wip version of __attrs_init_(). tests pass for py38

src/attr/_make.py

@@ -46,6 +46,10 @@
 # Unique object for unequivocal getattr() defaults.
 _sentinel = object()
 
+# Need a forward definition of Factory because _make_init() refers to
+# it, but since Factory is an attrs class, it calls _make_init()
+Factory = None
+
 
 class _Nothing(object):
  """
@@ -848,22 +852,38 @@ def add_hash(self):
 
  return self
 
- def add_init(self):
- self._cls_dict["__init__"] = self._add_method_dunders(
- _make_init(
- self._cls,
- self._attrs,
- self._has_post_init,
- self._frozen,
- self._slots,
- self._cache_hash,
- self._base_attr_map,
- self._is_exc,
+ def add_init(self, init, auto_detect):
+ should_implement_init = _determine_whether_to_implement(
+ self._cls, init, auto_detect, ("__init__",)
+ )
+ attrs_init_method, init_method = _make_init(
+ self._cls,
+ self._attrs,
+ self._has_post_init,
+ self._frozen,
+ self._slots,
+ self._cache_hash,
+ self._base_attr_map,
+ self._is_exc,
+ (
  self._on_setattr is not None
- and self._on_setattr is not setters.NO_OP,
- )
+ and self._on_setattr is not setters.NO_OP
+ ),
+ should_implement_init,
  )
 
+ self._cls_dict["__attrs_init__"] = self._add_method_dunders(
+ attrs_init_method
+ )
+ if init_method is not None:
+ self._cls_dict["__init__"] = self._add_method_dunders(init_method)
+ else:
+ if self._cache_hash:
+ raise TypeError(
+ "Invalid value for cache_hash. To use hash caching,"
+ " init must be True."
+ )
+
  return self
 
  def add_eq(self):
@@ -1367,17 +1387,7 @@ def wrap(cls):
  )
  builder.make_unhashable()
 
- if _determine_whether_to_implement(
- cls, init, auto_detect, ("__init__",)
- ):
- builder.add_init()
- else:
- if cache_hash:
- raise TypeError(
- "Invalid value for cache_hash. To use hash caching,"
- " init must be True."
- )
-
+ builder.add_init(init, auto_detect)
  return builder.build_class()
 
  # maybe_cls's type depends on the usage of the decorator. It's a class
@@ -1836,6 +1846,7 @@ def _make_init(
  base_attr_map,
  is_exc,
  has_global_on_setattr,
+ should_implement_init,
 ):
  if frozen and has_global_on_setattr:
  raise ValueError("Frozen classes can't use on_setattr.")
@@ -1872,6 +1883,7 @@ def _make_init(
  is_exc,
  needs_cached_setattr,
  has_global_on_setattr,
+ should_implement_init,
  )
  locs = {}
  bytecode = compile(script, unique_filename, "exec")
@@ -1893,10 +1905,16 @@ def _make_init(
  unique_filename,
  )
 
- __init__ = locs["__init__"]
- __init__.__annotations__ = annotations
+ __attrs_init__ = locs["__attrs_init__"]
+ __attrs_init__.__annotations__ = annotations
+
+ if "__init__" in locs:
+ __init__ = locs["__init__"]
+ __init__.__annotations__ = annotations
+ else:
+ __init__ = None
 
- return __init__
+ return __attrs_init__, __init__
 
 
 def _setattr(attr_name, value_var, has_on_setattr):
@@ -2011,6 +2029,7 @@ def _attrs_to_init_script(
  is_exc,
  needs_cached_setattr,
  has_global_on_setattr,
+ should_implement_init,
 ):
  """
  Return a script of an initializer for *attrs* and a dict of globals.
@@ -2084,7 +2103,7 @@ def fmt_setter_with_converter(
  )
  arg_name = a.name.lstrip("_")
 
- has_factory = isinstance(a.default, Factory)
+ has_factory = Factory is not None and isinstance(a.default, Factory)
  if has_factory and a.default.takes_self:
  maybe_self = "self"
  else:
@@ -2225,9 +2244,6 @@ def fmt_setter_with_converter(
  names_for_globals[val_name] = a.validator
  names_for_globals[attr_name] = a
 
- if post_init:
- lines.append("self.__attrs_post_init__()")
-
  # because this is set only after __attrs_post_init is called, a crash
  # will result if post-init tries to access the hash code. This seemed
  # preferable to setting this beforehand, in which case alteration to
@@ -2263,12 +2279,30 @@ def fmt_setter_with_converter(
  ", " if args else "", # leading comma
  ", ".join(kw_only_args), # kw_only args
  )
+
+ init_lines = ""
+ if should_implement_init:
+ init_lines = """\
+
+def __init__(self, {args}):
+ args = locals()
+ del args['self']
+ self.__attrs_init__(**args)
+ {post_init_call}
+""".format(
+ args=args,
+ post_init_call="self.__attrs_post_init__()" if post_init else "",
+ )
+
  return (
  """\
-def __init__(self, {args}):
+def __attrs_init__(self, {args}):
  {lines}
+{init_lines}
 """.format(
- args=args, lines="\n ".join(lines) if lines else "pass"
+ args=args,
+ lines="\n ".join(lines) if lines else "pass",
+ init_lines=init_lines,
  ),
  names_for_globals,
  annotations,

tests/test_dunders.py

@@ -59,7 +59,7 @@ def _add_init(cls, frozen):
  This function used to be part of _make. It wasn't used anymore however
  the tests for it are still useful to test the behavior of _make_init.
  """
- cls.__init__ = _make_init(
+ cls.__attrs_init__, cls.__init__ = _make_init(
  cls,
  cls.__attrs_attrs__,
  getattr(cls, "__attrs_post_init__", False),
@@ -69,6 +69,7 @@ def _add_init(cls, frozen):
  base_attr_map={},
  is_exc=False,
  has_global_on_setattr=False,
+ should_implement_init=True,
  )
  return cls
 

tests/test_make.py

@@ -1526,7 +1526,7 @@ class C(object):
  b.add_eq()
  .add_order()
  .add_hash()
- .add_init()
+ .add_init(True, True)
  .add_repr("ns")
  .add_str()
  .build_class()