X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/7bd6f3cb2ff11d385dbe433e2b03e9f7c94be33e..d01460d9393d611c0673723320f7a1e50c424e21:/black.py diff --git a/black.py b/black.py index e39cf7d..a61a40f 100644 --- a/black.py +++ b/black.py @@ -10,7 +10,7 @@ from pathlib import Path import tokenize import sys from typing import ( - Dict, Generic, Iterable, Iterator, List, Optional, Set, Tuple, TypeVar, Union + Dict, Generic, Iterable, Iterator, List, Optional, Set, Tuple, Type, TypeVar, Union ) from attr import dataclass, Factory @@ -22,7 +22,7 @@ from blib2to3 import pygram, pytree from blib2to3.pgen2 import driver, token from blib2to3.pgen2.parse import ParseError -__version__ = "18.3a3" +__version__ = "18.3a4" DEFAULT_LINE_LENGTH = 88 # types syms = pygram.python_symbols @@ -48,6 +48,34 @@ class CannotSplit(Exception): """ +class FormatError(Exception): + """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. + """ + + def __init__(self, consumed: int) -> None: + super().__init__(consumed) + self.consumed = consumed + + def trim_prefix(self, leaf: Leaf) -> None: + leaf.prefix = leaf.prefix[self.consumed:] + + def leaf_from_consumed(self, leaf: Leaf) -> Leaf: + """Returns a new Leaf from the consumed part of the prefix.""" + unformatted_prefix = leaf.prefix[:self.consumed] + return Leaf(token.NEWLINE, unformatted_prefix) + + +class FormatOn(FormatError): + """Found a comment like `# fmt: on` in the file.""" + + +class FormatOff(FormatError): + """Found a comment like `# fmt: off` in the file.""" + + @click.command() @click.option( '-l', @@ -281,9 +309,18 @@ 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 start the visit process. Yields objects of type `T`. + + 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: @@ -291,6 +328,7 @@ 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) @@ -320,6 +358,15 @@ class DebugVisitor(Visitor[T]): out(f' {node.prefix!r}', fg='green', bold=False, nl=False) out(f' {node.value!r}', fg='blue', bold=False) + @classmethod + def show(cls, code: str) -> None: + """Pretty-prints a given string of `code`. + + Convenience method for debugging. + """ + v: DebugVisitor[None] = DebugVisitor() + list(v.visit(lib2to3_parse(code))) + KEYWORDS = set(keyword.kwlist) WHITESPACE = {token.DEDENT, token.INDENT, token.NEWLINE} @@ -369,12 +416,32 @@ MATH_PRIORITY = 1 @dataclass class BracketTracker: + """Keeps track of brackets on a line.""" + + #: Current bracket depth. depth: int = 0 + #: All currently unclosed brackets. bracket_match: Dict[Tuple[Depth, NodeType], Leaf] = Factory(dict) + #: All current delimiters with their assigned priority. delimiters: Dict[LeafID, Priority] = Factory(dict) + #: Last processed leaf, if any. previous: Optional[Leaf] = None def mark(self, leaf: Leaf) -> None: + """Marks `leaf` with bracket-related metadata. Keeps 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 @@ -419,7 +486,7 @@ class BracketTracker: """Returns 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: + def max_delimiter_priority(self, exclude: Iterable[LeafID] = ()) -> int: """Returns the highest priority of a delimiter found on the line. Values are consistent with what `is_delimiter()` returns. @@ -429,8 +496,13 @@ class BracketTracker: @dataclass class Line: + """Holds leaves and comments. Can be printed with `str(line)`.""" + + #: indentation level depth: int = 0 + #: list of leaves leaves: List[Leaf] = Factory(list) + #: inline comments that belong on this line comments: Dict[LeafID, Leaf] = Factory(dict) bracket_tracker: BracketTracker = Factory(BracketTracker) inside_brackets: bool = False @@ -438,6 +510,15 @@ 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 @@ -459,18 +540,22 @@ 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 a class definition?""" return ( bool(self) and self.leaves[0].type == token.NAME @@ -479,7 +564,7 @@ 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: @@ -501,6 +586,10 @@ class Line: @property def is_flow_control(self) -> bool: + """Is this a flow control statement? + + Those are `return`, `raise`, `break`, and `continue`. + """ return ( bool(self) and self.leaves[0].type == token.NAME @@ -509,6 +598,7 @@ class Line: @property def is_yield(self) -> bool: + """Is this a yield statement?""" return ( bool(self) and self.leaves[0].type == token.NAME @@ -516,6 +606,7 @@ 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 @@ -578,7 +669,7 @@ 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 @@ -606,6 +697,7 @@ 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 @@ -624,6 +716,7 @@ class Line: return True def last_non_delimiter(self) -> Leaf: + """Returns the last non-delimiter on the line. Raises LookupError otherwise.""" for i in range(len(self.leaves)): last = self.leaves[-i - 1] if not is_delimiter(last): @@ -632,6 +725,7 @@ class Line: raise LookupError("No non-delimiters found") def __str__(self) -> str: + """Render the line.""" if not self: return '\n' @@ -646,9 +740,63 @@ class Line: return res + '\n' def __bool__(self) -> bool: + """Returns 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 = 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: + self.leaves.append(f_on.leaf_from_consumed(leaf)) + raise + + self.leaves.append(leaf) + if leaf.type == token.INDENT: + self.depth += 1 + elif leaf.type == token.DEDENT: + self.depth -= 1 + + def append_comment(self, comment: Leaf) -> bool: + """Not implemented in this class.""" + 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: + """Renders 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 + + @dataclass class EmptyLineTracker: """Provides a stateful method that returns the number of potential extra @@ -669,6 +817,9 @@ class EmptyLineTracker: (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 + before, after = self._maybe_empty_lines(current_line) before -= self.previous_after self.previous_after = after @@ -677,13 +828,13 @@ 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 @@ -738,7 +889,7 @@ class LineGenerator(Visitor[Line]): """ current_line: Line = Factory(Line) - def line(self, indent: int = 0) -> Iterator[Line]: + def line(self, indent: int = 0, type: Type[Line] = Line) -> Iterator[Line]: """Generate a line. If the line is empty, only emit if it makes sense. @@ -747,49 +898,82 @@ class LineGenerator(Visitor[Line]): If any lines were generated, set up a new current_line. """ if not self.current_line: - self.current_line.depth += indent + if self.current_line.__class__ == type: + self.current_line.depth += indent + else: + self.current_line = type(depth=self.current_line.depth + indent) return # Line is empty, don't emit. Creating a new one unnecessary. complete_line = self.current_line - self.current_line = Line(depth=complete_line.depth + indent) + self.current_line = type(depth=complete_line.depth + indent) yield complete_line + def visit(self, node: LN) -> Iterator[Line]: + """Main method to start the visit process. Yields :class:`Line` objects.""" + if isinstance(self.current_line, UnformattedLines): + # File contained `# fmt: off` + yield from self.visit_unformatted(node) + + else: + 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() - for comment in generate_comments(node): - if any_open_brackets: - # any comment within brackets is subject to splitting - self.current_line.append(comment) - elif comment.type == token.COMMENT: - # regular trailing comment - self.current_line.append(comment) - yield from self.line() - - else: - # regular standalone comment - yield from self.line() - - self.current_line.append(comment) - yield from self.line() - - normalize_prefix(node, inside_brackets=any_open_brackets) - if node.type not in WHITESPACE: - self.current_line.append(node) + try: + for comment in generate_comments(node): + if any_open_brackets: + # any comment within brackets is subject to splitting + self.current_line.append(comment) + elif comment.type == token.COMMENT: + # regular trailing comment + self.current_line.append(comment) + yield from self.line() + + else: + # regular standalone comment + yield from self.line() + + self.current_line.append(comment) + yield from self.line() + + except FormatOff as f_off: + f_off.trim_prefix(node) + yield from self.line(type=UnformattedLines) + yield from self.visit(node) + + except FormatOn as f_on: + # This only happens here if somebody says "fmt: on" multiple + # times in a row. + f_on.trim_prefix(node) + yield from self.visit_default(node) + + else: + normalize_prefix(node, inside_brackets=any_open_brackets) + if node.type not in WHITESPACE: + self.current_line.append(node) yield from super().visit_default(node) def visit_INDENT(self, node: Node) -> Iterator[Line]: + """Increases indentation level, maybe yields 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]: + """Decreases indentation level, maybe yields 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. + """Visits a statement. + + This implementation is shared for `if`, `while`, `for`, `try`, `except`, + `def`, `with`, and `class`. - The relevant Python language keywords for this statement are NAME leaves - within it. + 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 @@ -798,7 +982,7 @@ class LineGenerator(Visitor[Line]): yield from self.visit(child) def visit_simple_stmt(self, node: Node) -> Iterator[Line]: - """A statement without nested statements.""" + """Visits 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) @@ -810,6 +994,7 @@ class LineGenerator(Visitor[Line]): yield from self.visit_default(node) def visit_async_stmt(self, node: Node) -> Iterator[Line]: + """Visits `async def`, `async for`, `async with`.""" yield from self.line() children = iter(node.children) @@ -824,17 +1009,40 @@ class LineGenerator(Visitor[Line]): yield from self.visit(child) def visit_decorators(self, node: Node) -> Iterator[Line]: + """Visits decorators.""" for child in node.children: yield from self.line() yield from self.visit(child) def visit_SEMI(self, leaf: Leaf) -> Iterator[Line]: + """Semicolons are always removed. + + Statements between them are put on separate lines. + """ 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) + + else: + try: + self.current_line.append(node) + except FormatOn as f_on: + f_on.trim_prefix(node) + yield from self.line() + yield from self.visit(node) + def __attrs_post_init__(self) -> None: """You are in a twisty little maze of passages.""" v = self.visit_stmt @@ -885,14 +1093,17 @@ def whitespace(leaf: Leaf) -> str: # noqa C901 return SPACE if prevp.type == token.COMMA else NO if prevp.type == token.EQUAL: - if prevp.parent and prevp.parent.type in { - syms.arglist, - syms.argument, - syms.parameters, - syms.typedargslist, - syms.varargslist, - }: - return NO + if prevp.parent: + if prevp.parent.type in { + syms.arglist, syms.argument, syms.parameters, syms.varargslist + }: + return NO + + elif prevp.parent.type == syms.typedargslist: + # A bit hacky: if the equal sign has whitespace, it means we + # previously found it's a typed argument. So, we're using + # that, too. + return prevp.prefix elif prevp.type == token.DOUBLESTAR: if prevp.parent and prevp.parent.type in { @@ -938,7 +1149,7 @@ def whitespace(leaf: Leaf) -> str: # noqa C901 if not prev or prev.type != token.COMMA: return NO - if p.type == syms.varargslist: + elif p.type == syms.varargslist: # lambdas if t == token.RPAR: return NO @@ -1156,8 +1367,10 @@ def generate_comments(leaf: Leaf) -> Iterator[Leaf]: if '#' not in p: return + consumed = 0 nlines = 0 for index, line in enumerate(p.split('\n')): + consumed += len(line) + 1 # adding the length of the split '\n' line = line.lstrip() if not line: nlines += 1 @@ -1168,19 +1381,33 @@ def generate_comments(leaf: Leaf) -> Iterator[Leaf]: comment_type = token.COMMENT # simple trailing comment else: comment_type = STANDALONE_COMMENT - yield Leaf(comment_type, make_comment(line), prefix='\n' * nlines) + comment = make_comment(line) + yield Leaf(comment_type, comment, prefix='\n' * nlines) + + if comment in {'# fmt: on', '# yapf: enable'}: + raise FormatOn(consumed) + + if comment in {'# fmt: off', '# yapf: disable'}: + raise FormatOff(consumed) nlines = 0 def make_comment(content: str) -> str: + """Returns 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 '#' if content[0] == '#': content = content[1:] - if content and content[0] not in {' ', '!', '#'}: + if content and content[0] not in ' !:#': content = ' ' + content return '#' + content @@ -1198,6 +1425,10 @@ def split_line( If `py36` is True, splitting may generate syntax that is only compatible with Python 3.6 and later. """ + if isinstance(line, UnformattedLines): + yield line + return + line_str = str(line).strip('\n') if len(line_str) <= line_length and '\n' not in line_str: yield line @@ -1238,7 +1469,7 @@ def split_line( def left_hand_split(line: Line, py36: bool = False) -> Iterator[Line]: - """Split line into many lines, starting with the first matching bracket pair. + """Splits line into many lines, starting with the first matching bracket pair. Note: this usually looks weird, only use this for function definitions. Prefer RHS otherwise. @@ -1275,14 +1506,14 @@ 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 def right_hand_split(line: Line, py36: bool = False) -> Iterator[Line]: - """Split line into many lines, starting with the last matching bracket pair.""" + """Splits line into many lines, starting with the last matching bracket pair.""" head = Line(depth=line.depth) body = Line(depth=line.depth + 1, inside_brackets=True) tail = Line(depth=line.depth) @@ -1315,13 +1546,26 @@ 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: @@ -1335,11 +1579,11 @@ def split_succeeded_or_raise(head: Line, body: Line, tail: Line) -> None: def delimiter_split(line: Line, py36: bool = False) -> Iterator[Line]: - """Split according to delimiters of the highest priority. + """Splits according to delimiters of the highest priority. 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] @@ -1348,7 +1592,9 @@ 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") @@ -1399,9 +1645,9 @@ def is_import(leaf: Leaf) -> bool: def normalize_prefix(leaf: Leaf, *, inside_brackets: bool) -> None: - """Leave existing extra newlines if not `inside_brackets`. + """Leaves existing extra newlines if not `inside_brackets`. - Remove everything else. Note: don't use backslashes for formatting or + Removes everything else. Note: don't use backslashes for formatting or you'll lose your voting rights. """ if not inside_brackets: @@ -1448,6 +1694,9 @@ BLACKLISTED_DIRECTORIES = { def gen_python_files_in_dir(path: Path) -> Iterator[Path]: + """Generates 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: @@ -1461,7 +1710,7 @@ 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