Fix mypy in `utilities.parsing` (#8132)

pytorch_lightning/utilities/parsing.py

@@ -17,8 +17,11 @@ import pickle
 import types
 from argparse import Namespace
 from dataclasses import fields, is_dataclass
-from typing import Any, Dict, Optional, Sequence, Tuple, Union
+from typing import Any, Dict, List, Optional, Sequence, Tuple, Type, Union
 
+from typing_extensions import Literal
+
+import pytorch_lightning as pl
 from pytorch_lightning.utilities.warnings import rank_zero_warn
 
 
@@ -53,10 +56,10 @@ def str_to_bool(val: str) -> bool:
     >>> str_to_bool('FALSE')
     False
     """
-    val = str_to_bool_or_str(val)
-    if isinstance(val, bool):
-        return val
-    raise ValueError(f'invalid truth value {val}')
+    val_converted = str_to_bool_or_str(val)
+    if isinstance(val_converted, bool):
+        return val_converted
+    raise ValueError(f'invalid truth value {val_converted}')
 
 
 def str_to_bool_or_int(val: str) -> Union[bool, int, str]:
@@ -71,13 +74,13 @@ def str_to_bool_or_int(val: str) -> Union[bool, int, str]:
     >>> str_to_bool_or_int("abc")
     'abc'
     """
-    val = str_to_bool_or_str(val)
-    if isinstance(val, bool):
-        return val
+    val_converted = str_to_bool_or_str(val)
+    if isinstance(val_converted, bool):
+        return val_converted
     try:
-        return int(val)
+        return int(val_converted)
     except ValueError:
-        return val
+        return val_converted
 
 
 def is_picklable(obj: object) -> bool:
@@ -90,7 +93,7 @@ def is_picklable(obj: object) -> bool:
         return False
 
 
-def clean_namespace(hparams):
+def clean_namespace(hparams: Union[Dict[str, Any], Namespace]) -> None:
     """Removes all unpicklable entries from hparams"""
 
     hparams_dict = hparams
@@ -104,7 +107,7 @@ def clean_namespace(hparams):
         del hparams_dict[k]
 
 
-def parse_class_init_keys(cls) -> Tuple[str, str, str]:
+def parse_class_init_keys(cls: Type['pl.LightningModule']) -> Tuple[str, Optional[str], Optional[str]]:
     """Parse key words for standard self, *args and **kwargs
 
     >>> class Model():
@@ -120,10 +123,14 @@ def parse_class_init_keys(cls) -> Tuple[str, str, str]:
     # self is always first
     n_self = init_params[0].name
 
-    def _get_first_if_any(params, param_type):
+    def _get_first_if_any(
+        params: List[inspect.Parameter],
+        param_type: Literal[inspect._ParameterKind.VAR_POSITIONAL, inspect._ParameterKind.VAR_KEYWORD],
+    ) -> Optional[str]:
         for p in params:
             if p.kind == param_type:
                 return p.name
+        return None
 
     n_args = _get_first_if_any(init_params, inspect.Parameter.VAR_POSITIONAL)
     n_kwargs = _get_first_if_any(init_params, inspect.Parameter.VAR_KEYWORD)
@@ -131,7 +138,7 @@ def parse_class_init_keys(cls) -> Tuple[str, str, str]:
     return n_self, n_args, n_kwargs
 
 
-def get_init_args(frame) -> dict:
+def get_init_args(frame: types.FrameType) -> Dict[str, Any]:
     _, _, _, local_vars = inspect.getargvalues(frame)
     if '__class__' not in local_vars:
         return {}
@@ -142,12 +149,18 @@ def get_init_args(frame) -> dict:
     exclude_argnames = (*filtered_vars, '__class__', 'frame', 'frame_args')
     # only collect variables that appear in the signature
     local_args = {k: local_vars[k] for k in init_parameters.keys()}
-    local_args.update(local_args.get(kwargs_var, {}))
+    # kwargs_var might be None => raised an error by mypy
+    if kwargs_var:
+        local_args.update(local_args.get(kwargs_var, {}))
     local_args = {k: v for k, v in local_args.items() if k not in exclude_argnames}
     return local_args
 
 
-def collect_init_args(frame, path_args: list, inside: bool = False) -> list:
+def collect_init_args(
+    frame: types.FrameType,
+    path_args: List[Dict[str, Any]],
+    inside: bool = False,
+) -> List[Dict[str, Any]]:
     """
     Recursively collects the arguments passed to the child constructors in the inheritance tree.
 
@@ -162,6 +175,10 @@ def collect_init_args(frame, path_args: list, inside: bool = False) -> list:
           most specific class in the hierarchy.
     """
     _, _, _, local_vars = inspect.getargvalues(frame)
+    # frame.f_back must be of a type types.FrameType for get_init_args/collect_init_args due to mypy
+    if not isinstance(frame.f_back, types.FrameType):
+        return path_args
+
     if '__class__' in local_vars:
         local_args = get_init_args(frame)
         # recursive update
@@ -172,7 +189,7 @@ def collect_init_args(frame, path_args: list, inside: bool = False) -> list:
     return path_args
 
 
-def flatten_dict(source, result=None):
+def flatten_dict(source: Dict[str, Any], result: Optional[Dict[str, Any]] = None) -> Dict[str, Any]:
     if result is None:
         result = {}
 
@@ -187,7 +204,7 @@ def flatten_dict(source, result=None):
 
 def save_hyperparameters(
     obj: Any,
-    *args,
+    *args: Any,
     ignore: Optional[Union[Sequence[str], str]] = None,
     frame: Optional[types.FrameType] = None
 ) -> None:
@@ -198,7 +215,12 @@ def save_hyperparameters(
         return
 
     if not frame:
-        frame = inspect.currentframe().f_back
+        current_frame = inspect.currentframe()
+        # inspect.currentframe() return type is Optional[types.FrameType]: current_frame.f_back called only if available
+        if current_frame:
+            frame = current_frame.f_back
+    if not isinstance(frame, types.FrameType):
+        raise AttributeError("There is no `frame` available while being required.")
 
     if is_dataclass(obj):
         init_args = {f.name: getattr(obj, f.name) for f in fields(obj)}
@@ -251,16 +273,16 @@ class AttributeDict(Dict):
     "my-key":  3.14
     """
 
-    def __getattr__(self, key):
+    def __getattr__(self, key: str) -> Optional[Any]:
         try:
             return self[key]
         except KeyError as exp:
             raise AttributeError(f'Missing attribute "{key}"') from exp
 
-    def __setattr__(self, key, val):
+    def __setattr__(self, key: str, val: Any) -> None:
         self[key] = val
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         if not len(self):
             return ""
         max_key_length = max([len(str(k)) for k in self])
@@ -270,14 +292,14 @@ class AttributeDict(Dict):
         return out
 
 
-def _lightning_get_all_attr_holders(model, attribute):
+def _lightning_get_all_attr_holders(model: 'pl.LightningModule', attribute: str) -> List[Any]:
     """
     Special attribute finding for Lightning. Gets all of the objects or dicts that holds attribute.
     Checks for attribute in model namespace, the old hparams namespace/dict, and the datamodule.
     """
     trainer = getattr(model, 'trainer', None)
 
-    holders = []
+    holders: List[Any] = []
 
     # Check if attribute in model
     if hasattr(model, attribute):
@@ -295,7 +317,7 @@ def _lightning_get_all_attr_holders(model, attribute):
     return holders
 
 
-def _lightning_get_first_attr_holder(model, attribute):
+def _lightning_get_first_attr_holder(model: 'pl.LightningModule', attribute: str) -> Optional[Any]:
     """
     Special attribute finding for Lightning.  Gets the object or dict that holds attribute, or None.
     Checks for attribute in model namespace, the old hparams namespace/dict, and the datamodule,
@@ -308,7 +330,7 @@ def _lightning_get_first_attr_holder(model, attribute):
     return holders[-1]
 
 
-def lightning_hasattr(model, attribute):
+def lightning_hasattr(model: 'pl.LightningModule', attribute: str) -> bool:
     """
     Special hasattr for Lightning. Checks for attribute in model namespace,
     the old hparams namespace/dict, and the datamodule.
@@ -316,7 +338,7 @@ def lightning_hasattr(model, attribute):
     return _lightning_get_first_attr_holder(model, attribute) is not None
 
 
-def lightning_getattr(model, attribute):
+def lightning_getattr(model: 'pl.LightningModule', attribute: str) -> Optional[Any]:
     """
     Special getattr for Lightning. Checks for attribute in model namespace,
     the old hparams namespace/dict, and the datamodule.
@@ -338,7 +360,7 @@ def lightning_getattr(model, attribute):
     return getattr(holder, attribute)
 
 
-def lightning_setattr(model, attribute, value):
+def lightning_setattr(model: 'pl.LightningModule', attribute: str, value: Any) -> None:
     """
     Special setattr for Lightning. Checks for attribute in model namespace
     and the old hparams namespace/dict.

setup.cfg

@@ -185,6 +185,8 @@ ignore_errors = True
 ignore_errors = False
 [mypy-pytorch_lightning.utilities.device_parser]
 ignore_errors = False
+[mypy-pytorch_lightning.utilities.parsing]
+ignore_errors = False
 
 # todo: add proper typing to this module...
 [mypy-pl_examples.*]