X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/c5fd578279ce9c576f5a5c9b56e5580a14227997..44a235173119eb63b27a648b931940f13c04f424:/black.py diff --git a/black.py b/black.py index 9ea4694..434bc33 100644 --- a/black.py +++ b/black.py @@ -38,18 +38,19 @@ err = partial(click.secho, fg='red', err=True) class NothingChanged(UserWarning): - """Raised by `format_file` when the reformatted code is the same as source.""" + """Raised by :func:`format_file` when reformatted code is the same as source.""" class CannotSplit(Exception): """A readable split that fits the allotted line length is impossible. - Raised by `left_hand_split()`, `right_hand_split()`, and `delimiter_split()`. + Raised by :func:`left_hand_split`, :func:`right_hand_split`, and + :func:`delimiter_split`. """ class FormatError(Exception): - """Base fmt: on/off error. + """Base exception for `# fmt: on` and `# fmt: off` handling. It holds the number of bytes of the prefix consumed before the format control comment appeared. @@ -165,6 +166,13 @@ async def schedule_formatting( loop: BaseEventLoop, executor: Executor, ) -> int: + """Run formatting of `sources` in parallel using the provided `executor`. + + (Use ProcessPoolExecutors for actual parallelism.) + + `line_length`, `write_back`, and `fast` options are passed to + :func:`format_file_in_place`. + """ tasks = { src: loop.run_in_executor( executor, format_file_in_place, src, line_length, fast, write_back @@ -193,7 +201,11 @@ async def schedule_formatting( def format_file_in_place( src: Path, line_length: int, fast: bool, write_back: bool = False ) -> bool: - """Format the file and rewrite if changed. Return True if changed.""" + """Format file under `src` path. Return True if changed. + + If `write_back` is True, write reformatted code back to stdout. + `line_length` and `fast` options are passed to :func:`format_file_contents`. + """ with tokenize.open(src) as src_buffer: src_contents = src_buffer.read() try: @@ -212,7 +224,11 @@ def format_file_in_place( def format_stdin_to_stdout( line_length: int, fast: bool, write_back: bool = False ) -> bool: - """Format file on stdin and pipe output to stdout. Return True if changed.""" + """Format file on stdin. Return True if changed. + + If `write_back` is True, write reformatted code back to stdout. + `line_length` and `fast` arguments are passed to :func:`format_file_contents`. + """ contents = sys.stdin.read() try: contents = format_file_contents(contents, line_length=line_length, fast=fast) @@ -229,7 +245,12 @@ def format_stdin_to_stdout( def format_file_contents( src_contents: str, line_length: int, fast: bool ) -> FileContent: - """Reformats a file and returns its contents and encoding.""" + """Reformat contents 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. + `line_length` is passed to :func:`format_str`. + """ if src_contents.strip() == '': raise NothingChanged @@ -244,7 +265,10 @@ def format_file_contents( def format_str(src_contents: str, line_length: int) -> FileContent: - """Reformats a string and returns new contents.""" + """Reformat a string and return new contents. + + `line_length` determines how many characters per line are allowed. + """ src_node = lib2to3_parse(src_contents) dst_contents = "" lines = LineGenerator() @@ -309,9 +333,18 @@ T = TypeVar('T') class Visitor(Generic[T]): - """Basic lib2to3 visitor that yields things on visiting.""" + """Basic lib2to3 visitor that yields things of type `T` on `visit()`.""" def visit(self, node: LN) -> Iterator[T]: + """Main method to visit `node` and its children. + + It tries to find a `visit_*()` method for the given `node.type`, like + `visit_simple_stmt` for Node objects or `visit_INDENT` for Leaf objects. + If no dedicated `visit_*()` method is found, chooses `visit_default()` + instead. + + Then yields objects of type `T` from the selected visitor. + """ if node.type < 256: name = token.tok_name[node.type] else: @@ -319,6 +352,7 @@ class Visitor(Generic[T]): yield from getattr(self, f'visit_{name}', self.visit_default)(node) def visit_default(self, node: LN) -> Iterator[T]: + """Default `visit_*()` implementation. Recurses to children of `node`.""" if isinstance(node, Node): for child in node.children: yield from self.visit(child) @@ -350,7 +384,7 @@ class DebugVisitor(Visitor[T]): @classmethod def show(cls, code: str) -> None: - """Pretty-prints a given string of `code`. + """Pretty-print the lib2to3 AST of a given string of `code`. Convenience method for debugging. """ @@ -406,12 +440,28 @@ MATH_PRIORITY = 1 @dataclass class BracketTracker: + """Keeps track of brackets on a line.""" + depth: int = 0 bracket_match: Dict[Tuple[Depth, NodeType], Leaf] = Factory(dict) delimiters: Dict[LeafID, Priority] = Factory(dict) previous: Optional[Leaf] = None def mark(self, leaf: Leaf) -> None: + """Mark `leaf` with bracket-related metadata. Keep track of delimiters. + + All leaves receive an int `bracket_depth` field that stores how deep + within brackets a given leaf is. 0 means there are no enclosing brackets + that started on this line. + + If a leaf is itself a closing bracket, it receives an `opening_bracket` + field that it forms a pair with. This is a one-directional link to + avoid reference cycles. + + If a leaf is a delimiter (a token on which Black can split the line if + needed) and it's on depth 0, its `id()` is stored in the tracker's + `delimiters` field. + """ if leaf.type == token.COMMENT: return @@ -453,11 +503,11 @@ class BracketTracker: self.previous = leaf def any_open_brackets(self) -> bool: - """Returns True if there is an yet unmatched open bracket on the line.""" + """Return True if there is an yet unmatched open bracket on the line.""" return bool(self.bracket_match) - def max_priority(self, exclude: Iterable[LeafID] = ()) -> int: - """Returns the highest priority of a delimiter found on the line. + def max_delimiter_priority(self, exclude: Iterable[LeafID] = ()) -> int: + """Return the highest priority of a delimiter found on the line. Values are consistent with what `is_delimiter()` returns. """ @@ -466,6 +516,8 @@ class BracketTracker: @dataclass class Line: + """Holds leaves and comments. Can be printed with `str(line)`.""" + depth: int = 0 leaves: List[Leaf] = Factory(list) comments: Dict[LeafID, Leaf] = Factory(dict) @@ -475,6 +527,15 @@ class Line: _for_loop_variable: bool = False def append(self, leaf: Leaf, preformatted: bool = False) -> None: + """Add a new `leaf` to the end of the line. + + Unless `preformatted` is True, the `leaf` will receive a new consistent + whitespace prefix and metadata applied by :class:`BracketTracker`. + Trailing commas are maybe removed, unpacked for loop variables are + demoted from being delimiters. + + Inline comments are put aside. + """ has_value = leaf.value.strip() if not has_value: return @@ -496,18 +557,22 @@ class Line: @property def is_comment(self) -> bool: + """Is this line a standalone comment?""" return bool(self) and self.leaves[0].type == STANDALONE_COMMENT @property def is_decorator(self) -> bool: + """Is this line a decorator?""" return bool(self) and self.leaves[0].type == token.AT @property def is_import(self) -> bool: + """Is this an import line?""" return bool(self) and is_import(self.leaves[0]) @property def is_class(self) -> bool: + """Is this line a class definition?""" return ( bool(self) and self.leaves[0].type == token.NAME @@ -516,7 +581,7 @@ class Line: @property def is_def(self) -> bool: - """Also returns True for async defs.""" + """Is this a function definition? (Also returns True for async defs.)""" try: first_leaf = self.leaves[0] except IndexError: @@ -538,6 +603,10 @@ class Line: @property def is_flow_control(self) -> bool: + """Is this line a flow control statement? + + Those are `return`, `raise`, `break`, and `continue`. + """ return ( bool(self) and self.leaves[0].type == token.NAME @@ -546,6 +615,7 @@ class Line: @property def is_yield(self) -> bool: + """Is this line a yield statement?""" return ( bool(self) and self.leaves[0].type == token.NAME @@ -553,6 +623,7 @@ class Line: ) def maybe_remove_trailing_comma(self, closing: Leaf) -> bool: + """Remove trailing comma if there is one and it's safe.""" if not ( self.leaves and self.leaves[-1].type == token.COMMA @@ -603,8 +674,8 @@ class Line: def maybe_increment_for_loop_variable(self, leaf: Leaf) -> bool: """In a for loop, or comprehension, the variables are often unpacks. - To avoid splitting on the comma in this situation, we will increase - the depth of tokens between `for` and `in`. + To avoid splitting on the comma in this situation, increase the depth of + tokens between `for` and `in`. """ if leaf.type == token.NAME and leaf.value == 'for': self.has_for = True @@ -615,7 +686,7 @@ class Line: return False def maybe_decrement_after_for_loop_variable(self, leaf: Leaf) -> bool: - # See `maybe_increment_for_loop_variable` above for explanation. + """See `maybe_increment_for_loop_variable` above for explanation.""" if self._for_loop_variable and leaf.type == token.NAME and leaf.value == 'in': self.bracket_tracker.depth -= 1 self._for_loop_variable = False @@ -643,6 +714,7 @@ class Line: return self.append_comment(comment) def append_comment(self, comment: Leaf) -> bool: + """Add an inline comment to the line.""" if comment.type != token.COMMENT: return False @@ -661,6 +733,7 @@ class Line: return True def last_non_delimiter(self) -> Leaf: + """Return the last non-delimiter on the line. Raise LookupError otherwise.""" for i in range(len(self.leaves)): last = self.leaves[-i - 1] if not is_delimiter(last): @@ -669,6 +742,7 @@ class Line: raise LookupError("No non-delimiters found") def __str__(self) -> str: + """Render the line.""" if not self: return '\n' @@ -683,12 +757,21 @@ class Line: return res + '\n' def __bool__(self) -> bool: + """Return True if the line has leaves or comments.""" return bool(self.leaves or self.comments) class UnformattedLines(Line): + """Just like :class:`Line` but stores lines which aren't reformatted.""" - def append(self, leaf: Leaf, preformatted: bool = False) -> None: + def append(self, leaf: Leaf, preformatted: bool = True) -> None: + """Just add a new `leaf` to the end of the lines. + + The `preformatted` argument is ignored. + + Keeps track of indentation `depth`, which is useful when the user + says `# fmt: on`. Otherwise, doesn't do anything with the `leaf`. + """ try: list(generate_comments(leaf)) except FormatOn as f_on: @@ -701,27 +784,35 @@ class UnformattedLines(Line): elif leaf.type == token.DEDENT: self.depth -= 1 + def __str__(self) -> str: + """Render unformatted lines from leaves which were added with `append()`. + + `depth` is not used for indentation in this case. + """ + if not self: + return '\n' + + res = '' + for leaf in self.leaves: + res += str(leaf) + return res + def append_comment(self, comment: Leaf) -> bool: + """Not implemented in this class. Raises `NotImplementedError`.""" raise NotImplementedError("Unformatted lines don't store comments separately.") def maybe_remove_trailing_comma(self, closing: Leaf) -> bool: + """Does nothing and returns False.""" return False def maybe_increment_for_loop_variable(self, leaf: Leaf) -> bool: + """Does nothing and returns False.""" return False def maybe_adapt_standalone_comment(self, comment: Leaf) -> bool: + """Does nothing and returns False.""" return False - def __str__(self) -> str: - if not self: - return '\n' - - res = '' - for leaf in self.leaves: - res += str(leaf) - return res - @dataclass class EmptyLineTracker: @@ -737,11 +828,11 @@ class EmptyLineTracker: previous_defs: List[int] = Factory(list) def maybe_empty_lines(self, current_line: Line) -> Tuple[int, int]: - """Returns the number of extra empty lines before and after the `current_line`. + """Return the number of extra empty lines before and after the `current_line`. - This is for separating `def`, `async def` and `class` with extra empty lines - (two on module-level), as well as providing an extra empty line after flow - control keywords to make them more prominent. + This is for separating `def`, `async def` and `class` with extra empty + lines (two on module-level), as well as providing an extra empty line + after flow control keywords to make them more prominent. """ if isinstance(current_line, UnformattedLines): return 0, 0 @@ -754,13 +845,13 @@ class EmptyLineTracker: def _maybe_empty_lines(self, current_line: Line) -> Tuple[int, int]: max_allowed = 1 - if current_line.is_comment and current_line.depth == 0: + if current_line.depth == 0: max_allowed = 2 if current_line.leaves: # Consume the first leaf's extra newlines. first_leaf = current_line.leaves[0] before = first_leaf.prefix.count('\n') - before = min(before, max(before, max_allowed)) + before = min(before, max_allowed) first_leaf.prefix = '' else: before = 0 @@ -835,7 +926,10 @@ class LineGenerator(Visitor[Line]): yield complete_line def visit(self, node: LN) -> Iterator[Line]: - """High-level entry point to the visitor.""" + """Main method to visit `node` and its children. + + Yields :class:`Line` objects. + """ if isinstance(self.current_line, UnformattedLines): # File contained `# fmt: off` yield from self.visit_unformatted(node) @@ -844,6 +938,7 @@ class LineGenerator(Visitor[Line]): yield from super().visit(node) def visit_default(self, node: LN) -> Iterator[Line]: + """Default `visit_*()` implementation. Recurses to children of `node`.""" if isinstance(node, Leaf): any_open_brackets = self.current_line.bracket_tracker.any_open_brackets() try: @@ -881,18 +976,24 @@ class LineGenerator(Visitor[Line]): yield from super().visit_default(node) def visit_INDENT(self, node: Node) -> Iterator[Line]: + """Increase indentation level, maybe yield a line.""" + # In blib2to3 INDENT never holds comments. yield from self.line(+1) yield from self.visit_default(node) def visit_DEDENT(self, node: Node) -> Iterator[Line]: + """Decrease indentation level, maybe yield a line.""" # DEDENT has no value. Additionally, in blib2to3 it never holds comments. yield from self.line(-1) def visit_stmt(self, node: Node, keywords: Set[str]) -> Iterator[Line]: """Visit a statement. - The relevant Python language keywords for this statement are NAME leaves - within it. + This implementation is shared for `if`, `while`, `for`, `try`, `except`, + `def`, `with`, and `class`. + + The relevant Python language `keywords` for a given statement will be NAME + leaves within it. This methods puts those on a separate line. """ for child in node.children: if child.type == token.NAME and child.value in keywords: # type: ignore @@ -901,7 +1002,7 @@ class LineGenerator(Visitor[Line]): yield from self.visit(child) def visit_simple_stmt(self, node: Node) -> Iterator[Line]: - """A statement without nested statements.""" + """Visit a statement without nested statements.""" is_suite_like = node.parent and node.parent.type in STATEMENT if is_suite_like: yield from self.line(+1) @@ -913,6 +1014,7 @@ class LineGenerator(Visitor[Line]): yield from self.visit_default(node) def visit_async_stmt(self, node: Node) -> Iterator[Line]: + """Visit `async def`, `async for`, `async with`.""" yield from self.line() children = iter(node.children) @@ -927,18 +1029,22 @@ class LineGenerator(Visitor[Line]): yield from self.visit(child) def visit_decorators(self, node: Node) -> Iterator[Line]: + """Visit decorators.""" for child in node.children: yield from self.line() yield from self.visit(child) def visit_SEMI(self, leaf: Leaf) -> Iterator[Line]: + """Remove a semicolon and put the other statement on a separate line.""" yield from self.line() def visit_ENDMARKER(self, leaf: Leaf) -> Iterator[Line]: + """End of file. Process outstanding comments and end with a newline.""" yield from self.visit_default(leaf) yield from self.line() def visit_unformatted(self, node: LN) -> Iterator[Line]: + """Used when file contained a `# fmt: off`.""" if isinstance(node, Node): for child in node.children: yield from self.visit(child) @@ -1211,7 +1317,7 @@ def whitespace(leaf: Leaf) -> str: # noqa C901 def preceding_leaf(node: Optional[LN]) -> Optional[Leaf]: - """Returns the first leaf that precedes `node`, if any.""" + """Return the first leaf that precedes `node`, if any.""" while node: res = node.prev_sibling if res: @@ -1229,7 +1335,7 @@ def preceding_leaf(node: Optional[LN]) -> Optional[Leaf]: def is_delimiter(leaf: Leaf) -> int: - """Returns the priority of the `leaf` delimiter. Returns 0 if not delimiter. + """Return the priority of the `leaf` delimiter. Return 0 if not delimiter. Higher numbers are higher priority. """ @@ -1250,7 +1356,7 @@ def is_delimiter(leaf: Leaf) -> int: def generate_comments(leaf: Leaf) -> Iterator[Leaf]: - """Cleans the prefix of the `leaf` and generates comments from it, if any. + """Clean the prefix of the `leaf` and generate comments from it, if any. Comments in lib2to3 are shoved into the whitespace prefix. This happens in `pgen2/driver.py:Driver.parse_tokens()`. This was a brilliant implementation @@ -1302,6 +1408,13 @@ def generate_comments(leaf: Leaf) -> Iterator[Leaf]: def make_comment(content: str) -> str: + """Return a consistently formatted comment from the given `content` string. + + All comments (except for "##", "#!", "#:") should have a single space between + the hash sign and the content. + + If `content` didn't start with a hash sign, one is provided. + """ content = content.rstrip() if not content: return '#' @@ -1316,7 +1429,7 @@ def make_comment(content: str) -> str: def split_line( line: Line, line_length: int, inner: bool = False, py36: bool = False ) -> Iterator[Line]: - """Splits a `line` into potentially many lines. + """Split a `line` into potentially many lines. They should fit in the allotted `line_length` but might not be able to. `inner` signifies that there were a pair of brackets somewhere around the @@ -1407,7 +1520,7 @@ def left_hand_split(line: Line, py36: bool = False) -> Iterator[Line]: comment_after = line.comments.get(id(leaf)) if comment_after: result.append(comment_after, preformatted=True) - split_succeeded_or_raise(head, body, tail) + bracket_split_succeeded_or_raise(head, body, tail) for result in (head, body, tail): if result: yield result @@ -1447,13 +1560,26 @@ def right_hand_split(line: Line, py36: bool = False) -> Iterator[Line]: comment_after = line.comments.get(id(leaf)) if comment_after: result.append(comment_after, preformatted=True) - split_succeeded_or_raise(head, body, tail) + bracket_split_succeeded_or_raise(head, body, tail) for result in (head, body, tail): if result: yield result -def split_succeeded_or_raise(head: Line, body: Line, tail: Line) -> None: +def bracket_split_succeeded_or_raise(head: Line, body: Line, tail: Line) -> None: + """Raise :exc:`CannotSplit` if the last left- or right-hand split failed. + + Do nothing otherwise. + + A left- or right-hand split is based on a pair of brackets. Content before + (and including) the opening bracket is left on one line, content inside the + brackets is put on a separate line, and finally content starting with and + following the closing bracket is put on a separate line. + + Those are called `head`, `body`, and `tail`, respectively. If the split + produced the same line (all content in `head`) or ended up with an empty `body` + and the `tail` is just the closing bracket, then it's considered failed. + """ tail_len = len(str(tail).strip()) if not body: if tail_len == 0: @@ -1471,7 +1597,7 @@ def delimiter_split(line: Line, py36: bool = False) -> Iterator[Line]: This kind of split doesn't increase indentation. If `py36` is True, the split will add trailing commas also in function - signatures that contain * and **. + signatures that contain `*` and `**`. """ try: last_leaf = line.leaves[-1] @@ -1480,7 +1606,9 @@ def delimiter_split(line: Line, py36: bool = False) -> Iterator[Line]: delimiters = line.bracket_tracker.delimiters try: - delimiter_priority = line.bracket_tracker.max_priority(exclude={id(last_leaf)}) + delimiter_priority = line.bracket_tracker.max_delimiter_priority( + exclude={id(last_leaf)} + ) except ValueError: raise CannotSplit("No delimiters found") @@ -1517,7 +1645,7 @@ def delimiter_split(line: Line, py36: bool = False) -> Iterator[Line]: def is_import(leaf: Leaf) -> bool: - """Returns True if the given leaf starts an import statement.""" + """Return True if the given leaf starts an import statement.""" p = leaf.parent t = leaf.type v = leaf.value @@ -1531,10 +1659,10 @@ def is_import(leaf: Leaf) -> bool: def normalize_prefix(leaf: Leaf, *, inside_brackets: bool) -> None: - """Leave existing extra newlines if not `inside_brackets`. + """Leave existing extra newlines if not `inside_brackets`. Remove everything + else. - Remove everything else. Note: don't use backslashes for formatting or - you'll lose your voting rights. + Note: don't use backslashes for formatting or you'll lose your voting rights. """ if not inside_brackets: spl = leaf.prefix.split('#') @@ -1549,7 +1677,7 @@ def normalize_prefix(leaf: Leaf, *, inside_brackets: bool) -> None: def is_python36(node: Node) -> bool: - """Returns True if the current file is using Python 3.6+ features. + """Return True if the current file is using Python 3.6+ features. Currently looking for: - f-strings; and @@ -1580,6 +1708,9 @@ BLACKLISTED_DIRECTORIES = { def gen_python_files_in_dir(path: Path) -> Iterator[Path]: + """Generate all files under `path` which aren't under BLACKLISTED_DIRECTORIES + and have one of the PYTHON_EXTENSIONS. + """ for child in path.iterdir(): if child.is_dir(): if child.name in BLACKLISTED_DIRECTORIES: @@ -1593,7 +1724,7 @@ def gen_python_files_in_dir(path: Path) -> Iterator[Path]: @dataclass class Report: - """Provides a reformatting counter.""" + """Provides a reformatting counter. Can be rendered with `str(report)`.""" check: bool = False change_count: int = 0 same_count: int = 0 @@ -1616,7 +1747,13 @@ class Report: @property def return_code(self) -> int: - """Which return code should the app use considering the current state.""" + """Return the exit code that the app should use. + + This considers the current state of changed files and failures: + - if there were any failures, return 123; + - if any files were changed and --check is being used, return 1; + - otherwise return 0. + """ # According to http://tldp.org/LDP/abs/html/exitcodes.html starting with # 126 we have special returncodes reserved by the shell. if self.failure_count: @@ -1628,7 +1765,7 @@ class Report: return 0 def __str__(self) -> str: - """A color report of the current state. + """Render a color report of the current state. Use `click.unstyle` to remove colors. """ @@ -1658,10 +1795,7 @@ class Report: def assert_equivalent(src: str, dst: str) -> None: - """Raises AssertionError if `src` and `dst` aren't equivalent. - - This is a temporary sanity check until Black becomes stable. - """ + """Raise AssertionError if `src` and `dst` aren't equivalent.""" import ast import traceback @@ -1724,10 +1858,7 @@ def assert_equivalent(src: str, dst: str) -> None: def assert_stable(src: str, dst: str, line_length: int) -> None: - """Raises AssertionError if `dst` reformats differently the second time. - - This is a temporary sanity check until Black becomes stable. - """ + """Raise AssertionError if `dst` reformats differently the second time.""" newdst = format_str(dst, line_length=line_length) if dst != newdst: log = dump_to_file( @@ -1743,7 +1874,7 @@ def assert_stable(src: str, dst: str, line_length: int) -> None: def dump_to_file(*output: str) -> str: - """Dumps `output` to a temporary file. Returns path to the file.""" + """Dump `output` to a temporary file. Return path to the file.""" import tempfile with tempfile.NamedTemporaryFile( @@ -1756,7 +1887,7 @@ def dump_to_file(*output: str) -> str: def diff(a: str, b: str, a_name: str, b_name: str) -> str: - """Returns a udiff string between strings `a` and `b`.""" + """Return a unified diff string between strings `a` and `b`.""" import difflib a_lines = [line + '\n' for line in a.split('\n')]