validate_string_concatenation.py

#!/usr/bin/env python
"""
Unwanted patterns test cases.
"""

import argparse
import os
import sys
import token
import tokenize
from typing import Callable, Generator, List, Tuple

FILE_EXTENSIONS_TO_CHECK = (".py", ".pyx", ".pyx.ini", ".pxd")


def main(
    function: Callable[[str], Generator[Tuple[str, int, str], None, None]],
    source_path: str,
    output_format: str,
) -> bool:
    """
    Main entry point of the script.

    Parameters
    ----------
    function : Callable
        Function to execute for the test case.
    source_path : str
        Source path representing path to a file/directory.
    output_format : str
        Output format of the error message.

    Returns
    -------
    bool
        True if found any patterns are found related to the given function.

    Raises
    ------
    ValueError
        If the `source_path` is not pointing to existing file/directory.
    """
    if not os.path.exists(source_path):
        raise ValueError(
            "Please enter a valid path, pointing to a valid file/directory."
        )

    is_failed: bool = False

    if os.path.isfile(source_path):
        for source_path, line_number, msg in function(source_path):
            is_failed = True
            print(
                output_format.format(
                    source_path=source_path, line_number=line_number, msg=msg
                )
            )

    for subdir, _, files in os.walk(source_path):
        for file_name in files:
            if any(
                file_name.endswith(extension) for extension in FILE_EXTENSIONS_TO_CHECK
            ):
                for source_path, line_number, msg in function(
                    os.path.join(subdir, file_name)
                ):
                    is_failed = True
                    print(
                        output_format.format(
                            source_path=source_path, line_number=line_number, msg=msg
                        )
                    )
    return is_failed


def strings_to_concatenate(
    source_path: str,
) -> Generator[Tuple[str, int, str], None, None]:
    """
    This test case is necessary after 'Black' (https://github.com/psf/black),
    is formating strings over multiple lines.

    For example, when this:

    >>> foo = (
    ...        "bar "
    ...        "baz"
    ... )

    Is becoming this:

    >>> foo = ("bar " "baz")

    'Black' is not considering this as an
    issue (see https://github.com/psf/black/issues/1051),
    so we are checking it here instead.

    Parameters
    ----------
    source_path : str
        File path pointing to a single file.

    Yields
    ------
    source_path : str
        Source file path.
    line_number : int
        Line number of unconcatenated string.
    MSG : str
        Explenation of the error.

    Notes
    -----
    GH #30454
    """
    MSG: str = (
        "String unnecessarily split in two by black. Please merge them manually."
    )

    with open(source_path, "r") as file_name:
        tokens: List = list(tokenize.generate_tokens(file_name.readline))

    for current_token, next_token in zip(tokens, tokens[1:]):
        if current_token[0] == next_token[0] == token.STRING:
            yield source_path, current_token[2][0], MSG


def strings_with_wrong_placed_space(
    source_path: str,
) -> Generator[Tuple[str, int, str], None, None]:
    """
    Test case for leading spaces in concated strings.

    For example:

    >>> foo = (
    ...    "bar "
    ...    "baz"
    ... )

    Instead of:

    >>> foo = (
    ...        "bar"
    ...       " baz"
    ... )

    Parameters
    ----------
    source_path : str
        File path pointing to a single file.

    Yields
    ------
    source_path : str
        Source file path.
    line_number : int
        Line number of unconcatenated string.
    MSG : str
        Explenation of the error.
    """
    MSG: str = (
        "String has a space at the beginning "
        "instead of the end of the previous string."
    )

    with open(source_path, "r") as file_name:
        tokens: List = list(tokenize.generate_tokens(file_name.readline))

    for first_token, second_token, third_token in zip(tokens, tokens[1:], tokens[2:]):
        if (
            first_token[0] == third_token[0] == token.STRING
            and second_token[0] == token.NL
        ):
            # Means we are in a block of concated string

            # Striping the quotes
            first_string = first_token[1][1:-1]
            second_string = third_token[1][1:-1]

            if (not first_string.endswith(" ")) and (second_string.startswith(" ")):
                yield source_path, third_token[2][0], MSG


def bare_pytest_raises(source_path: str) -> Generator[Tuple[str, int, str], None, None]:
    """
    Test Case for bare pytest raises.

    For example:

    >>> with pytest.raise(ValueError):
    ...     # Some code that raises ValueError

    Instead of:

    >>> with pytest.raise(ValueError, match="foo"):
    ...     # Some code that raises ValueError

    Parameters
    ----------
    source_path : str
        File path pointing to a single file.

    Yields
    ------
    source_path : str
        Source file path.
    line_number : int
        Line number of unconcatenated string.
    MSG : str
        Explenation of the error.

    Notes
    -----
    GH #23922
    """
    MSG: str = "Bare pytests raise have been found."

    with open(source_path, "r") as file_name:
        tokens: List = list(tokenize.generate_tokens(file_name.readline))

    for counter, current_token in enumerate(tokens, start=1):
        if current_token[0] == token.NAME and current_token[1] == "raises":
            for next_token in tokens[counter:]:
                if next_token[0] == token.NAME and next_token[1] == "match":
                    break
                if next_token[0] == token.NEWLINE:
                    yield source_path, current_token[2][0], MSG
                    break


if __name__ == "__main__":
    FUNCTIONS_MAP = {
        "strings_to_concatenate": strings_to_concatenate,
        "strings_with_wrong_placed_space": strings_with_wrong_placed_space,
        "bare_pytest_raises": bare_pytest_raises,
    }

    parser = argparse.ArgumentParser(description="Unwanted patterns checker.")

    parser.add_argument(
        "path", nargs="?", default=".", help="Source path of file/directory to check."
    )
    parser.add_argument(
        "--format",
        "-f",
        default="{source_path}:{line_number}:{msg}.",
        help="Output format of the error message.",
    )
    parser.add_argument(
        "--id", "-i", choices=FUNCTIONS_MAP.keys(), help="Test case to check."
    )

    args = parser.parse_args()

    sys.exit(
        main(
            function=FUNCTIONS_MAP[args.id],
            source_path=args.path,
            output_format=args.format,
        )
    )