[Cherry-pick] remove distributed prepare context (#30219) (#30256)

att, cherry-pick of #30219

python/paddle/distributed/__init__.py

@@ -19,7 +19,6 @@ from . import parallel
 from .parallel import init_parallel_env
 from .parallel import get_rank
 from .parallel import get_world_size
-from paddle.fluid.dygraph.parallel import prepare_context  #DEFINE_ALIAS
 from paddle.fluid.dygraph.parallel import ParallelEnv  #DEFINE_ALIAS
 from paddle.distributed.fleet.dataset import *
 
@@ -34,7 +33,6 @@ __all__ += [
     "init_parallel_env",
     "get_rank",
     "get_world_size",
-    "prepare_context",
     "ParallelEnv",
     "InMemoryDataset",
     "QueueDataset",

python/paddle/fluid/tests/unittests/test_directory_migration.py

@@ -38,8 +38,7 @@ class TestDirectory(unittest.TestCase):
             'paddle.enable_static', 'paddle.disable_static',
             'paddle.in_dynamic_mode', 'paddle.to_tensor', 'paddle.grad',
             'paddle.no_grad', 'paddle.static.save', 'paddle.static.load',
-            'paddle.distributed.ParallelEnv',
-            'paddle.distributed.prepare_context', 'paddle.DataParallel',
+            'paddle.distributed.ParallelEnv', 'paddle.DataParallel',
             'paddle.jit', 'paddle.jit.TracedLayer', 'paddle.jit.to_static',
             'paddle.jit.ProgramTranslator', 'paddle.jit.TranslatedLayer',
             'paddle.jit.save', 'paddle.jit.load',

python/paddle/fluid/tests/unittests/test_imperative_data_parallel.py

@@ -43,7 +43,7 @@ class MLP(fluid.Layer):
 class TestDataParallelStateDict(unittest.TestCase):
     def test_data_parallel_state_dict(self):
         with fluid.dygraph.guard():
-            strategy = paddle.distributed.prepare_context()
+            strategy = dygraph.parallel.prepare_context()
             mlp = MLP()
             parallel_mlp = dygraph.parallel.DataParallel(mlp, strategy)