made drop_method into drop, with support for classes

.cross_sync/README.md

@@ -51,8 +51,8 @@ CrossSync provides a set of annotations to mark up async classes, to guide the g
   - if add_mapping is included, the async and sync classes can be accessed using a shared CrossSync.X alias
 - `@CrossSync.convert`
   - marks async functions for conversion. Unmarked methods will be copied as-is
-- `@CrossSync.drop_method`
-  - marks functions that should not be included in sync output
+- `@CrossSync.drop`
+  - marks functions or classes that should not be included in sync output
 - `@CrossSync.pytest`
   - marks test functions. Test functions automatically have all async keywords stripped (i.e., rm_aio is unneeded)
 - `CrossSync.add_mapping`

.cross_sync/transformers.py

@@ -240,18 +240,16 @@ def visit_ClassDef(self, node):
         Called for each class in file. If class has a CrossSync decorator, it will be transformed
         according to the decorator arguments. Otherwise, class is returned unchanged
         """
-        for decorator in node.decorator_list:
+        orig_decorators = node.decorator_list
+        for decorator in orig_decorators:
             try:
                 handler = AstDecorator.get_for_node(decorator)
-                if isinstance(handler, ExportSync):
-                    # transformation is handled in sync_ast_transform method of the decorator
-                    after_export = handler.sync_ast_transform(node, globals())
-                    return self.generic_visit(after_export)
+                # transformation is handled in sync_ast_transform method of the decorator
+                node = handler.sync_ast_transform(node, globals())
             except ValueError:
                 # not cross_sync decorator
                 continue
-        # cross_sync decorator not found. Drop from sync version
-        return None
+        return self.generic_visit(node) if node else None
 
     def visit_If(self, node):
         """

google/cloud/bigtable/data/_sync/cross_sync/_decorators.py

@@ -342,14 +342,14 @@ def sync_ast_transform(self, wrapped_node, transformers_globals):
         return super().sync_ast_transform(converted, transformers_globals)
 
 
-class DropMethod(AstDecorator):
+class Drop(AstDecorator):
     """
-    Method decorator to drop async methods from the sync output
+    Method decorator to drop methods or classes from the sync output
     """
 
     def sync_ast_transform(self, wrapped_node, transformers_globals):
         """
-        Drop method from sync output
+        Drop from sync output
         """
         return None
 

google/cloud/bigtable/data/_sync/cross_sync/cross_sync.py

@@ -62,7 +62,7 @@ async def async_func(self, arg: int) -> int:
 from ._decorators import (
     ExportSync,
     Convert,
-    DropMethod,
+    Drop,
     Pytest,
     PytestFixture,
 )
@@ -99,7 +99,7 @@ class CrossSync(metaclass=MappingMeta):
     # decorators
     export_sync = ExportSync.decorator  # decorate classes to convert
     convert = Convert.decorator  # decorate methods to convert from async to sync
-    drop_method = DropMethod.decorator  # decorate methods to remove from sync version
+    drop = Drop.decorator  # decorate methods to remove from sync version
     pytest = Pytest.decorator  # decorate test methods to run with pytest-asyncio
     pytest_fixture = (
         PytestFixture.decorator

tests/system/cross_sync/test_cases/cross_sync_files.yaml

@@ -87,7 +87,7 @@ tests:
               async with self.base.connection():
                   return await self.base.my_method()
 
-          @CrossSync.drop_method
+          @CrossSync.drop
           async def async_only_method(self):
               await self.async_operation()
 
@@ -120,6 +120,7 @@ tests:
       __CROSS_SYNC_OUTPUT__ = "out.path"
       @CrossSync.export_sync(sync_name="MyClass")
       class MyAsyncClass:
+          @CrossSync.drop
           class NestedAsyncClass:
               async def nested_method(self, base: AsyncBase):
                   pass
@@ -263,14 +264,27 @@ tests:
         def keep_method(self):
             pass
 
-        @CrossSync.drop_method
+        @CrossSync.drop
         async def async_only_method(self):
             await self.async_operation()
     transformers: [CrossSyncFileProcessor]
     after: |
         def keep_method(self):
             pass
 
+  - description: "Drop class from sync version"
+    before: |
+      __CROSS_SYNC_OUTPUT__ = "out.path"
+      @CrossSync.drop
+      class DropMe:
+          pass
+      class Keeper:
+          pass
+    transformers: [CrossSyncFileProcessor]
+    after: |
+      class Keeper:
+          pass
+
   - description: "Convert.pytest"
     before: |
         __CROSS_SYNC_OUTPUT__ = "out.path"

tests/unit/data/_sync/test_cross_sync_decorators.py

@@ -20,7 +20,7 @@
 from google.cloud.bigtable.data._sync.cross_sync._decorators import (
     ExportSync,
     Convert,
-    DropMethod,
+    Drop,
     Pytest,
     PytestFixture,
 )
@@ -412,9 +412,9 @@ def test_sync_ast_transform_add_docstring_format(
         assert result.body[0].value.value == expected
 
 
-class TestDropMethodDecorator:
+class TestDropDecorator:
     def _get_class(self):
-        return DropMethod
+        return Drop
 
     def test_decorator_functionality(self):
         """