TYP: fix typing errors for mypy==0.790, bump mypy version

doc/source/whatsnew/v1.3.0.rst

@@ -88,7 +88,7 @@ If installed, we now require:
 +-----------------+-----------------+----------+---------+
 | pytest (dev)    | 5.0.1           |          |         |
 +-----------------+-----------------+----------+---------+
-| mypy (dev)      | 0.782           |          |         |
+| mypy (dev)      | 0.790           |          |    X    |
 +-----------------+-----------------+----------+---------+
 
 For `optional libraries <https://dev.pandas.io/docs/install.html#dependencies>`_ the general recommendation is to use the latest version.

environment.yml

@@ -23,7 +23,7 @@ dependencies:
   - flake8
   - flake8-comprehensions>=3.1.0  # used by flake8, linting of unnecessary comprehensions
   - isort>=5.2.1  # check that imports are in the right order
-  - mypy=0.782
+  - mypy=0.790
   - pre-commit>=2.9.2
   - pycodestyle  # used by flake8
   - pyupgrade

pandas/core/computation/parsing.py

@@ -38,10 +38,7 @@ def create_valid_python_identifier(name: str) -> str:
     # token.tok_name contains a readable description of the replacement string.
     special_characters_replacements = {
         char: f"_{token.tok_name[tokval]}_"
-        # The ignore here is because of a bug in mypy that is resolved in 0.740
-        for char, tokval in (
-            tokenize.EXACT_TOKEN_TYPES.items()  # type: ignore[attr-defined]
-        )
+        for char, tokval in (tokenize.EXACT_TOKEN_TYPES.items())
     }
     special_characters_replacements.update(
         {

pandas/core/groupby/ops.py

@@ -283,8 +283,8 @@ def groups(self) -> Dict[Hashable, np.ndarray]:
             return self.groupings[0].groups
         else:
             to_groupby = zip(*(ping.grouper for ping in self.groupings))
-            to_groupby = Index(to_groupby)
-            return self.axis.groupby(to_groupby)
+            index = Index(to_groupby)
+            return self.axis.groupby(index)
 
     @final
     @cache_readonly

pandas/io/common.py

@@ -179,7 +179,8 @@ def stringify_path(
         # this function with convert_file_like=True to infer the compression.
         return cast(FileOrBuffer[AnyStr], filepath_or_buffer)
 
-    if isinstance(filepath_or_buffer, os.PathLike):
+    # Only @runtime_checkable protocols can be used with instance and class checks
+    if isinstance(filepath_or_buffer, os.PathLike):  # type: ignore[misc]
         filepath_or_buffer = filepath_or_buffer.__fspath__()
     return _expand_user(filepath_or_buffer)
 
@@ -487,9 +488,15 @@ def infer_compression(
     if compression in _compression_to_extension:
         return compression
 
-    msg = f"Unrecognized compression type: {compression}"
-    valid = ["infer", None] + sorted(_compression_to_extension)
-    msg += f"\nValid compression types are {valid}"
+    # https://github.com/python/mypy/issues/5492
+    # Unsupported operand types for + ("List[Optional[str]]" and "List[str]")
+    valid = ["infer", None] + sorted(
+        _compression_to_extension
+    )  # type: ignore[operator]
+    msg = (
+        f"Unrecognized compression type: {compression}\n"
+        f"Valid compression types are {valid}"
+    )
     raise ValueError(msg)
 
 

requirements-dev.txt

@@ -11,7 +11,7 @@ cpplint
 flake8
 flake8-comprehensions>=3.1.0
 isort>=5.2.1
-mypy==0.782
+mypy==0.790
 pre-commit>=2.9.2
 pycodestyle
 pyupgrade