add-trailing-comma

add-trailing-comma

python -m add_trailing_comma

from add_trailing_comma._main import main, fix_file

# Process single file
add-trailing-comma script.py

# Process multiple files
add-trailing-comma file1.py file2.py src/

# Read from stdin
cat script.py | add-trailing-comma -

# Exit with 0 even if files were changed (useful for CI)
add-trailing-comma --exit-zero-even-if-changed file.py

-   repo: https://github.com/asottile/add-trailing-comma
    rev: v3.2.0
    hooks:
    -   id: add-trailing-comma

import argparse
from add_trailing_comma._main import fix_file, main

# Process a single file using internal API
args = argparse.Namespace(exit_zero_even_if_changed=False)
result = fix_file("script.py", args)

# Use main function with arguments
result = main(["script.py", "--exit-zero-even-if-changed"])

def main(argv: Sequence[str] | None = None) -> int:
    """
    Main entry point for command line interface.
    
    Parameters:
    - argv: Command line arguments (defaults to sys.argv if None)
    
    Returns:
    int: Exit code (0 for success or no changes, 1 for errors or changes made)
    
    Available command line options:
    - filenames: List of files to process
    - --exit-zero-even-if-changed: Exit with 0 even if files were modified
    - --py35-plus, --py36-plus: Legacy flags (deprecated, no effect)
    """

def fix_file(filename: str, args: argparse.Namespace) -> int:
    """
    Process a single file to add trailing commas.
    
    Parameters:
    - filename: Path to file to process, or '-' for stdin
    - args: Namespace with configuration options (requires exit_zero_even_if_changed attribute)
    
    Returns:
    int: 1 if file was changed or error occurred, 0 if no changes or exit_zero_even_if_changed=True
    
    Handles:
    - Unicode decode errors (prints error message, returns 1)
    - Syntax errors (returns content unchanged)
    - File I/O operations for both files and stdin
    """

def _fix_src(contents_text: str) -> str:
    """
    Internal function that applies AST transformations to add trailing commas.
    
    Note: This is a private function (prefix '_') and should not be used in 
    production code as it may change without notice.
    
    Parameters:
    - contents_text: Python source code as string
    
    Returns:
    str: Transformed source code with trailing commas added
    
    Raises:
    SyntaxError: Returns original content if syntax errors are encountered
    """

# Before
function_call(
    argument,
    5 ** 5,
    kwarg=foo
)

# After  
function_call(
    argument,
    5 ** 5,
    kwarg=foo,
)

# Lists
x = [
    1, 2, 3,  # trailing comma added
]

# Tuples
y = (
    'a', 'b', 'c',  # trailing comma added
)

# Dictionaries
config = {
    'key1': 'value1',
    'key2': 'value2',  # trailing comma added
}

# Sets
items = {
    'item1',
    'item2',  # trailing comma added
}

def func(
        arg1,
        arg2,  # trailing comma added
):
    pass

async def async_func(
        arg1,
        arg2,  # trailing comma added
):
    pass

from os import (
    path,
    makedirs,  # trailing comma added
)

class MyClass(
    Base1,
    Base2,  # trailing comma added
):
    pass

with (
        open('f1', 'r') as f1,
        open('f2', 'w') as f2,  # trailing comma added
):
    pass

match x:
    case A(
       1,
       2,  # trailing comma added
    ):
        pass
    case (
       1,
       2,  # trailing comma added
    ):
        pass
    case [
       1,
       2,  # trailing comma added
    ]:
        pass
    case {
       'x': 1,
       'y': 2,  # trailing comma added
    }:
        pass

def f[
    T,  # trailing comma added
](x: T) -> T:
    return x

class A[
    K,  # trailing comma added
]:
    def __init__(self, x: K) -> None:
        self.x = x

type ListOrSet[
     T,  # trailing comma added
] = list[T] | set[T]

# Unhug trailing paren
x(
    arg1,
    arg2,  # trailing comma and proper closing
)

# Unhug leading paren
function_name(
    arg1,
    arg2,
)

# Match closing brace indentation
x = [
    1,
    2,
    3,
]  # proper indentation

# Before
[1, 2, 3,]
[1, 2, 3, ]

# After
[1, 2, 3]
[1, 2, 3]

# Required external dependency
from tokenize_rt import src_to_tokens, tokens_to_src, Token, Offset

# Standard library dependencies
from typing import Sequence, Iterable
from collections.abc import Sequence
from argparse import Namespace, ArgumentParser
import ast
import sys

# Main API functions
def main(argv: Sequence[str] | None = None) -> int
def fix_file(filename: str, args: Namespace) -> int

# Internal transformation function
def _fix_src(contents_text: str) -> str

# Helper types from tokenize-rt
Token: # Represents a token with .src, .name, .offset attributes
Offset: # Represents position in source (line, column)