X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/3eea3aad864b83af3b6c477c32f15eb821fe9341..7395f55564a689a28db5ab3f82c079f7fc40eadf:/black.py diff --git a/black.py b/black.py index 7823ae0..57cd9a6 100644 --- a/black.py +++ b/black.py @@ -30,6 +30,7 @@ from typing import ( Type, TypeVar, Union, + cast, ) from appdirs import user_cache_dir @@ -43,7 +44,7 @@ from blib2to3.pgen2 import driver, token from blib2to3.pgen2.parse import ParseError -__version__ = "18.4a6" +__version__ = "18.5b0" DEFAULT_LINE_LENGTH = 88 # types @@ -239,11 +240,8 @@ def reformat_one( src = src.resolve() if src in cache and cache[src] == get_cache_info(src): changed = Changed.CACHED - if ( - changed is not Changed.CACHED - and format_file_in_place( - src, line_length=line_length, fast=fast, write_back=write_back - ) + if changed is not Changed.CACHED and format_file_in_place( + src, line_length=line_length, fast=fast, write_back=write_back ): changed = Changed.YES if write_back == WriteBack.YES and changed is not Changed.NO: @@ -285,32 +283,29 @@ async def schedule_formatting( manager = Manager() lock = manager.Lock() tasks = { - src: loop.run_in_executor( + loop.run_in_executor( executor, format_file_in_place, src, line_length, fast, write_back, lock - ) - for src in sources + ): src + for src in sorted(sources) } - _task_values = list(tasks.values()) + pending: Iterable[asyncio.Task] = tasks.keys() try: - loop.add_signal_handler(signal.SIGINT, cancel, _task_values) - loop.add_signal_handler(signal.SIGTERM, cancel, _task_values) + loop.add_signal_handler(signal.SIGINT, cancel, pending) + loop.add_signal_handler(signal.SIGTERM, cancel, pending) except NotImplementedError: # There are no good alternatives for these on Windows pass - await asyncio.wait(_task_values) - for src, task in tasks.items(): - if not task.done(): - report.failed(src, "timed out, cancelling") - task.cancel() - cancelled.append(task) - elif task.cancelled(): - cancelled.append(task) - elif task.exception(): - report.failed(src, str(task.exception())) - else: - formatted.append(src) - report.done(src, Changed.YES if task.result() else Changed.NO) - + while pending: + done, _ = await asyncio.wait(pending, return_when=asyncio.FIRST_COMPLETED) + for task in done: + src = tasks.pop(task) + if task.cancelled(): + cancelled.append(task) + elif task.exception(): + report.failed(src, str(task.exception())) + else: + formatted.append(src) + report.done(src, Changed.YES if task.result() else Changed.NO) if cancelled: await asyncio.gather(*cancelled, loop=loop, return_exceptions=True) if write_back == WriteBack.YES and formatted: @@ -329,12 +324,13 @@ def format_file_in_place( If `write_back` is True, write reformatted code back to stdout. `line_length` and `fast` options are passed to :func:`format_file_contents`. """ + is_pyi = src.suffix == ".pyi" with tokenize.open(src) as src_buffer: src_contents = src_buffer.read() try: dst_contents = format_file_contents( - src_contents, line_length=line_length, fast=fast + src_contents, line_length=line_length, fast=fast, is_pyi=is_pyi ) except NothingChanged: return False @@ -383,7 +379,7 @@ def format_stdin_to_stdout( def format_file_contents( - src_contents: str, line_length: int, fast: bool + src_contents: str, *, line_length: int, fast: bool, is_pyi: bool = False ) -> FileContent: """Reformat contents a file and return new contents. @@ -394,17 +390,21 @@ def format_file_contents( if src_contents.strip() == "": raise NothingChanged - dst_contents = format_str(src_contents, line_length=line_length) + dst_contents = format_str(src_contents, line_length=line_length, is_pyi=is_pyi) if src_contents == dst_contents: raise NothingChanged if not fast: assert_equivalent(src_contents, dst_contents) - assert_stable(src_contents, dst_contents, line_length=line_length) + assert_stable( + src_contents, dst_contents, line_length=line_length, is_pyi=is_pyi + ) return dst_contents -def format_str(src_contents: str, line_length: int) -> FileContent: +def format_str( + src_contents: str, line_length: int, *, is_pyi: bool = False +) -> FileContent: """Reformat a string and return new contents. `line_length` determines how many characters per line are allowed. @@ -412,9 +412,11 @@ def format_str(src_contents: str, line_length: int) -> FileContent: src_node = lib2to3_parse(src_contents) dst_contents = "" future_imports = get_future_imports(src_node) + elt = EmptyLineTracker(is_pyi=is_pyi) py36 = is_python36(src_node) - lines = LineGenerator(remove_u_prefix=py36 or "unicode_literals" in future_imports) - elt = EmptyLineTracker() + lines = LineGenerator( + remove_u_prefix=py36 or "unicode_literals" in future_imports, is_pyi=is_pyi + ) empty_line = Line() after = 0 for current_line in lines.visit(src_node): @@ -625,21 +627,22 @@ LOGIC_PRIORITY = 14 STRING_PRIORITY = 12 COMPARATOR_PRIORITY = 10 MATH_PRIORITIES = { - token.VBAR: 8, - token.CIRCUMFLEX: 7, - token.AMPER: 6, - token.LEFTSHIFT: 5, - token.RIGHTSHIFT: 5, - token.PLUS: 4, - token.MINUS: 4, - token.STAR: 3, - token.SLASH: 3, - token.DOUBLESLASH: 3, - token.PERCENT: 3, - token.AT: 3, - token.TILDE: 2, - token.DOUBLESTAR: 1, + token.VBAR: 9, + token.CIRCUMFLEX: 8, + token.AMPER: 7, + token.LEFTSHIFT: 6, + token.RIGHTSHIFT: 6, + token.PLUS: 5, + token.MINUS: 5, + token.STAR: 4, + token.SLASH: 4, + token.DOUBLESLASH: 4, + token.PERCENT: 4, + token.AT: 4, + token.TILDE: 3, + token.DOUBLESTAR: 2, } +DOT_PRIORITY = 1 @dataclass @@ -705,6 +708,17 @@ class BracketTracker: """ return max(v for k, v in self.delimiters.items() if k not in exclude) + def delimiter_count_with_priority(self, priority: int = 0) -> int: + """Return the number of delimiters with the given `priority`. + + If no `priority` is passed, defaults to max priority on the line. + """ + if not self.delimiters: + return 0 + + priority = priority or self.max_delimiter_priority() + return sum(1 for p in self.delimiters.values() if p == priority) + def maybe_increment_for_loop_variable(self, leaf: Leaf) -> bool: """In a for loop, or comprehension, the variables are often unpacks. @@ -763,6 +777,7 @@ class Line: comments: List[Tuple[Index, Leaf]] = Factory(list) bracket_tracker: BracketTracker = Factory(BracketTracker) inside_brackets: bool = False + should_explode: bool = False def append(self, leaf: Leaf, preformatted: bool = False) -> None: """Add a new `leaf` to the end of the line. @@ -833,6 +848,13 @@ class Line: and self.leaves[0].value == "class" ) + @property + def is_stub_class(self) -> bool: + """Is this line a class definition with a body consisting only of "..."?""" + return self.is_class and self.leaves[-3:] == [ + Leaf(token.DOT, ".") for _ in range(3) + ] + @property def is_def(self) -> bool: """Is this a function definition? (Also returns True for async defs.)""" @@ -845,14 +867,11 @@ class Line: second_leaf: Optional[Leaf] = self.leaves[1] except IndexError: second_leaf = None - return ( - (first_leaf.type == token.NAME and first_leaf.value == "def") - or ( - first_leaf.type == token.ASYNC - and second_leaf is not None - and second_leaf.type == token.NAME - and second_leaf.value == "def" - ) + return (first_leaf.type == token.NAME and first_leaf.value == "def") or ( + first_leaf.type == token.ASYNC + and second_leaf is not None + and second_leaf.type == token.NAME + and second_leaf.value == "def" ) @property @@ -1017,9 +1036,8 @@ class Line: and subscript_start.type == syms.subscriptlist ): subscript_start = child_towards(subscript_start, leaf) - return ( - subscript_start is not None - and any(n.type in TEST_DESCENDANTS for n in subscript_start.pre_order()) + return subscript_start is not None and any( + n.type in TEST_DESCENDANTS for n in subscript_start.pre_order() ) def __str__(self) -> str: @@ -1100,6 +1118,7 @@ class EmptyLineTracker: the prefix of the first leaf consists of optional newlines. Those newlines are consumed by `maybe_empty_lines()` and included in the computation. """ + is_pyi: bool = False previous_line: Optional[Line] = None previous_after: int = 0 previous_defs: List[int] = Factory(list) @@ -1123,7 +1142,7 @@ class EmptyLineTracker: def _maybe_empty_lines(self, current_line: Line) -> Tuple[int, int]: max_allowed = 1 if current_line.depth == 0: - max_allowed = 2 + max_allowed = 1 if self.is_pyi else 2 if current_line.leaves: # Consume the first leaf's extra newlines. first_leaf = current_line.leaves[0] @@ -1135,7 +1154,10 @@ class EmptyLineTracker: depth = current_line.depth while self.previous_defs and self.previous_defs[-1] >= depth: self.previous_defs.pop() - before = 1 if depth else 2 + if self.is_pyi: + before = 0 if depth else 1 + else: + before = 1 if depth else 2 is_decorator = current_line.is_decorator if is_decorator or current_line.is_def or current_line.is_class: if not is_decorator: @@ -1154,8 +1176,19 @@ class EmptyLineTracker: ): return 0, 0 - newlines = 2 - if current_line.depth: + if self.is_pyi: + if self.previous_line.depth > current_line.depth: + newlines = 1 + elif current_line.is_class or self.previous_line.is_class: + if current_line.is_stub_class and self.previous_line.is_stub_class: + newlines = 0 + else: + newlines = 1 + else: + newlines = 0 + else: + newlines = 2 + if current_line.depth and newlines: newlines -= 1 return newlines, 0 @@ -1177,6 +1210,7 @@ class LineGenerator(Visitor[Line]): Note: destroys the tree it's visiting by mutating prefixes of its leaves in ways that will no longer stringify to valid Python code on the tree. """ + is_pyi: bool = False current_line: Line = Factory(Line) remove_u_prefix: bool = False @@ -1283,7 +1317,7 @@ class LineGenerator(Visitor[Line]): The relevant Python language `keywords` for a given statement will be NAME leaves within it. This methods puts those on a separate line. - `parens` holds a set of string leaf values immeditely after which + `parens` holds a set of string leaf values immediately after which invisible parens should be put. """ normalize_invisible_parens(node, parens_after=parens) @@ -1293,16 +1327,27 @@ class LineGenerator(Visitor[Line]): yield from self.visit(child) + def visit_suite(self, node: Node) -> Iterator[Line]: + """Visit a suite.""" + if self.is_pyi and is_stub_suite(node): + yield from self.visit(node.children[2]) + else: + yield from self.visit_default(node) + def visit_simple_stmt(self, node: Node) -> Iterator[Line]: """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) - yield from self.visit_default(node) - yield from self.line(-1) + if self.is_pyi and is_stub_body(node): + yield from self.visit_default(node) + else: + yield from self.line(+1) + yield from self.visit_default(node) + yield from self.line(-1) else: - yield from self.line() + if not self.is_pyi or not node.parent or not is_stub_suite(node.parent): + yield from self.line() yield from self.visit_default(node) def visit_async_stmt(self, node: Node) -> Iterator[Line]: @@ -1429,10 +1474,11 @@ def whitespace(leaf: Leaf, *, complex_subscript: bool) -> str: # noqa C901 return DOUBLESPACE assert p is not None, f"INTERNAL ERROR: hand-made leaf without parent: {leaf!r}" - if ( - t == token.COLON - and p.type not in {syms.subscript, syms.subscriptlist, syms.sliceop} - ): + if t == token.COLON and p.type not in { + syms.subscript, + syms.subscriptlist, + syms.sliceop, + }: return NO prev = leaf.prev_sibling @@ -1453,7 +1499,10 @@ def whitespace(leaf: Leaf, *, complex_subscript: bool) -> str: # noqa C901 if prevp.type == token.EQUAL: if prevp.parent: if prevp.parent.type in { - syms.arglist, syms.argument, syms.parameters, syms.varargslist + syms.arglist, + syms.argument, + syms.parameters, + syms.varargslist, }: return NO @@ -1606,10 +1655,10 @@ def whitespace(leaf: Leaf, *, complex_subscript: bool) -> str: # noqa C901 prevp_parent = prevp.parent assert prevp_parent is not None - if ( - prevp.type == token.COLON - and prevp_parent.type in {syms.subscript, syms.sliceop} - ): + if prevp.type == token.COLON and prevp_parent.type in { + syms.subscript, + syms.sliceop, + }: return NO elif prevp.type == token.EQUAL and prevp_parent.type == syms.argument: @@ -1689,6 +1738,14 @@ def is_split_before_delimiter(leaf: Leaf, previous: Leaf = None) -> int: # Don't treat them as a delimiter. return 0 + if ( + leaf.type == token.DOT + and leaf.parent + and leaf.parent.type not in {syms.import_from, syms.dotted_name} + and (previous is None or previous.type in CLOSING_BRACKETS) + ): + return DOT_PRIORITY + if ( leaf.type in MATH_OPERATORS and leaf.parent @@ -1706,31 +1763,54 @@ def is_split_before_delimiter(leaf: Leaf, previous: Leaf = None) -> int: ): return STRING_PRIORITY + if leaf.type != token.NAME: + return 0 + if ( - leaf.type == token.NAME - and leaf.value == "for" + leaf.value == "for" and leaf.parent and leaf.parent.type in {syms.comp_for, syms.old_comp_for} ): return COMPREHENSION_PRIORITY if ( - leaf.type == token.NAME - and leaf.value == "if" + leaf.value == "if" and leaf.parent and leaf.parent.type in {syms.comp_if, syms.old_comp_if} ): return COMPREHENSION_PRIORITY + if leaf.value in {"if", "else"} and leaf.parent and leaf.parent.type == syms.test: + return TERNARY_PRIORITY + + if leaf.value == "is": + return COMPARATOR_PRIORITY + if ( - leaf.type == token.NAME - and leaf.value in {"if", "else"} + leaf.value == "in" and leaf.parent - and leaf.parent.type == syms.test + and leaf.parent.type in {syms.comp_op, syms.comparison} + and not ( + previous is not None + and previous.type == token.NAME + and previous.value == "not" + ) ): - return TERNARY_PRIORITY + return COMPARATOR_PRIORITY - if leaf.type == token.NAME and leaf.value in LOGIC_OPERATORS and leaf.parent: + if ( + leaf.value == "not" + and leaf.parent + and leaf.parent.type == syms.comp_op + and not ( + previous is not None + and previous.type == token.NAME + and previous.value == "is" + ) + ): + return COMPARATOR_PRIORITY + + if leaf.value in LOGIC_OPERATORS and leaf.parent: return LOGIC_PRIORITY return 0 @@ -1830,25 +1910,27 @@ def split_line( return line_str = str(line).strip("\n") - if is_line_short_enough(line, line_length=line_length, line_str=line_str): + if not line.should_explode and is_line_short_enough( + line, line_length=line_length, line_str=line_str + ): yield line return split_funcs: List[SplitFunc] if line.is_def: split_funcs = [left_hand_split] - elif line.is_import: - split_funcs = [explode_split] else: def rhs(line: Line, py36: bool = False) -> Iterator[Line]: for omit in generate_trailers_to_omit(line, line_length): - lines = list(right_hand_split(line, py36, omit=omit)) + lines = list(right_hand_split(line, line_length, py36, omit=omit)) if is_line_short_enough(lines[0], line_length=line_length): yield from lines return # All splits failed, best effort split with no omits. + # This mostly happens to multiline strings that are by definition + # reported as not fitting a single line. yield from right_hand_split(line, py36) if line.inside_brackets: @@ -1922,13 +2004,15 @@ def left_hand_split(line: Line, py36: bool = False) -> Iterator[Line]: def right_hand_split( - line: Line, py36: bool = False, omit: Collection[LeafID] = () + line: Line, line_length: int, py36: bool = False, omit: Collection[LeafID] = () ) -> Iterator[Line]: """Split line into many lines, starting with the last matching bracket pair. If the split was by optional parentheses, attempt splitting without them, too. `omit` is a collection of closing bracket IDs that shouldn't be considered for this split. + + Note: running this function modifies `bracket_depth` on the leaves of `line`. """ head = Line(depth=line.depth) body = Line(depth=line.depth + 1, inside_brackets=True) @@ -1955,8 +2039,9 @@ def right_hand_split( # Since body is a new indent level, remove spurious leading whitespace. if body_leaves: normalize_prefix(body_leaves[0], inside_brackets=True) - elif not head_leaves: - # No `head` and no `body` means the split failed. `tail` has all content. + if not head_leaves: + # No `head` means the split failed. Either `tail` has all content or + # the matching `opening_bracket` wasn't available on `line` anymore. raise CannotSplit("No brackets found") # Build the new lines. @@ -1974,22 +2059,23 @@ def right_hand_split( # the closing bracket is an optional paren and closing_bracket.type == token.RPAR and not closing_bracket.value - # there are no delimiters or standalone comments in the body - and not body.bracket_tracker.delimiters + # there are no standalone comments in the body and not line.contains_standalone_comments(0) # and it's not an import (optional parens are the only thing we can split # on in this case; attempting a split without them is a waste of time) and not line.is_import ): omit = {id(closing_bracket), *omit} - try: - yield from right_hand_split(line, py36=py36, omit=omit) - return - except CannotSplit: - pass + if can_omit_invisible_parens(body, line_length): + try: + yield from right_hand_split(line, line_length, py36=py36, omit=omit) + return + except CannotSplit: + pass ensure_visible(opening_bracket) ensure_visible(closing_bracket) + body.should_explode = should_explode(body, opening_bracket) for result in (head, body, tail): if result: yield result @@ -2048,14 +2134,16 @@ def delimiter_split(line: Line, py36: bool = False) -> Iterator[Line]: except IndexError: raise CannotSplit("Line empty") - delimiters = line.bracket_tracker.delimiters + bt = line.bracket_tracker try: - delimiter_priority = line.bracket_tracker.max_delimiter_priority( - exclude={id(last_leaf)} - ) + delimiter_priority = bt.max_delimiter_priority(exclude={id(last_leaf)}) except ValueError: raise CannotSplit("No delimiters found") + if delimiter_priority == DOT_PRIORITY: + if bt.delimiter_count_with_priority(delimiter_priority) == 1: + raise CannotSplit("Splitting a single attribute from its owner looks wrong") + current_line = Line(depth=line.depth, inside_brackets=line.inside_brackets) lowest_depth = sys.maxsize trailing_comma_safe = True @@ -2078,12 +2166,11 @@ def delimiter_split(line: Line, py36: bool = False) -> Iterator[Line]: yield from append_to_line(comment_after) lowest_depth = min(lowest_depth, leaf.bracket_depth) - if ( - leaf.bracket_depth == lowest_depth - and is_vararg(leaf, within=VARARGS_PARENTS) + if leaf.bracket_depth == lowest_depth and is_vararg( + leaf, within=VARARGS_PARENTS ): trailing_comma_safe = trailing_comma_safe and py36 - leaf_priority = delimiters.get(id(leaf)) + leaf_priority = bt.delimiters.get(id(leaf)) if leaf_priority == delimiter_priority: yield current_line @@ -2128,26 +2215,6 @@ def standalone_comment_split(line: Line, py36: bool = False) -> Iterator[Line]: yield current_line -def explode_split( - line: Line, py36: bool = False, omit: Collection[LeafID] = () -) -> Iterator[Line]: - """Split by rightmost bracket and immediately split contents by a delimiter.""" - new_lines = list(right_hand_split(line, py36, omit)) - if len(new_lines) != 3: - yield from new_lines - return - - yield new_lines[0] - - try: - yield from delimiter_split(new_lines[1], py36) - - except CannotSplit: - yield new_lines[1] - - yield new_lines[2] - - def is_import(leaf: Leaf) -> bool: """Return True if the given leaf starts an import statement.""" p = leaf.parent @@ -2277,7 +2344,7 @@ def normalize_invisible_parens(node: Node, parens_after: Set[str]) -> None: rpar = Leaf(token.RPAR, ")") index = child.remove() or 0 node.insert_child(index, Node(syms.atom, [lpar, child, rpar])) - else: + elif not (isinstance(child, Leaf) and is_multiline_string(child)): # wrap child in invisible parentheses lpar = Leaf(token.LPAR, "") rpar = Leaf(token.RPAR, "") @@ -2388,6 +2455,41 @@ def is_vararg(leaf: Leaf, within: Set[NodeType]) -> bool: return p.type in within +def is_multiline_string(leaf: Leaf) -> bool: + """Return True if `leaf` is a multiline string that actually spans many lines.""" + value = leaf.value.lstrip("furbFURB") + return value[:3] in {'"""', "'''"} and "\n" in value + + +def is_stub_suite(node: Node) -> bool: + """Return True if `node` is a suite with a stub body.""" + if ( + len(node.children) != 4 + or node.children[0].type != token.NEWLINE + or node.children[1].type != token.INDENT + or node.children[3].type != token.DEDENT + ): + return False + + return is_stub_body(node.children[2]) + + +def is_stub_body(node: LN) -> bool: + """Return True if `node` is a simple statement containing an ellipsis.""" + if not isinstance(node, Node) or node.type != syms.simple_stmt: + return False + + if len(node.children) != 2: + return False + + child = node.children[0] + return ( + child.type == syms.atom + and len(child.children) == 3 + and all(leaf == Leaf(token.DOT, ".") for leaf in child.children) + ) + + def max_delimiter_priority_in_atom(node: LN) -> int: """Return maximum delimiter priority inside `node`. @@ -2428,6 +2530,25 @@ def ensure_visible(leaf: Leaf) -> None: leaf.value = ")" +def should_explode(line: Line, opening_bracket: Leaf) -> bool: + """Should `line` immediately be split with `delimiter_split()` after RHS?""" + if not ( + opening_bracket.parent + and opening_bracket.parent.type in {syms.atom, syms.import_from} + and opening_bracket.value in "[{(" + ): + return False + + try: + last_leaf = line.leaves[-1] + exclude = {id(last_leaf)} if last_leaf.type == token.COMMA else set() + max_priority = line.bracket_tracker.max_delimiter_priority(exclude=exclude) + except (IndexError, ValueError): + return False + + return max_priority == COMMA_PRIORITY + + def is_python36(node: Node) -> bool: """Return True if the current file is using Python 3.6+ features. @@ -2476,22 +2597,11 @@ def generate_trailers_to_omit(line: Line, line_length: int) -> Iterator[Set[Leaf closing_bracket = None optional_brackets: Set[LeafID] = set() inner_brackets: Set[LeafID] = set() - for index, leaf in enumerate_reversed(line.leaves): - length += len(leaf.prefix) + len(leaf.value) + for index, leaf, leaf_length in enumerate_with_length(line, reversed=True): + length += leaf_length if length > line_length: break - comment: Optional[Leaf] - for comment in line.comments_after(leaf, index): - if "\n" in comment.prefix: - break # Oops, standalone comment! - - length += len(comment.value) - else: - comment = None - if comment is not None: - break # There was a standalone comment, we can't continue. - optional_brackets.discard(id(leaf)) if opening_bracket: if leaf is opening_bracket: @@ -2554,9 +2664,17 @@ def get_future_imports(node: Node) -> Set[str]: return imports -PYTHON_EXTENSIONS = {".py"} +PYTHON_EXTENSIONS = {".py", ".pyi"} BLACKLISTED_DIRECTORIES = { - "build", "buck-out", "dist", "_build", ".git", ".hg", ".mypy_cache", ".tox", ".venv" + "build", + "buck-out", + "dist", + "_build", + ".git", + ".hg", + ".mypy_cache", + ".tox", + ".venv", } @@ -2717,9 +2835,9 @@ def assert_equivalent(src: str, dst: str) -> None: ) from None -def assert_stable(src: str, dst: str, line_length: int) -> None: +def assert_stable(src: str, dst: str, line_length: int, is_pyi: bool = False) -> None: """Raise AssertionError if `dst` reformats differently the second time.""" - newdst = format_str(dst, line_length=line_length) + newdst = format_str(dst, line_length=line_length, is_pyi=is_pyi) if dst != newdst: log = dump_to_file( diff(src, dst, "source", "first pass"), @@ -2758,7 +2876,7 @@ def diff(a: str, b: str, a_name: str, b_name: str) -> str: ) -def cancel(tasks: List[asyncio.Task]) -> None: +def cancel(tasks: Iterable[asyncio.Task]) -> None: """asyncio signal handler that cancels all `tasks` and reports to stderr.""" err("Aborted!") for task in tasks: @@ -2804,6 +2922,32 @@ def enumerate_reversed(sequence: Sequence[T]) -> Iterator[Tuple[Index, T]]: index -= 1 +def enumerate_with_length( + line: Line, reversed: bool = False +) -> Iterator[Tuple[Index, Leaf, int]]: + """Return an enumeration of leaves with their length. + + Stops prematurely on multiline strings and standalone comments. + """ + op = cast( + Callable[[Sequence[Leaf]], Iterator[Tuple[Index, Leaf]]], + enumerate_reversed if reversed else enumerate, + ) + for index, leaf in op(line.leaves): + length = len(leaf.prefix) + len(leaf.value) + if "\n" in leaf.value: + return # Multiline strings, we can't continue. + + comment: Optional[Leaf] + for comment in line.comments_after(leaf, index): + if "\n" in comment.prefix: + return # Oops, standalone comment! + + length += len(comment.value) + + yield index, leaf, length + + def is_line_short_enough(line: Line, *, line_length: int, line_str: str = "") -> bool: """Return True if `line` is no longer than `line_length`. @@ -2818,6 +2962,95 @@ def is_line_short_enough(line: Line, *, line_length: int, line_str: str = "") -> ) +def can_omit_invisible_parens(line: Line, line_length: int) -> bool: + """Does `line` have a shape safe to reformat without optional parens around it? + + Returns True for only a subset of potentially nice looking formattings but + the point is to not return false positives that end up producing lines that + are too long. + """ + bt = line.bracket_tracker + if not bt.delimiters: + # Without delimiters the optional parentheses are useless. + return True + + max_priority = bt.max_delimiter_priority() + if bt.delimiter_count_with_priority(max_priority) > 1: + # With more than one delimiter of a kind the optional parentheses read better. + return False + + if max_priority == DOT_PRIORITY: + # A single stranded method call doesn't require optional parentheses. + return True + + assert len(line.leaves) >= 2, "Stranded delimiter" + + first = line.leaves[0] + second = line.leaves[1] + penultimate = line.leaves[-2] + last = line.leaves[-1] + + # With a single delimiter, omit if the expression starts or ends with + # a bracket. + if first.type in OPENING_BRACKETS and second.type not in CLOSING_BRACKETS: + remainder = False + length = 4 * line.depth + for _index, leaf, leaf_length in enumerate_with_length(line): + if leaf.type in CLOSING_BRACKETS and leaf.opening_bracket is first: + remainder = True + if remainder: + length += leaf_length + if length > line_length: + break + + if leaf.type in OPENING_BRACKETS: + # There are brackets we can further split on. + remainder = False + + else: + # checked the entire string and line length wasn't exceeded + if len(line.leaves) == _index + 1: + return True + + # Note: we are not returning False here because a line might have *both* + # a leading opening bracket and a trailing closing bracket. If the + # opening bracket doesn't match our rule, maybe the closing will. + + if ( + last.type == token.RPAR + or last.type == token.RBRACE + or ( + # don't use indexing for omitting optional parentheses; + # it looks weird + last.type == token.RSQB + and last.parent + and last.parent.type != syms.trailer + ) + ): + if penultimate.type in OPENING_BRACKETS: + # Empty brackets don't help. + return False + + if is_multiline_string(first): + # Additional wrapping of a multiline string in this situation is + # unnecessary. + return True + + length = 4 * line.depth + seen_other_brackets = False + for _index, leaf, leaf_length in enumerate_with_length(line): + length += leaf_length + if leaf is last.opening_bracket: + if seen_other_brackets or length <= line_length: + return True + + elif leaf.type in OPENING_BRACKETS: + # There are brackets we can further split on. + seen_other_brackets = True + + return False + + CACHE_DIR = Path(user_cache_dir("black", version=__version__))