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fix(io): update Reader.read to respect Liskov Substitution Principle #23

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Merged
cesarcoatl merged 2 commits into from
Apr 17, 2026
Merged

fix(io): update Reader.read to respect Liskov Substitution Principle #23

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b4608eb
fix(io): update Reader.read to respect Liskov Substitution Principle
cesarcoatl Apr 17, 2026
81d5c67
fix(io): import CharBuffer from java.nio
cesarcoatl Apr 17, 2026
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5 changes: 3 additions & 2 deletions src/java/io/__init__.py
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Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,7 @@
Readable,
Throwable,
)
from java.nio import CharBuffer
from java.nio.channels import FileChannel
from java.nio.charset import Charset, CharsetDecoder

Expand Down Expand Up @@ -334,8 +335,8 @@ def nullReader():
# type: () -> Reader
pass

def read(self, *args):
# type: (*Any) -> int
def read(self, cb):
# type: (CharBuffer) -> int
pass

def ready(self):
Expand Down
3 changes: 2 additions & 1 deletion stubs/stubs/java/io/__init__.pyi
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@ from java.lang import (
Readable,
Throwable,
)
from java.nio import CharBuffer
from java.nio.channels import FileChannel
from java.nio.charset import Charset, CharsetDecoder

Expand Down Expand Up @@ -112,7 +113,7 @@ class Reader(Object, Readable, Closeable):
def markSupported(self) -> bool: ...
@staticmethod
def nullReader() -> Reader: ...
def read(self, *args: Any) -> int: ...
def read(self, cb: CharBuffer) -> int: ...
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@sourcery-ai sourcery-ai Bot Apr 17, 2026

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suggestion: The stub now models only a single read(CharBuffer) shape; consider overloads if other read variants are intended.

The old *args: Any signature was imprecise but did indicate multiple read variants. If this stub is meant to cover the full Java API (e.g., read(), read(char[], int, int)), representing each as an explicit @overload would be more accurate than a single read(self, cb: CharBuffer) -> int signature.

Suggested implementation:

    @staticmethod
    def nullReader() -> Reader: ...

    @overload
    def read(self) -> int: ...
    @overload
    def read(self, cb: CharBuffer) -> int: ...
    @overload
    def read(self, cbuf: list[str]) -> int: ...
    @overload
    def read(self, cbuf: list[str], off: int, length: int) -> int: ...

    def ready(self) -> bool: ...

`.

Here are the edits:

<file_operations>
<file_operation operation="edit" file_path="stubs/stubs/java/io/init.pyi">
<<<<<<< SEARCH
@staticmethod
def nullReader() -> Reader: ...
def read(self, cb: CharBuffer) -> int: ...
def ready(self) -> bool: ...

@staticmethod
def nullReader() -> Reader: ...

@overload
def read(self) -> int: ...
@overload
def read(self, cb: CharBuffer) -> int: ...
@overload
def read(self, cbuf: list[str]) -> int: ...
@overload
def read(self, cbuf: list[str], off: int, length: int) -> int: ...

def ready(self) -> bool: ...

REPLACE
</file_operation>
</file_operations>

<additional_changes>

  1. Ensure from typing import overload is present at the top of stubs/stubs/java/io/__init__.pyi. If the file already imports from typing, extend that import to include overload.
  2. If your codebase uses a different type to model Java char[] (e.g., Sequence[str] or a custom CharArray), adjust the cbuf: list[str] annotations accordingly to match your existing conventions.

def ready(self) -> bool: ...
def reset(self) -> None: ...
def skip(self, n: long) -> long: ...
Expand Down