import io import json import platform import re import sys import tokenize import traceback from collections.abc import ( Collection, Generator, Iterator, MutableMapping, Sequence, ) from contextlib import contextmanager from dataclasses import replace from datetime import datetime, timezone from enum import Enum from json.decoder import JSONDecodeError from pathlib import Path from re import Pattern from typing import Any, Optional, Union import click from click.core import ParameterSource from mypy_extensions import mypyc_attr from pathspec import PathSpec from pathspec.patterns.gitwildmatch import GitWildMatchPatternError from _black_version import version as __version__ from black.cache import Cache from black.comments import normalize_fmt_off from black.const import ( DEFAULT_EXCLUDES, DEFAULT_INCLUDES, DEFAULT_LINE_LENGTH, STDIN_PLACEHOLDER, ) from black.files import ( best_effort_relative_path, find_project_root, find_pyproject_toml, find_user_pyproject_toml, gen_python_files, get_gitignore, parse_pyproject_toml, path_is_excluded, resolves_outside_root_or_cannot_stat, wrap_stream_for_windows, ) from black.handle_ipynb_magics import ( PYTHON_CELL_MAGICS, jupyter_dependencies_are_installed, mask_cell, put_trailing_semicolon_back, remove_trailing_semicolon, unmask_cell, validate_cell, ) from black.linegen import LN, LineGenerator, transform_line from black.lines import EmptyLineTracker, LinesBlock from black.mode import FUTURE_FLAG_TO_FEATURE, VERSION_TO_FEATURES, Feature from black.mode import Mode as Mode # re-exported from black.mode import Preview, TargetVersion, supports_feature from black.nodes import STARS, is_number_token, is_simple_decorator_expression, syms from black.output import color_diff, diff, dump_to_file, err, ipynb_diff, out from black.parsing import ( # noqa F401 ASTSafetyError, InvalidInput, lib2to3_parse, parse_ast, stringify_ast, ) from black.ranges import ( adjusted_lines, convert_unchanged_lines, parse_line_ranges, sanitized_lines, ) from black.report import Changed, NothingChanged, Report from blib2to3.pgen2 import token from blib2to3.pytree import Leaf, Node COMPILED = Path(__file__).suffix in (".pyd", ".so") # types FileContent = str Encoding = str NewLine = str class WriteBack(Enum): NO = 0 YES = 1 DIFF = 2 CHECK = 3 COLOR_DIFF = 4 @classmethod def from_configuration( cls, *, check: bool, diff: bool, color: bool = False ) -> "WriteBack": if check and not diff: return cls.CHECK if diff and color: return cls.COLOR_DIFF return cls.DIFF if diff else cls.YES # Legacy name, left for integrations. FileMode = Mode def read_pyproject_toml( ctx: click.Context, param: click.Parameter, value: Optional[str] ) -> Optional[str]: """Inject Black configuration from "pyproject.toml" into defaults in `ctx`. Returns the path to a successfully found and read configuration file, None otherwise. """ if not value: value = find_pyproject_toml( ctx.params.get("src", ()), ctx.params.get("stdin_filename", None) ) if value is None: return None try: config = parse_pyproject_toml(value) except (OSError, ValueError) as e: raise click.FileError( filename=value, hint=f"Error reading configuration file: {e}" ) from None if not config: return None else: spellcheck_pyproject_toml_keys(ctx, list(config), value) # Sanitize the values to be Click friendly. For more information please see: # https://github.com/psf/black/issues/1458 # https://github.com/pallets/click/issues/1567 config = { k: str(v) if not isinstance(v, (list, dict)) else v for k, v in config.items() } target_version = config.get("target_version") if target_version is not None and not isinstance(target_version, list): raise click.BadOptionUsage( "target-version", "Config key target-version must be a list" ) exclude = config.get("exclude") if exclude is not None and not isinstance(exclude, str): raise click.BadOptionUsage("exclude", "Config key exclude must be a string") extend_exclude = config.get("extend_exclude") if extend_exclude is not None and not isinstance(extend_exclude, str): raise click.BadOptionUsage( "extend-exclude", "Config key extend-exclude must be a string" ) line_ranges = config.get("line_ranges") if line_ranges is not None: raise click.BadOptionUsage( "line-ranges", "Cannot use line-ranges in the pyproject.toml file." ) default_map: dict[str, Any] = {} if ctx.default_map: default_map.update(ctx.default_map) default_map.update(config) ctx.default_map = default_map return value def spellcheck_pyproject_toml_keys( ctx: click.Context, config_keys: list[str], config_file_path: str ) -> None: invalid_keys: list[str] = [] available_config_options = {param.name for param in ctx.command.params} invalid_keys = [key for key in config_keys if key not in available_config_options] if invalid_keys: keys_str = ", ".join(map(repr, invalid_keys)) out( f"Invalid config keys detected: {keys_str} (in {config_file_path})", fg="red", ) def target_version_option_callback( c: click.Context, p: Union[click.Option, click.Parameter], v: tuple[str, ...] ) -> list[TargetVersion]: """Compute the target versions from a --target-version flag. This is its own function because mypy couldn't infer the type correctly when it was a lambda, causing mypyc trouble. """ return [TargetVersion[val.upper()] for val in v] def enable_unstable_feature_callback( c: click.Context, p: Union[click.Option, click.Parameter], v: tuple[str, ...] ) -> list[Preview]: """Compute the features from an --enable-unstable-feature flag.""" return [Preview[val] for val in v] def re_compile_maybe_verbose(regex: str) -> Pattern[str]: """Compile a regular expression string in `regex`. If it contains newlines, use verbose mode. """ if "\n" in regex: regex = "(?x)" + regex compiled: Pattern[str] = re.compile(regex) return compiled def validate_regex( ctx: click.Context, param: click.Parameter, value: Optional[str], ) -> Optional[Pattern[str]]: try: return re_compile_maybe_verbose(value) if value is not None else None except re.error as e: raise click.BadParameter(f"Not a valid regular expression: {e}") from None @click.command( context_settings={"help_option_names": ["-h", "--help"]}, # While Click does set this field automatically using the docstring, mypyc # (annoyingly) strips 'em so we need to set it here too. help="The uncompromising code formatter.", ) @click.option("-c", "--code", type=str, help="Format the code passed in as a string.") @click.option( "-l", "--line-length", type=int, default=DEFAULT_LINE_LENGTH, help="How many characters per line to allow.", show_default=True, ) @click.option( "-t", "--target-version", type=click.Choice([v.name.lower() for v in TargetVersion]), callback=target_version_option_callback, multiple=True, help=( "Python versions that should be supported by Black's output. You should" " include all versions that your code supports. By default, Black will infer" " target versions from the project metadata in pyproject.toml. If this does" " not yield conclusive results, Black will use per-file auto-detection." ), ) @click.option( "--pyi", is_flag=True, help=( "Format all input files like typing stubs regardless of file extension. This" " is useful when piping source on standard input." ), ) @click.option( "--ipynb", is_flag=True, help=( "Format all input files like Jupyter Notebooks regardless of file extension." " This is useful when piping source on standard input." ), ) @click.option( "--python-cell-magics", multiple=True, help=( "When processing Jupyter Notebooks, add the given magic to the list" f" of known python-magics ({', '.join(sorted(PYTHON_CELL_MAGICS))})." " Useful for formatting cells with custom python magics." ), default=[], ) @click.option( "-x", "--skip-source-first-line", is_flag=True, help="Skip the first line of the source code.", ) @click.option( "-S", "--skip-string-normalization", is_flag=True, help="Don't normalize string quotes or prefixes.", ) @click.option( "-C", "--skip-magic-trailing-comma", is_flag=True, help="Don't use trailing commas as a reason to split lines.", ) @click.option( "--preview", is_flag=True, help=( "Enable potentially disruptive style changes that may be added to Black's main" " functionality in the next major release." ), ) @click.option( "--unstable", is_flag=True, help=( "Enable potentially disruptive style changes that have known bugs or are not" " currently expected to make it into the stable style Black's next major" " release. Implies --preview." ), ) @click.option( "--enable-unstable-feature", type=click.Choice([v.name for v in Preview]), callback=enable_unstable_feature_callback, multiple=True, help=( "Enable specific features included in the `--unstable` style. Requires" " `--preview`. No compatibility guarantees are provided on the behavior" " or existence of any unstable features." ), ) @click.option( "--check", is_flag=True, help=( "Don't write the files back, just return the status. Return code 0 means" " nothing would change. Return code 1 means some files would be reformatted." " Return code 123 means there was an internal error." ), ) @click.option( "--diff", is_flag=True, help=( "Don't write the files back, just output a diff to indicate what changes" " Black would've made. They are printed to stdout so capturing them is simple." ), ) @click.option( "--color/--no-color", is_flag=True, help="Show (or do not show) colored diff. Only applies when --diff is given.", ) @click.option( "--line-ranges", multiple=True, metavar="START-END", help=( "When specified, Black will try its best to only format these lines. This" " option can be specified multiple times, and a union of the lines will be" " formatted. Each range must be specified as two integers connected by a `-`:" " `-`. The `` and `` integer indices are 1-based and" " inclusive on both ends." ), default=(), ) @click.option( "--fast/--safe", is_flag=True, help=( "By default, Black performs an AST safety check after formatting your code." " The --fast flag turns off this check and the --safe flag explicitly enables" " it. [default: --safe]" ), ) @click.option( "--required-version", type=str, help=( "Require a specific version of Black to be running. This is useful for" " ensuring that all contributors to your project are using the same" " version, because different versions of Black may format code a little" " differently. This option can be set in a configuration file for consistent" " results across environments." ), ) @click.option( "--exclude", type=str, callback=validate_regex, help=( "A regular expression that matches files and directories that should be" " excluded on recursive searches. An empty value means no paths are excluded." " Use forward slashes for directories on all platforms (Windows, too)." " By default, Black also ignores all paths listed in .gitignore. Changing this" f" value will override all default exclusions. [default: {DEFAULT_EXCLUDES}]" ), show_default=False, ) @click.option( "--extend-exclude", type=str, callback=validate_regex, help=( "Like --exclude, but adds additional files and directories on top of the" " default values instead of overriding them." ), ) @click.option( "--force-exclude", type=str, callback=validate_regex, help=( "Like --exclude, but files and directories matching this regex will be excluded" " even when they are passed explicitly as arguments. This is useful when" " invoking Black programmatically on changed files, such as in a pre-commit" " hook or editor plugin." ), ) @click.option( "--stdin-filename", type=str, is_eager=True, help=( "The name of the file when passing it through stdin. Useful to make sure Black" " will respect the --force-exclude option on some editors that rely on using" " stdin." ), ) @click.option( "--include", type=str, default=DEFAULT_INCLUDES, callback=validate_regex, help=( "A regular expression that matches files and directories that should be" " included on recursive searches. An empty value means all files are included" " regardless of the name. Use forward slashes for directories on all platforms" " (Windows, too). Overrides all exclusions, including from .gitignore and" " command line options." ), show_default=True, ) @click.option( "-W", "--workers", type=click.IntRange(min=1), default=None, help=( "When Black formats multiple files, it may use a process pool to speed up" " formatting. This option controls the number of parallel workers. This can" " also be specified via the BLACK_NUM_WORKERS environment variable. Defaults" " to the number of CPUs in the system." ), ) @click.option( "-q", "--quiet", is_flag=True, help=( "Stop emitting all non-critical output. Error messages will still be emitted" " (which can silenced by 2>/dev/null)." ), ) @click.option( "-v", "--verbose", is_flag=True, help=( "Emit messages about files that were not changed or were ignored due to" " exclusion patterns. If Black is using a configuration file, a message" " detailing which one it is using will be emitted." ), ) @click.version_option( version=__version__, message=( f"%(prog)s, %(version)s (compiled: {'yes' if COMPILED else 'no'})\n" f"Python ({platform.python_implementation()}) {platform.python_version()}" ), ) @click.argument( "src", nargs=-1, type=click.Path( exists=True, file_okay=True, dir_okay=True, readable=True, allow_dash=True ), is_eager=True, metavar="SRC ...", ) @click.option( "--config", type=click.Path( exists=True, file_okay=True, dir_okay=False, readable=True, allow_dash=False, path_type=str, ), is_eager=True, callback=read_pyproject_toml, help="Read configuration options from a configuration file.", ) @click.option( "--no-cache", is_flag=True, help=( "Skip reading and writing the cache, forcing Black to reformat all" " included files." ), ) @click.pass_context def main( # noqa: C901 ctx: click.Context, code: Optional[str], line_length: int, target_version: list[TargetVersion], check: bool, diff: bool, line_ranges: Sequence[str], color: bool, fast: bool, pyi: bool, ipynb: bool, python_cell_magics: Sequence[str], skip_source_first_line: bool, skip_string_normalization: bool, skip_magic_trailing_comma: bool, preview: bool, unstable: bool, enable_unstable_feature: list[Preview], quiet: bool, verbose: bool, required_version: Optional[str], include: Pattern[str], exclude: Optional[Pattern[str]], extend_exclude: Optional[Pattern[str]], force_exclude: Optional[Pattern[str]], stdin_filename: Optional[str], workers: Optional[int], src: tuple[str, ...], config: Optional[str], no_cache: bool, ) -> None: """The uncompromising code formatter.""" ctx.ensure_object(dict) assert sys.version_info >= (3, 9), "Black requires Python 3.9+" if sys.version_info[:3] == (3, 12, 5): out( "Python 3.12.5 has a memory safety issue that can cause Black's " "AST safety checks to fail. " "Please upgrade to Python 3.12.6 or downgrade to Python 3.12.4" ) ctx.exit(1) if src and code is not None: out( main.get_usage(ctx) + "\n\n'SRC' and 'code' cannot be passed simultaneously." ) ctx.exit(1) if not src and code is None: out(main.get_usage(ctx) + "\n\nOne of 'SRC' or 'code' is required.") ctx.exit(1) # It doesn't do anything if --unstable is also passed, so just allow it. if enable_unstable_feature and not (preview or unstable): out( main.get_usage(ctx) + "\n\n'--enable-unstable-feature' requires '--preview'." ) ctx.exit(1) root, method = ( find_project_root(src, stdin_filename) if code is None else (None, None) ) ctx.obj["root"] = root if verbose: if root: out( f"Identified `{root}` as project root containing a {method}.", fg="blue", ) if config: config_source = ctx.get_parameter_source("config") user_level_config = str(find_user_pyproject_toml()) if config == user_level_config: out( "Using configuration from user-level config at " f"'{user_level_config}'.", fg="blue", ) elif config_source in ( ParameterSource.DEFAULT, ParameterSource.DEFAULT_MAP, ): out("Using configuration from project root.", fg="blue") else: out(f"Using configuration in '{config}'.", fg="blue") if ctx.default_map: for param, value in ctx.default_map.items(): out(f"{param}: {value}") error_msg = "Oh no! 💥 💔 💥" if ( required_version and required_version != __version__ and required_version != __version__.split(".")[0] ): err( f"{error_msg} The required version `{required_version}` does not match" f" the running version `{__version__}`!" ) ctx.exit(1) if ipynb and pyi: err("Cannot pass both `pyi` and `ipynb` flags!") ctx.exit(1) write_back = WriteBack.from_configuration(check=check, diff=diff, color=color) if target_version: versions = set(target_version) else: # We'll autodetect later. versions = set() mode = Mode( target_versions=versions, line_length=line_length, is_pyi=pyi, is_ipynb=ipynb, skip_source_first_line=skip_source_first_line, string_normalization=not skip_string_normalization, magic_trailing_comma=not skip_magic_trailing_comma, preview=preview, unstable=unstable, python_cell_magics=set(python_cell_magics), enabled_features=set(enable_unstable_feature), ) lines: list[tuple[int, int]] = [] if line_ranges: if ipynb: err("Cannot use --line-ranges with ipynb files.") ctx.exit(1) try: lines = parse_line_ranges(line_ranges) except ValueError as e: err(str(e)) ctx.exit(1) if code is not None: # Run in quiet mode by default with -c; the extra output isn't useful. # You can still pass -v to get verbose output. quiet = True report = Report(check=check, diff=diff, quiet=quiet, verbose=verbose) if code is not None: reformat_code( content=code, fast=fast, write_back=write_back, mode=mode, report=report, lines=lines, ) else: assert root is not None # root is only None if code is not None try: sources = get_sources( root=root, src=src, quiet=quiet, verbose=verbose, include=include, exclude=exclude, extend_exclude=extend_exclude, force_exclude=force_exclude, report=report, stdin_filename=stdin_filename, ) except GitWildMatchPatternError: ctx.exit(1) if not sources: if verbose or not quiet: out("No Python files are present to be formatted. Nothing to do 😴") if "-" in src: sys.stdout.write(sys.stdin.read()) ctx.exit(0) if len(sources) == 1: reformat_one( src=sources.pop(), fast=fast, write_back=write_back, mode=mode, report=report, lines=lines, no_cache=no_cache, ) else: from black.concurrency import reformat_many if lines: err("Cannot use --line-ranges to format multiple files.") ctx.exit(1) reformat_many( sources=sources, fast=fast, write_back=write_back, mode=mode, report=report, workers=workers, no_cache=no_cache, ) if verbose or not quiet: if code is None and (verbose or report.change_count or report.failure_count): out() out(error_msg if report.return_code else "All done! ✨ 🍰 ✨") if code is None: click.echo(str(report), err=True) ctx.exit(report.return_code) def get_sources( *, root: Path, src: tuple[str, ...], quiet: bool, verbose: bool, include: Pattern[str], exclude: Optional[Pattern[str]], extend_exclude: Optional[Pattern[str]], force_exclude: Optional[Pattern[str]], report: "Report", stdin_filename: Optional[str], ) -> set[Path]: """Compute the set of files to be formatted.""" sources: set[Path] = set() assert root.is_absolute(), f"INTERNAL ERROR: `root` must be absolute but is {root}" using_default_exclude = exclude is None exclude = re_compile_maybe_verbose(DEFAULT_EXCLUDES) if exclude is None else exclude gitignore: Optional[dict[Path, PathSpec]] = None root_gitignore = get_gitignore(root) for s in src: if s == "-" and stdin_filename: path = Path(stdin_filename) if path_is_excluded(stdin_filename, force_exclude): report.path_ignored( path, "--stdin-filename matches the --force-exclude regular expression", ) continue is_stdin = True else: path = Path(s) is_stdin = False # Compare the logic here to the logic in `gen_python_files`. if is_stdin or path.is_file(): if resolves_outside_root_or_cannot_stat(path, root, report): if verbose: out(f'Skipping invalid source: "{path}"', fg="red") continue root_relative_path = best_effort_relative_path(path, root).as_posix() root_relative_path = "/" + root_relative_path # Hard-exclude any files that matches the `--force-exclude` regex. if path_is_excluded(root_relative_path, force_exclude): report.path_ignored( path, "matches the --force-exclude regular expression" ) continue if is_stdin: path = Path(f"{STDIN_PLACEHOLDER}{path}") if path.suffix == ".ipynb" and not jupyter_dependencies_are_installed( warn=verbose or not quiet ): continue if verbose: out(f'Found input source: "{path}"', fg="blue") sources.add(path) elif path.is_dir(): path = root / (path.resolve().relative_to(root)) if verbose: out(f'Found input source directory: "{path}"', fg="blue") if using_default_exclude: gitignore = { root: root_gitignore, path: get_gitignore(path), } sources.update( gen_python_files( path.iterdir(), root, include, exclude, extend_exclude, force_exclude, report, gitignore, verbose=verbose, quiet=quiet, ) ) elif s == "-": if verbose: out("Found input source stdin", fg="blue") sources.add(path) else: err(f"invalid path: {s}") return sources def reformat_code( content: str, fast: bool, write_back: WriteBack, mode: Mode, report: Report, *, lines: Collection[tuple[int, int]] = (), ) -> None: """ Reformat and print out `content` without spawning child processes. Similar to `reformat_one`, but for string content. `fast`, `write_back`, and `mode` options are passed to :func:`format_file_in_place` or :func:`format_stdin_to_stdout`. """ path = Path("") try: changed = Changed.NO if format_stdin_to_stdout( content=content, fast=fast, write_back=write_back, mode=mode, lines=lines ): changed = Changed.YES report.done(path, changed) except Exception as exc: if report.verbose: traceback.print_exc() report.failed(path, str(exc)) # diff-shades depends on being to monkeypatch this function to operate. I know it's # not ideal, but this shouldn't cause any issues ... hopefully. ~ichard26 @mypyc_attr(patchable=True) def reformat_one( src: Path, fast: bool, write_back: WriteBack, mode: Mode, report: "Report", *, lines: Collection[tuple[int, int]] = (), no_cache: bool = False, ) -> None: """Reformat a single file under `src` without spawning child processes. `fast`, `write_back`, and `mode` options are passed to :func:`format_file_in_place` or :func:`format_stdin_to_stdout`. """ try: changed = Changed.NO if str(src) == "-": is_stdin = True elif str(src).startswith(STDIN_PLACEHOLDER): is_stdin = True # Use the original name again in case we want to print something # to the user src = Path(str(src)[len(STDIN_PLACEHOLDER) :]) else: is_stdin = False if is_stdin: if src.suffix == ".pyi": mode = replace(mode, is_pyi=True) elif src.suffix == ".ipynb": mode = replace(mode, is_ipynb=True) if format_stdin_to_stdout( fast=fast, write_back=write_back, mode=mode, lines=lines ): changed = Changed.YES else: cache = None if no_cache else Cache.read(mode) if cache is not None and write_back not in ( WriteBack.DIFF, WriteBack.COLOR_DIFF, ): if not cache.is_changed(src): changed = Changed.CACHED if changed is not Changed.CACHED and format_file_in_place( src, fast=fast, write_back=write_back, mode=mode, lines=lines ): changed = Changed.YES if cache is not None and ( (write_back is WriteBack.YES and changed is not Changed.CACHED) or (write_back is WriteBack.CHECK and changed is Changed.NO) ): cache.write([src]) report.done(src, changed) except Exception as exc: if report.verbose: traceback.print_exc() report.failed(src, str(exc)) def format_file_in_place( src: Path, fast: bool, mode: Mode, write_back: WriteBack = WriteBack.NO, lock: Any = None, # multiprocessing.Manager().Lock() is some crazy proxy *, lines: Collection[tuple[int, int]] = (), ) -> bool: """Format file under `src` path. Return True if changed. If `write_back` is DIFF, write a diff to stdout. If it is YES, write reformatted code to the file. `mode` and `fast` options are passed to :func:`format_file_contents`. """ if src.suffix == ".pyi": mode = replace(mode, is_pyi=True) elif src.suffix == ".ipynb": mode = replace(mode, is_ipynb=True) then = datetime.fromtimestamp(src.stat().st_mtime, timezone.utc) header = b"" with open(src, "rb") as buf: if mode.skip_source_first_line: header = buf.readline() src_contents, encoding, newline = decode_bytes(buf.read(), mode) try: dst_contents = format_file_contents( src_contents, fast=fast, mode=mode, lines=lines ) except NothingChanged: return False except JSONDecodeError: raise ValueError( f"File '{src}' cannot be parsed as valid Jupyter notebook." ) from None src_contents = header.decode(encoding) + src_contents dst_contents = header.decode(encoding) + dst_contents if write_back == WriteBack.YES: with open(src, "w", encoding=encoding, newline=newline) as f: f.write(dst_contents) elif write_back in (WriteBack.DIFF, WriteBack.COLOR_DIFF): now = datetime.now(timezone.utc) src_name = f"{src}\t{then}" dst_name = f"{src}\t{now}" if mode.is_ipynb: diff_contents = ipynb_diff(src_contents, dst_contents, src_name, dst_name) else: diff_contents = diff(src_contents, dst_contents, src_name, dst_name) if write_back == WriteBack.COLOR_DIFF: diff_contents = color_diff(diff_contents) with lock or nullcontext(): f = io.TextIOWrapper( sys.stdout.buffer, encoding=encoding, newline=newline, write_through=True, ) f = wrap_stream_for_windows(f) f.write(diff_contents) f.detach() return True def format_stdin_to_stdout( fast: bool, *, content: Optional[str] = None, write_back: WriteBack = WriteBack.NO, mode: Mode, lines: Collection[tuple[int, int]] = (), ) -> bool: """Format file on stdin. Return True if changed. If content is None, it's read from sys.stdin. If `write_back` is YES, write reformatted code back to stdout. If it is DIFF, write a diff to stdout. The `mode` argument is passed to :func:`format_file_contents`. """ then = datetime.now(timezone.utc) if content is None: src, encoding, newline = decode_bytes(sys.stdin.buffer.read(), mode) elif Preview.normalize_cr_newlines in mode: src, encoding, newline = content, "utf-8", "\n" else: src, encoding, newline = content, "utf-8", "" dst = src try: dst = format_file_contents(src, fast=fast, mode=mode, lines=lines) return True except NothingChanged: return False finally: f = io.TextIOWrapper( sys.stdout.buffer, encoding=encoding, newline=newline, write_through=True ) if write_back == WriteBack.YES: # Make sure there's a newline after the content if Preview.normalize_cr_newlines in mode: if dst and dst[-1] != "\n" and dst[-1] != "\r": dst += newline else: if dst and dst[-1] != "\n": dst += "\n" f.write(dst) elif write_back in (WriteBack.DIFF, WriteBack.COLOR_DIFF): now = datetime.now(timezone.utc) src_name = f"STDIN\t{then}" dst_name = f"STDOUT\t{now}" d = diff(src, dst, src_name, dst_name) if write_back == WriteBack.COLOR_DIFF: d = color_diff(d) f = wrap_stream_for_windows(f) f.write(d) f.detach() def check_stability_and_equivalence( src_contents: str, dst_contents: str, *, mode: Mode, lines: Collection[tuple[int, int]] = (), ) -> None: """Perform stability and equivalence checks. Raise AssertionError if source and destination contents are not equivalent, or if a second pass of the formatter would format the content differently. """ assert_equivalent(src_contents, dst_contents) assert_stable(src_contents, dst_contents, mode=mode, lines=lines) def format_file_contents( src_contents: str, *, fast: bool, mode: Mode, lines: Collection[tuple[int, int]] = (), ) -> FileContent: """Reformat contents of a file and return new contents. If `fast` is False, additionally confirm that the reformatted code is valid by calling :func:`assert_equivalent` and :func:`assert_stable` on it. `mode` is passed to :func:`format_str`. """ if mode.is_ipynb: dst_contents = format_ipynb_string(src_contents, fast=fast, mode=mode) else: dst_contents = format_str(src_contents, mode=mode, lines=lines) if src_contents == dst_contents: raise NothingChanged if not fast and not mode.is_ipynb: # Jupyter notebooks will already have been checked above. check_stability_and_equivalence( src_contents, dst_contents, mode=mode, lines=lines ) return dst_contents def format_cell(src: str, *, fast: bool, mode: Mode) -> str: """Format code in given cell of Jupyter notebook. General idea is: - if cell has trailing semicolon, remove it; - if cell has IPython magics, mask them; - format cell; - reinstate IPython magics; - reinstate trailing semicolon (if originally present); - strip trailing newlines. Cells with syntax errors will not be processed, as they could potentially be automagics or multi-line magics, which are currently not supported. """ validate_cell(src, mode) src_without_trailing_semicolon, has_trailing_semicolon = remove_trailing_semicolon( src ) try: masked_src, replacements = mask_cell(src_without_trailing_semicolon) except SyntaxError: raise NothingChanged from None masked_dst = format_str(masked_src, mode=mode) if not fast: check_stability_and_equivalence(masked_src, masked_dst, mode=mode) dst_without_trailing_semicolon = unmask_cell(masked_dst, replacements) dst = put_trailing_semicolon_back( dst_without_trailing_semicolon, has_trailing_semicolon ) dst = dst.rstrip("\n") if dst == src: raise NothingChanged from None return dst def validate_metadata(nb: MutableMapping[str, Any]) -> None: """If notebook is marked as non-Python, don't format it. All notebook metadata fields are optional, see https://nbformat.readthedocs.io/en/latest/format_description.html. So if a notebook has empty metadata, we will try to parse it anyway. """ language = nb.get("metadata", {}).get("language_info", {}).get("name", None) if language is not None and language != "python": raise NothingChanged from None def format_ipynb_string(src_contents: str, *, fast: bool, mode: Mode) -> FileContent: """Format Jupyter notebook. Operate cell-by-cell, only on code cells, only for Python notebooks. If the ``.ipynb`` originally had a trailing newline, it'll be preserved. """ if not src_contents: raise NothingChanged trailing_newline = src_contents[-1] == "\n" modified = False nb = json.loads(src_contents) validate_metadata(nb) for cell in nb["cells"]: if cell.get("cell_type", None) == "code": try: src = "".join(cell["source"]) dst = format_cell(src, fast=fast, mode=mode) except NothingChanged: pass else: cell["source"] = dst.splitlines(keepends=True) modified = True if modified: dst_contents = json.dumps(nb, indent=1, ensure_ascii=False) if trailing_newline: dst_contents = dst_contents + "\n" return dst_contents else: raise NothingChanged def format_str( src_contents: str, *, mode: Mode, lines: Collection[tuple[int, int]] = () ) -> str: """Reformat a string and return new contents. `mode` determines formatting options, such as how many characters per line are allowed. Example: >>> import black >>> print(black.format_str("def f(arg:str='')->None:...", mode=black.Mode())) def f(arg: str = "") -> None: ... A more complex example: >>> print( ... black.format_str( ... "def f(arg:str='')->None: hey", ... mode=black.Mode( ... target_versions={black.TargetVersion.PY36}, ... line_length=10, ... string_normalization=False, ... is_pyi=False, ... ), ... ), ... ) def f( arg: str = '', ) -> None: hey """ if lines: lines = sanitized_lines(lines, src_contents) if not lines: return src_contents # Nothing to format dst_contents = _format_str_once(src_contents, mode=mode, lines=lines) # Forced second pass to work around optional trailing commas (becoming # forced trailing commas on pass 2) interacting differently with optional # parentheses. Admittedly ugly. if src_contents != dst_contents: if lines: lines = adjusted_lines(lines, src_contents, dst_contents) return _format_str_once(dst_contents, mode=mode, lines=lines) return dst_contents def _format_str_once( src_contents: str, *, mode: Mode, lines: Collection[tuple[int, int]] = () ) -> str: if Preview.normalize_cr_newlines in mode: normalized_contents, _, newline_type = decode_bytes( src_contents.encode("utf-8"), mode ) src_node = lib2to3_parse( normalized_contents.lstrip(), target_versions=mode.target_versions ) else: src_node = lib2to3_parse(src_contents.lstrip(), mode.target_versions) dst_blocks: list[LinesBlock] = [] if mode.target_versions: versions = mode.target_versions else: future_imports = get_future_imports(src_node) versions = detect_target_versions(src_node, future_imports=future_imports) line_generation_features = { feature for feature in { Feature.PARENTHESIZED_CONTEXT_MANAGERS, Feature.UNPARENTHESIZED_EXCEPT_TYPES, Feature.T_STRINGS, } if supports_feature(versions, feature) } normalize_fmt_off(src_node, mode, lines) if lines: # This should be called after normalize_fmt_off. convert_unchanged_lines(src_node, lines) line_generator = LineGenerator(mode=mode, features=line_generation_features) elt = EmptyLineTracker(mode=mode) split_line_features = { feature for feature in { Feature.TRAILING_COMMA_IN_CALL, Feature.TRAILING_COMMA_IN_DEF, } if supports_feature(versions, feature) } block: Optional[LinesBlock] = None for current_line in line_generator.visit(src_node): block = elt.maybe_empty_lines(current_line) dst_blocks.append(block) for line in transform_line( current_line, mode=mode, features=split_line_features ): block.content_lines.append(str(line)) if dst_blocks: dst_blocks[-1].after = 0 dst_contents = [] for block in dst_blocks: dst_contents.extend(block.all_lines()) if not dst_contents: if Preview.normalize_cr_newlines in mode: if "\n" in normalized_contents: return newline_type else: # Use decode_bytes to retrieve the correct source newline (CRLF or LF), # and check if normalized_content has more than one line normalized_content, _, newline = decode_bytes( src_contents.encode("utf-8"), mode ) if "\n" in normalized_content: return newline return "" if Preview.normalize_cr_newlines in mode: return "".join(dst_contents).replace("\n", newline_type) else: return "".join(dst_contents) def decode_bytes(src: bytes, mode: Mode) -> tuple[FileContent, Encoding, NewLine]: """Return a tuple of (decoded_contents, encoding, newline). `newline` is either CRLF or LF but `decoded_contents` is decoded with universal newlines (i.e. only contains LF). """ srcbuf = io.BytesIO(src) encoding, lines = tokenize.detect_encoding(srcbuf.readline) if not lines: return "", encoding, "\n" if Preview.normalize_cr_newlines in mode: if lines[0][-2:] == b"\r\n": if b"\r" in lines[0][:-2]: newline = "\r" else: newline = "\r\n" elif lines[0][-1:] == b"\n": if b"\r" in lines[0][:-1]: newline = "\r" else: newline = "\n" else: if b"\r" in lines[0]: newline = "\r" else: newline = "\n" else: newline = "\r\n" if lines[0][-2:] == b"\r\n" else "\n" srcbuf.seek(0) with io.TextIOWrapper(srcbuf, encoding) as tiow: return tiow.read(), encoding, newline def get_features_used( # noqa: C901 node: Node, *, future_imports: Optional[set[str]] = None ) -> set[Feature]: """Return a set of (relatively) new Python features used in this file. Currently looking for: - f-strings; - self-documenting expressions in f-strings (f"{x=}"); - underscores in numeric literals; - trailing commas after * or ** in function signatures and calls; - positional only arguments in function signatures and lambdas; - assignment expression; - relaxed decorator syntax; - usage of __future__ flags (annotations); - print / exec statements; - parenthesized context managers; - match statements; - except* clause; - variadic generics; """ features: set[Feature] = set() if future_imports: features |= { FUTURE_FLAG_TO_FEATURE[future_import] for future_import in future_imports if future_import in FUTURE_FLAG_TO_FEATURE } for n in node.pre_order(): if n.type == token.FSTRING_START: features.add(Feature.F_STRINGS) elif n.type == token.TSTRING_START: features.add(Feature.T_STRINGS) elif ( n.type == token.RBRACE and n.parent is not None and any(child.type == token.EQUAL for child in n.parent.children) ): features.add(Feature.DEBUG_F_STRINGS) elif is_number_token(n): if "_" in n.value: features.add(Feature.NUMERIC_UNDERSCORES) elif n.type == token.SLASH: if n.parent and n.parent.type in { syms.typedargslist, syms.arglist, syms.varargslist, }: features.add(Feature.POS_ONLY_ARGUMENTS) elif n.type == token.COLONEQUAL: features.add(Feature.ASSIGNMENT_EXPRESSIONS) elif n.type == syms.decorator: if len(n.children) > 1 and not is_simple_decorator_expression( n.children[1] ): features.add(Feature.RELAXED_DECORATORS) elif ( n.type in {syms.typedargslist, syms.arglist} and n.children and n.children[-1].type == token.COMMA ): if n.type == syms.typedargslist: feature = Feature.TRAILING_COMMA_IN_DEF else: feature = Feature.TRAILING_COMMA_IN_CALL for ch in n.children: if ch.type in STARS: features.add(feature) if ch.type == syms.argument: for argch in ch.children: if argch.type in STARS: features.add(feature) elif ( n.type in {syms.return_stmt, syms.yield_expr} and len(n.children) >= 2 and n.children[1].type == syms.testlist_star_expr and any(child.type == syms.star_expr for child in n.children[1].children) ): features.add(Feature.UNPACKING_ON_FLOW) elif ( n.type == syms.annassign and len(n.children) >= 4 and n.children[3].type == syms.testlist_star_expr ): features.add(Feature.ANN_ASSIGN_EXTENDED_RHS) elif ( n.type == syms.with_stmt and len(n.children) > 2 and n.children[1].type == syms.atom ): atom_children = n.children[1].children if ( len(atom_children) == 3 and atom_children[0].type == token.LPAR and _contains_asexpr(atom_children[1]) and atom_children[2].type == token.RPAR ): features.add(Feature.PARENTHESIZED_CONTEXT_MANAGERS) elif n.type == syms.match_stmt: features.add(Feature.PATTERN_MATCHING) elif n.type in {syms.subscriptlist, syms.trailer} and any( child.type == syms.star_expr for child in n.children ): features.add(Feature.VARIADIC_GENERICS) elif ( n.type == syms.tname_star and len(n.children) == 3 and n.children[2].type == syms.star_expr ): features.add(Feature.VARIADIC_GENERICS) elif n.type in (syms.type_stmt, syms.typeparams): features.add(Feature.TYPE_PARAMS) elif ( n.type in (syms.typevartuple, syms.paramspec, syms.typevar) and n.children[-2].type == token.EQUAL ): features.add(Feature.TYPE_PARAM_DEFAULTS) elif ( n.type == syms.except_clause and len(n.children) >= 2 and ( n.children[1].type == token.STAR or n.children[1].type == syms.testlist ) ): is_star_except = n.children[1].type == token.STAR if is_star_except: features.add(Feature.EXCEPT_STAR) # Presence of except* pushes as clause 1 index back has_as_clause = ( len(n.children) >= is_star_except + 3 and n.children[is_star_except + 2].type == token.NAME and n.children[is_star_except + 2].value == "as" # type: ignore ) # If there's no 'as' clause and the except expression is a testlist. if not has_as_clause and ( (is_star_except and n.children[2].type == syms.testlist) or (not is_star_except and n.children[1].type == syms.testlist) ): features.add(Feature.UNPARENTHESIZED_EXCEPT_TYPES) return features def _contains_asexpr(node: Union[Node, Leaf]) -> bool: """Return True if `node` contains an as-pattern.""" if node.type == syms.asexpr_test: return True elif node.type == syms.atom: if ( len(node.children) == 3 and node.children[0].type == token.LPAR and node.children[2].type == token.RPAR ): return _contains_asexpr(node.children[1]) elif node.type == syms.testlist_gexp: return any(_contains_asexpr(child) for child in node.children) return False def detect_target_versions( node: Node, *, future_imports: Optional[set[str]] = None ) -> set[TargetVersion]: """Detect the version to target based on the nodes used.""" features = get_features_used(node, future_imports=future_imports) return { version for version in TargetVersion if features <= VERSION_TO_FEATURES[version] } def get_future_imports(node: Node) -> set[str]: """Return a set of __future__ imports in the file.""" imports: set[str] = set() def get_imports_from_children(children: list[LN]) -> Generator[str, None, None]: for child in children: if isinstance(child, Leaf): if child.type == token.NAME: yield child.value elif child.type == syms.import_as_name: orig_name = child.children[0] assert isinstance(orig_name, Leaf), "Invalid syntax parsing imports" assert orig_name.type == token.NAME, "Invalid syntax parsing imports" yield orig_name.value elif child.type == syms.import_as_names: yield from get_imports_from_children(child.children) else: raise AssertionError("Invalid syntax parsing imports") for child in node.children: if child.type != syms.simple_stmt: break first_child = child.children[0] if isinstance(first_child, Leaf): # Continue looking if we see a docstring; otherwise stop. if ( len(child.children) == 2 and first_child.type == token.STRING and child.children[1].type == token.NEWLINE ): continue break elif first_child.type == syms.import_from: module_name = first_child.children[1] if not isinstance(module_name, Leaf) or module_name.value != "__future__": break imports |= set(get_imports_from_children(first_child.children[3:])) else: break return imports def _black_info() -> str: return ( f"Black {__version__} on " f"Python ({platform.python_implementation()}) {platform.python_version()}" ) def assert_equivalent(src: str, dst: str) -> None: """Raise AssertionError if `src` and `dst` aren't equivalent.""" try: src_ast = parse_ast(src) except Exception as exc: raise ASTSafetyError( "cannot use --safe with this file; failed to parse source file AST: " f"{exc}\n" "This could be caused by running Black with an older Python version " "that does not support new syntax used in your source file." ) from exc try: dst_ast = parse_ast(dst) except Exception as exc: log = dump_to_file("".join(traceback.format_tb(exc.__traceback__)), dst) raise ASTSafetyError( f"INTERNAL ERROR: {_black_info()} produced invalid code: {exc}. " "Please report a bug on https://github.com/psf/black/issues. " f"This invalid output might be helpful: {log}" ) from None src_ast_str = "\n".join(stringify_ast(src_ast)) dst_ast_str = "\n".join(stringify_ast(dst_ast)) if src_ast_str != dst_ast_str: log = dump_to_file(diff(src_ast_str, dst_ast_str, "src", "dst")) raise ASTSafetyError( f"INTERNAL ERROR: {_black_info()} produced code that is not equivalent to" " the source. Please report a bug on https://github.com/psf/black/issues." f" This diff might be helpful: {log}" ) from None def assert_stable( src: str, dst: str, mode: Mode, *, lines: Collection[tuple[int, int]] = () ) -> None: """Raise AssertionError if `dst` reformats differently the second time.""" if lines: # Formatting specified lines requires `adjusted_lines` to map original lines # to the formatted lines before re-formatting the previously formatted result. # Due to less-ideal diff algorithm, some edge cases produce incorrect new line # ranges. Hence for now, we skip the stable check. # See https://github.com/psf/black/issues/4033 for context. return # We shouldn't call format_str() here, because that formats the string # twice and may hide a bug where we bounce back and forth between two # versions. newdst = _format_str_once(dst, mode=mode, lines=lines) if dst != newdst: log = dump_to_file( str(mode), diff(src, dst, "source", "first pass"), diff(dst, newdst, "first pass", "second pass"), ) raise AssertionError( f"INTERNAL ERROR: {_black_info()} produced different code on the second" " pass of the formatter. Please report a bug on" f" https://github.com/psf/black/issues. This diff might be helpful: {log}" ) from None @contextmanager def nullcontext() -> Iterator[None]: """Return an empty context manager. To be used like `nullcontext` in Python 3.7. """ yield def patched_main() -> None: # PyInstaller patches multiprocessing to need freeze_support() even in non-Windows # environments so just assume we always need to call it if frozen. if getattr(sys, "frozen", False): from multiprocessing import freeze_support freeze_support() main() if __name__ == "__main__": patched_main()