Refactoring of GatherImportsVisitor

libcst/codemod/visitors/_add_imports.py

@@ -10,32 +10,20 @@
 from libcst import matchers as m, parse_statement
 from libcst._nodes.statement import Import, ImportFrom, SimpleStatementLine
 from libcst.codemod._context import CodemodContext
-from libcst.codemod._visitor import ContextAwareTransformer, ContextAwareVisitor
+from libcst.codemod._visitor import ContextAwareTransformer
+from libcst.codemod.visitors._gather_imports import GatherImportsVisitor
 from libcst.codemod.visitors._imports import ImportItem
 from libcst.helpers import get_absolute_module_from_package_for_import
 from libcst.helpers.common import ensure_type
 
 
-class _GatherTopImportsBeforeStatements(ContextAwareVisitor):
+class _GatherTopImportsBeforeStatements(GatherImportsVisitor):
  """
  Works similarly to GatherImportsVisitor, but only considers imports
  declared before any other statements of the module with the exception
  of docstrings and __strict__ flag.
  """
 
- def __init__(self, context: CodemodContext) -> None:
- super().__init__(context)
- # Track the available imports in this transform
- self.module_imports: Set[str] = set()
- self.object_mapping: Dict[str, Set[str]] = {}
- # Track the aliased imports in this transform
- self.module_aliases: Dict[str, str] = {}
- self.alias_mapping: Dict[str, List[Tuple[str, str]]] = {}
- # Track all of the imports found in this transform
- self.all_imports: Set[Union[libcst.Import, libcst.ImportFrom]] = set()
- # Track the import for every symbol introduced into the module
- self.symbol_mapping: Dict[str, ImportItem] = {}
-
  def leave_Module(self, original_node: libcst.Module) -> None:
  start = 1 if _skip_first(original_node) else 0
  for stmt in original_node.body[start:]:
@@ -45,75 +33,22 @@ def leave_Module(self, original_node: libcst.Module) -> None:
  ):
  stmt = ensure_type(stmt, SimpleStatementLine)
  imp = ensure_type(stmt.body[0], Union[ImportFrom, Import])
- self.all_imports.add(imp)
+ self.all_imports.append(imp)
  else:
  break
  for imp in self.all_imports:
  if m.matches(imp, m.Import()):
  imp = ensure_type(imp, Import)
- self.handle_Import(imp)
+ self._handle_Import(imp)
  else:
  imp = ensure_type(imp, ImportFrom)
- self.handle_ImportFrom(imp)
-
- def handle_Import(self, node: libcst.Import) -> None:
- for name in node.names:
- alias = name.evaluated_alias
- imp = ImportItem(name.evaluated_name, alias=alias)
- if alias is not None:
- # Track this as an aliased module
- self.module_aliases[name.evaluated_name] = alias
- self.symbol_mapping[alias] = imp
- else:
- # Get the module we're importing as a string.
- self.module_imports.add(name.evaluated_name)
- self.symbol_mapping[name.evaluated_name] = imp
+ self._handle_ImportFrom(imp)
 
- def handle_ImportFrom(self, node: libcst.ImportFrom) -> None:
- # Get the module we're importing as a string.
- module = get_absolute_module_from_package_for_import(
- self.context.full_package_name, node
- )
- if module is None:
- # Can't get the absolute import from relative, so we can't
- # support this.
- return
- nodenames = node.names
- if isinstance(nodenames, libcst.ImportStar):
- # We cover everything, no need to bother tracking other things
- self.object_mapping[module] = set("*")
- return
- elif isinstance(nodenames, Sequence):
- # Get the list of imports we're aliasing in this import
- new_aliases = [
- (ia.evaluated_name, ia.evaluated_alias)
- for ia in nodenames
- if ia.asname is not None
- ]
- if new_aliases:
- if module not in self.alias_mapping:
- self.alias_mapping[module] = []
- # pyre-ignore We know that aliases are not None here.
- self.alias_mapping[module].extend(new_aliases)
-
- # Get the list of imports we're importing in this import
- new_objects = {ia.evaluated_name for ia in nodenames if ia.asname is None}
- if new_objects:
- if module not in self.object_mapping:
- self.object_mapping[module] = set()
-
- # Make sure that we don't add to a '*' module
- if "*" in self.object_mapping[module]:
- self.object_mapping[module] = set("*")
- return
-
- self.object_mapping[module].update(new_objects)
- for ia in nodenames:
- imp = ImportItem(
- module, obj_name=ia.evaluated_name, alias=ia.evaluated_alias
- )
- key = ia.evaluated_alias or ia.evaluated_name
- self.symbol_mapping[key] = imp
+ def visit_ImportFrom(self, node: libcst.ImportFrom) -> None:
+ pass
+
+ def visit_Import(self, node: libcst.Import) -> None:
+ pass
 
 
 class AddImportsVisitor(ContextAwareTransformer):
@@ -277,7 +212,7 @@ def visit_Module(self, node: libcst.Module) -> None:
  # Do a preliminary pass to gather the imports we already have at the top
  gatherer = _GatherTopImportsBeforeStatements(self.context)
  node.visit(gatherer)
- self.all_imports = gatherer.all_imports
+ self.all_imports = set(gatherer.all_imports)
 
  self.module_imports = self.module_imports - gatherer.module_imports
  for module, alias in gatherer.module_aliases.items():

libcst/codemod/visitors/_gather_imports.py

@@ -67,7 +67,9 @@ def __init__(self, context: CodemodContext) -> None:
  def visit_Import(self, node: libcst.Import) -> None:
  # Track this import statement for later analysis.
  self.all_imports.append(node)
+ self._handle_Import(node)
 
+ def _handle_Import(self, node: libcst.Import) -> None:
  for name in node.names:
  alias = name.evaluated_alias
  imp = ImportItem(name.evaluated_name, alias=alias)
@@ -83,7 +85,9 @@ def visit_Import(self, node: libcst.Import) -> None:
  def visit_ImportFrom(self, node: libcst.ImportFrom) -> None:
  # Track this import statement for later analysis.
  self.all_imports.append(node)
+ self._handle_ImportFrom(node)
 
+ def _handle_ImportFrom(self, node: libcst.ImportFrom) -> None:
  # Get the module we're importing as a string.
  module = get_absolute_module_from_package_for_import(
  self.context.full_package_name, node