[mypyc] Raise ImportError instead of AttributeError when from-import …

…fails (#10641)

Fixes mypyc/mypyc#707.

mypyc/irbuild/builder.py

@@ -288,20 +288,20 @@ def add_to_non_ext_dict(self, non_ext: NonExtClassInfo,
  key_unicode = self.load_str(key)
  self.call_c(dict_set_item_op, [non_ext.dict, key_unicode, val], line)
 
- def gen_import_from(self, id: str, line: int, imported: List[str]) -> None:
+ def gen_import_from(self, id: str, globals_dict: Value,
+ imported: List[str], line: int) -> Value:
  self.imports[id] = None
 
- globals_dict = self.load_globals_dict()
- null = Integer(0, dict_rprimitive, line)
+ null_dict = Integer(0, dict_rprimitive, line)
  names_to_import = self.new_list_op([self.load_str(name) for name in imported], line)
-
- level = Integer(0, c_int_rprimitive, line)
+ zero_int = Integer(0, c_int_rprimitive, line)
  value = self.call_c(
  import_extra_args_op,
- [self.load_str(id), globals_dict, null, names_to_import, level],
+ [self.load_str(id), globals_dict, null_dict, names_to_import, zero_int],
  line,
  )
  self.add(InitStatic(value, id, namespace=NAMESPACE_MODULE))
+ return value
 
  def gen_import(self, id: str, line: int) -> None:
  self.imports[id] = None

mypyc/irbuild/statement.py

@@ -22,7 +22,7 @@
 )
 from mypyc.ir.rtypes import RInstance, exc_rtuple
 from mypyc.primitives.generic_ops import py_delattr_op
-from mypyc.primitives.misc_ops import type_op
+from mypyc.primitives.misc_ops import type_op, import_from_op
 from mypyc.primitives.exc_ops import (
  raise_exception_op, reraise_exception_op, error_catch_op, exc_matches_op, restore_exc_info_op,
  get_exc_value_op, keep_propagating_op, get_exc_info_op
@@ -172,18 +172,20 @@ def transform_import_from(builder: IRBuilder, node: ImportFrom) -> None:
 
  id = importlib.util.resolve_name('.' * node.relative + node.id, module_package)
 
- imported = [name for name, _ in node.names]
- builder.gen_import_from(id, node.line, imported)
- module = builder.load_module(id)
+ globals = builder.load_globals_dict()
+ imported_names = [name for name, _ in node.names]
+ module = builder.gen_import_from(id, globals, imported_names, node.line)
 
  # Copy everything into our module's dict.
  # Note that we miscompile import from inside of functions here,
  # since that case *shouldn't* load it into the globals dict.
  # This probably doesn't matter much and the code runs basically right.
- globals = builder.load_globals_dict()
  for name, maybe_as_name in node.names:
  as_name = maybe_as_name or name
- obj = builder.py_get_attr(module, name, node.line)
+ obj = builder.call_c(import_from_op,
+ [module, builder.load_str(id),
+ builder.load_str(name), builder.load_str(as_name)],
+ node.line)
  builder.gen_method_call(
  globals, '__setitem__', [builder.load_str(as_name), obj],
  result_type=None, line=node.line)

mypyc/lib-rt/CPy.h

@@ -542,6 +542,9 @@ int CPyStatics_Initialize(PyObject **statics,
  const int *tuples);
 PyObject *CPy_Super(PyObject *builtins, PyObject *self);
 
+PyObject *CPyImport_ImportFrom(PyObject *module, PyObject *package_name,
+ PyObject *import_name, PyObject *as_name);
+
 #ifdef __cplusplus
 }
 #endif

mypyc/lib-rt/misc_ops.c

@@ -643,3 +643,36 @@ CPy_Super(PyObject *builtins, PyObject *self) {
  Py_DECREF(super_type);
  return result;
 }
+
+// This helper function is a simplification of cpython/ceval.c/import_from()
+PyObject *CPyImport_ImportFrom(PyObject *module, PyObject *package_name,
+ PyObject *import_name, PyObject *as_name) {
+ // check if the imported module has an attribute by that name
+ PyObject *x = PyObject_GetAttr(module, import_name);
+ if (x == NULL) {
+ // if not, attempt to import a submodule with that name
+ PyObject *fullmodname = PyUnicode_FromFormat("%U.%U", package_name, import_name);
+ if (fullmodname == NULL) {
+ goto fail;
+ }
+
+ // The following code is a simplification of cpython/import.c/PyImport_GetModule()
+ x = PyObject_GetItem(module, fullmodname);
+ Py_DECREF(fullmodname);
+ if (x == NULL) {
+ goto fail;
+ }
+ }
+ return x;
+
+fail:
+ PyErr_Clear();
+ PyObject *package_path = PyModule_GetFilenameObject(module);
+ PyObject *errmsg = PyUnicode_FromFormat("cannot import name %R from %R (%S)",
+ import_name, package_name, package_path);
+ // NULL checks for errmsg and package_name done by PyErr_SetImportError.
+ PyErr_SetImportError(errmsg, package_name, package_path);
+ Py_DECREF(package_path);
+ Py_DECREF(errmsg);
+ return NULL;
+}

mypyc/primitives/misc_ops.py

@@ -123,6 +123,15 @@
  error_kind=ERR_MAGIC
 )
 
+# Import-from helper op
+import_from_op = custom_op(
+ arg_types=[object_rprimitive, str_rprimitive,
+ str_rprimitive, str_rprimitive],
+ return_type=object_rprimitive,
+ c_function_name='CPyImport_ImportFrom',
+ error_kind=ERR_MAGIC
+)
+
 # Get the sys.modules dictionary
 get_module_dict_op = custom_op(
  arg_types=[],

mypyc/test-data/fixtures/ir.py

@@ -229,6 +229,8 @@ class ValueError(Exception): pass
 
 class AttributeError(Exception): pass
 
+class ImportError(Exception): pass
+
 class NameError(Exception): pass
 
 class LookupError(Exception): pass