bind input type of encding and mode with the returned type; removed i…

…gnore statements (mypy will compile about filepath_or_buffer)

pandas/_typing.py

@@ -1,3 +1,4 @@
+from dataclasses import dataclass
 from datetime import datetime, timedelta, tzinfo
 from pathlib import Path
 from typing import (
@@ -8,6 +9,7 @@
  Callable,
  Collection,
  Dict,
+ Generic,
  Hashable,
  List,
  Mapping,
@@ -117,7 +119,13 @@
 CompressionOptions = Optional[Union[str, CompressionDict]]
 
 
-class IOargs(NamedTuple):
+# lets us bind types
+ModeVar = TypeVar("ModeVar", str, None)
+EncodingVar = TypeVar("EncodingVar", str, None)
+
+
+@dataclass
+class IOargs(Generic[ModeVar, EncodingVar]):
  """
  Return value of io/common.py:get_filepath_or_buffer.
 
@@ -128,7 +136,7 @@ class IOargs(NamedTuple):
  """
 
  filepath_or_buffer: FilePathOrBuffer
- encoding: Optional[str]
- compression: CompressionOptions = None
- should_close: bool = False
- mode: Optional[str] = None
+ encoding: EncodingVar
+ compression: CompressionOptions
+ should_close: bool
+ mode: Union[ModeVar, str]

pandas/core/frame.py

@@ -2281,7 +2281,7 @@ def to_markdown(
  result = tabulate.tabulate(self, **kwargs)
  if buf is None:
  return result
- buf, _, _, should_close, _ = get_filepath_or_buffer( # type: ignore
+ buf, _, _, should_close, _ = get_filepath_or_buffer(
  buf, mode=mode, storage_options=storage_options
  )
  assert not isinstance(buf, str)

pandas/core/generic.py

@@ -3249,7 +3249,7 @@ def to_csv(
  formatter.save()
 
  if path_or_buf is None:
- return formatter.path_or_buf.getvalue() # type: ignore
+ return formatter.path_or_buf.getvalue()
 
  return None
 

pandas/io/common.py

@@ -33,8 +33,11 @@
 from pandas._typing import (
  CompressionDict,
  CompressionOptions,
+ EncodingVar,
  FilePathOrBuffer,
+ FilePathOrBufferVar,
  IOargs,
+ ModeVar,
  StorageOptions,
 )
 from pandas.compat import _get_lzma_file, _import_lzma
@@ -166,11 +169,11 @@ def is_fsspec_url(url: FilePathOrBuffer) -> bool:
 
 def get_filepath_or_buffer(
  filepath_or_buffer: FilePathOrBuffer,
- encoding: Optional[str] = None,
+ encoding: EncodingVar = None, # type: ignore[assignment]
  compression: CompressionOptions = None,
- mode: Optional[str] = None,
+ mode: ModeVar = None, # type: ignore[assignment]
  storage_options: StorageOptions = None,
-) -> IOargs:
+) -> IOargs[ModeVar, EncodingVar]:
  """
  If the filepath_or_buffer is a url, translate and return the buffer.
  Otherwise passthrough.

pandas/io/formats/csvs.py

@@ -64,13 +64,7 @@ def __init__(
  compression, self.compression_args = get_compression_method(compression)
  self.compression = infer_compression(path_or_buf, compression)
 
- (
- self.path_or_buf,
- _,
- _,
- self.should_close,
- mode, # type: ignore
- ) = get_filepath_or_buffer(
+ (self.path_or_buf, _, _, self.should_close, mode,) = get_filepath_or_buffer(
  path_or_buf,
  encoding=encoding,
  compression=self.compression,

pandas/io/json/_json.py

@@ -645,7 +645,7 @@ def read_json(
 
  result = json_reader.read()
  if should_close:
- filepath_or_buffer.close() # type: ignore
+ filepath_or_buffer.close()
 
  return result
 

pandas/io/parsers.py

@@ -462,7 +462,7 @@ def _read(filepath_or_buffer: FilePathOrBuffer, kwds):
 
  if should_close:
  try:
- fp_or_buf.close() # type: ignore
+ fp_or_buf.close()
  except ValueError:
  pass
 

pandas/io/pickle.py

@@ -107,7 +107,7 @@ def to_pickle(
  _f.close()
  if should_close:
  try:
- fp_or_buf.close() # type: ignore
+ fp_or_buf.close()
  except ValueError:
  pass