_0_weights_summary_trainer(tmpdir):
     with pytest.deprecated_call(match=r"Setting `Trainer\(weights_summary=full\)` is deprecated in v1.5"):
         t = Trainer(weights_summary="full")