[Dy2stat] Add Test and Example Code for Different Access to ProgramTr…

…anslator and Fix Related Bug (PaddlePaddle#23958)

To prepare for publishing APIs, I added tests for that we can access dy2stat through:

@fluid.dygraph.declarative
@fluid.dygraph.jit.declarative
fluid.dygraph.ProgramTranslator()
fluid.dygraph.dygraph_to_static.ProgramTranslator()
fluid.dygraph.dygraph_to_static.program_translator.ProgramTranslator()

It surprised me that we had bugs on those different usages. I have fixed them.

I also added example codes for these new APIs

This PR also pulls my current PR PaddlePaddle#23880, so the PR history is long. For reviewer information, you could review this PR after PaddlePaddle#23880 is merged

python/paddle/fluid/dygraph/__init__.py

@@ -47,6 +47,9 @@
 from . import static_runner
 from .static_runner import StaticModelRunner
 
+from . import dygraph_to_static
+from .dygraph_to_static import ProgramTranslator
+
 __all__ = []
 __all__ += layers.__all__
 __all__ += base.__all__
@@ -57,3 +60,4 @@
 __all__ += learning_rate_scheduler.__all__
 __all__ += backward_strategy.__all__
 __all__ += jit.__all__
+__all__ += ['ProgramTranslator']

python/paddle/fluid/dygraph/dygraph_to_static/ast_transformer.py

@@ -37,9 +37,10 @@
 from paddle.fluid.dygraph.dygraph_to_static.static_analysis import NodeVarType
 from paddle.fluid.dygraph.dygraph_to_static.static_analysis import StaticAnalysisVisitor
 from paddle.fluid.dygraph.dygraph_to_static.utils import ast_to_func
+from paddle.fluid.dygraph.dygraph_to_static.utils import dygraph_class_to_static_api
+from paddle.fluid.dygraph.dygraph_to_static.utils import get_attribute_full_name
 from paddle.fluid.dygraph.dygraph_to_static.utils import is_paddle_api, is_dygraph_api, is_to_variable
 from paddle.fluid.dygraph.dygraph_to_static.utils import to_assign_node, to_static_ast, update_args_of_func
-from paddle.fluid.dygraph.dygraph_to_static.utils import dygraph_class_to_static_api
 
 __all__ = ['DygraphToStaticAst', 'convert_to_static']
 
@@ -96,9 +97,24 @@ def visit_FunctionDef(self, node):
         self.generic_visit(node)
         # Remove the decorated name of dygraph_to_static
         if hasattr(node, 'decorator_list'):
-            decorator_list = [
-                d for d in node.decorator_list if d.id not in DECORATOR_NAMES
-            ]
+            decorator_list = []
+            for d in node.decorator_list:
+                if isinstance(d, gast.Name) and d.id not in DECORATOR_NAMES:
+                    raise NotImplementedError(
+                        "ProgramTranslator hasn't implemented multiple decorators. Please remove "
+                        + d.id + " in " + self.decorate_func_name)
+                if isinstance(d, gast.Attribute):
+                    full_attribute_name = get_attribute_full_name(d)
+                    has_translate_decorator = False
+                    for deco in DECORATOR_NAMES:
+                        if deco in full_attribute_name:
+                            has_translate_decorator = True
+                            break
+                    if not has_translate_decorator:
+                        raise NotImplementedError(
+                            "ProgramTranslator hasn't implemented multiple decorators. Please remove "
+                            + full_attribute_name + " in " +
+                            self.decorate_func_name)
             node.decorator_list = decorator_list
         return node