--- /dev/null
+"""
+Generating lines of code.
+"""
+from functools import partial, wraps
+import sys
+from typing import Collection, Iterator, List, Optional, Set, Union
+
+from dataclasses import dataclass, field
+
+from black.nodes import WHITESPACE, RARROW, STATEMENT, STANDALONE_COMMENT
+from black.nodes import ASSIGNMENTS, OPENING_BRACKETS, CLOSING_BRACKETS
+from black.nodes import Visitor, syms, first_child_is_arith, ensure_visible
+from black.nodes import is_docstring, is_empty_tuple, is_one_tuple, is_one_tuple_between
+from black.nodes import is_walrus_assignment, is_yield, is_vararg, is_multiline_string
+from black.nodes import is_stub_suite, is_stub_body, is_atom_with_invisible_parens
+from black.nodes import wrap_in_parentheses
+from black.brackets import max_delimiter_priority_in_atom
+from black.brackets import DOT_PRIORITY, COMMA_PRIORITY
+from black.lines import Line, line_to_string, is_line_short_enough
+from black.lines import can_omit_invisible_parens, can_be_split, append_leaves
+from black.comments import generate_comments, list_comments, FMT_OFF
+from black.numerics import normalize_numeric_literal
+from black.strings import get_string_prefix, fix_docstring
+from black.strings import normalize_string_prefix, normalize_string_quotes
+from black.trans import Transformer, CannotTransform, StringMerger
+from black.trans import StringSplitter, StringParenWrapper, StringParenStripper
+from black.mode import Mode
+from black.mode import Feature
+
+from blib2to3.pytree import Node, Leaf
+from blib2to3.pgen2 import token
+
+
+# types
+LeafID = int
+LN = Union[Leaf, Node]
+
+
+class CannotSplit(CannotTransform):
+ """A readable split that fits the allotted line length is impossible."""
+
+
+@dataclass
+class LineGenerator(Visitor[Line]):
+ """Generates reformatted Line objects. Empty lines are not emitted.
+
+ 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.
+ """
+
+ mode: Mode
+ remove_u_prefix: bool = False
+ current_line: Line = field(init=False)
+
+ def line(self, indent: int = 0) -> Iterator[Line]:
+ """Generate a line.
+
+ If the line is empty, only emit if it makes sense.
+ If the line is too long, split it first and then generate.
+
+ If any lines were generated, set up a new current_line.
+ """
+ if not self.current_line:
+ 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(mode=self.mode, depth=complete_line.depth + indent)
+ yield complete_line
+
+ 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 self.mode.string_normalization and node.type == token.STRING:
+ node.value = normalize_string_prefix(
+ node.value, remove_u_prefix=self.remove_u_prefix
+ )
+ node.value = normalize_string_quotes(node.value)
+ if node.type == token.NUMBER:
+ normalize_numeric_literal(node)
+ if node.type not in WHITESPACE:
+ self.current_line.append(node)
+ yield from super().visit_default(node)
+
+ def visit_INDENT(self, node: Leaf) -> 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: Leaf) -> Iterator[Line]:
+ """Decrease indentation level, maybe yield a line."""
+ # The current line might still wait for trailing comments. At DEDENT time
+ # there won't be any (they would be prefixes on the preceding NEWLINE).
+ # Emit the line then.
+ yield from self.line()
+
+ # While DEDENT has no value, its prefix may contain standalone comments
+ # that belong to the current indentation level. Get 'em.
+ yield from self.visit_default(node)
+
+ # Finally, emit the dedent.
+ yield from self.line(-1)
+
+ def visit_stmt(
+ self, node: Node, keywords: Set[str], parens: Set[str]
+ ) -> Iterator[Line]:
+ """Visit a statement.
+
+ This implementation is shared for `if`, `while`, `for`, `try`, `except`,
+ `def`, `with`, `class`, `assert` and assignments.
+
+ 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 immediately after which
+ invisible parens should be put.
+ """
+ normalize_invisible_parens(node, parens_after=parens)
+ for child in node.children:
+ if child.type == token.NAME and child.value in keywords: # type: ignore
+ yield from self.line()
+
+ yield from self.visit(child)
+
+ def visit_suite(self, node: Node) -> Iterator[Line]:
+ """Visit a suite."""
+ if self.mode.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."""
+ if first_child_is_arith(node):
+ wrap_in_parentheses(node, node.children[0], visible=False)
+ is_suite_like = node.parent and node.parent.type in STATEMENT
+ if is_suite_like:
+ if self.mode.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:
+ if (
+ not self.mode.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]:
+ """Visit `async def`, `async for`, `async with`."""
+ yield from self.line()
+
+ children = iter(node.children)
+ for child in children:
+ yield from self.visit(child)
+
+ if child.type == token.ASYNC:
+ break
+
+ internal_stmt = next(children)
+ for child in internal_stmt.children:
+ 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_STANDALONE_COMMENT(self, leaf: Leaf) -> Iterator[Line]:
+ if not self.current_line.bracket_tracker.any_open_brackets():
+ yield from self.line()
+ yield from self.visit_default(leaf)
+
+ def visit_factor(self, node: Node) -> Iterator[Line]:
+ """Force parentheses between a unary op and a binary power:
+
+ -2 ** 8 -> -(2 ** 8)
+ """
+ _operator, operand = node.children
+ if (
+ operand.type == syms.power
+ and len(operand.children) == 3
+ and operand.children[1].type == token.DOUBLESTAR
+ ):
+ lpar = Leaf(token.LPAR, "(")
+ rpar = Leaf(token.RPAR, ")")
+ index = operand.remove() or 0
+ node.insert_child(index, Node(syms.atom, [lpar, operand, rpar]))
+ yield from self.visit_default(node)
+
+ def visit_STRING(self, leaf: Leaf) -> Iterator[Line]:
+ if is_docstring(leaf) and "\\\n" not in leaf.value:
+ # We're ignoring docstrings with backslash newline escapes because changing
+ # indentation of those changes the AST representation of the code.
+ docstring = normalize_string_prefix(leaf.value, self.remove_u_prefix)
+ prefix = get_string_prefix(docstring)
+ docstring = docstring[len(prefix) :] # Remove the prefix
+ quote_char = docstring[0]
+ # A natural way to remove the outer quotes is to do:
+ # docstring = docstring.strip(quote_char)
+ # but that breaks on """""x""" (which is '""x').
+ # So we actually need to remove the first character and the next two
+ # characters but only if they are the same as the first.
+ quote_len = 1 if docstring[1] != quote_char else 3
+ docstring = docstring[quote_len:-quote_len]
+ docstring_started_empty = not docstring
+
+ if is_multiline_string(leaf):
+ indent = " " * 4 * self.current_line.depth
+ docstring = fix_docstring(docstring, indent)
+ else:
+ docstring = docstring.strip()
+
+ if docstring:
+ # Add some padding if the docstring starts / ends with a quote mark.
+ if docstring[0] == quote_char:
+ docstring = " " + docstring
+ if docstring[-1] == quote_char:
+ docstring += " "
+ if docstring[-1] == "\\":
+ backslash_count = len(docstring) - len(docstring.rstrip("\\"))
+ if backslash_count % 2:
+ # Odd number of tailing backslashes, add some padding to
+ # avoid escaping the closing string quote.
+ docstring += " "
+ elif not docstring_started_empty:
+ docstring = " "
+
+ # We could enforce triple quotes at this point.
+ quote = quote_char * quote_len
+ leaf.value = prefix + quote + docstring + quote
+
+ yield from self.visit_default(leaf)
+
+ def __post_init__(self) -> None:
+ """You are in a twisty little maze of passages."""
+ self.current_line = Line(mode=self.mode)
+
+ v = self.visit_stmt
+ Ø: Set[str] = set()
+ self.visit_assert_stmt = partial(v, keywords={"assert"}, parens={"assert", ","})
+ self.visit_if_stmt = partial(
+ v, keywords={"if", "else", "elif"}, parens={"if", "elif"}
+ )
+ self.visit_while_stmt = partial(v, keywords={"while", "else"}, parens={"while"})
+ self.visit_for_stmt = partial(v, keywords={"for", "else"}, parens={"for", "in"})
+ self.visit_try_stmt = partial(
+ v, keywords={"try", "except", "else", "finally"}, parens=Ø
+ )
+ self.visit_except_clause = partial(v, keywords={"except"}, parens=Ø)
+ self.visit_with_stmt = partial(v, keywords={"with"}, parens=Ø)
+ self.visit_funcdef = partial(v, keywords={"def"}, parens=Ø)
+ self.visit_classdef = partial(v, keywords={"class"}, parens=Ø)
+ self.visit_expr_stmt = partial(v, keywords=Ø, parens=ASSIGNMENTS)
+ self.visit_return_stmt = partial(v, keywords={"return"}, parens={"return"})
+ self.visit_import_from = partial(v, keywords=Ø, parens={"import"})
+ self.visit_del_stmt = partial(v, keywords=Ø, parens={"del"})
+ self.visit_async_funcdef = self.visit_async_stmt
+ self.visit_decorated = self.visit_decorators
+
+
+def transform_line(
+ line: Line, mode: Mode, features: Collection[Feature] = ()
+) -> Iterator[Line]:
+ """Transform a `line`, potentially splitting it into many lines.
+
+ They should fit in the allotted `line_length` but might not be able to.
+
+ `features` are syntactical features that may be used in the output.
+ """
+ if line.is_comment:
+ yield line
+ return
+
+ line_str = line_to_string(line)
+
+ ll = mode.line_length
+ sn = mode.string_normalization
+ string_merge = StringMerger(ll, sn)
+ string_paren_strip = StringParenStripper(ll, sn)
+ string_split = StringSplitter(ll, sn)
+ string_paren_wrap = StringParenWrapper(ll, sn)
+
+ transformers: List[Transformer]
+ if (
+ not line.contains_uncollapsable_type_comments()
+ and not line.should_split_rhs
+ and not line.magic_trailing_comma
+ and (
+ is_line_short_enough(line, line_length=mode.line_length, line_str=line_str)
+ or line.contains_unsplittable_type_ignore()
+ )
+ and not (line.inside_brackets and line.contains_standalone_comments())
+ ):
+ # Only apply basic string preprocessing, since lines shouldn't be split here.
+ if mode.experimental_string_processing:
+ transformers = [string_merge, string_paren_strip]
+ else:
+ transformers = []
+ elif line.is_def:
+ transformers = [left_hand_split]
+ else:
+
+ def rhs(line: Line, features: Collection[Feature]) -> Iterator[Line]:
+ """Wraps calls to `right_hand_split`.
+
+ The calls increasingly `omit` right-hand trailers (bracket pairs with
+ content), meaning the trailers get glued together to split on another
+ bracket pair instead.
+ """
+ for omit in generate_trailers_to_omit(line, mode.line_length):
+ lines = list(
+ right_hand_split(line, mode.line_length, features, omit=omit)
+ )
+ # Note: this check is only able to figure out if the first line of the
+ # *current* transformation fits in the line length. This is true only
+ # for simple cases. All others require running more transforms via
+ # `transform_line()`. This check doesn't know if those would succeed.
+ if is_line_short_enough(lines[0], line_length=mode.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, as well as lines that contain
+ # trailing commas (those have to be exploded).
+ yield from right_hand_split(
+ line, line_length=mode.line_length, features=features
+ )
+
+ if mode.experimental_string_processing:
+ if line.inside_brackets:
+ transformers = [
+ string_merge,
+ string_paren_strip,
+ string_split,
+ delimiter_split,
+ standalone_comment_split,
+ string_paren_wrap,
+ rhs,
+ ]
+ else:
+ transformers = [
+ string_merge,
+ string_paren_strip,
+ string_split,
+ string_paren_wrap,
+ rhs,
+ ]
+ else:
+ if line.inside_brackets:
+ transformers = [delimiter_split, standalone_comment_split, rhs]
+ else:
+ transformers = [rhs]
+
+ for transform in transformers:
+ # We are accumulating lines in `result` because we might want to abort
+ # mission and return the original line in the end, or attempt a different
+ # split altogether.
+ try:
+ result = run_transformer(line, transform, mode, features, line_str=line_str)
+ except CannotTransform:
+ continue
+ else:
+ yield from result
+ break
+
+ else:
+ yield line
+
+
+def left_hand_split(line: Line, _features: Collection[Feature] = ()) -> Iterator[Line]:
+ """Split 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. This is why this function is not symmetrical with
+ :func:`right_hand_split` which also handles optional parentheses.
+ """
+ tail_leaves: List[Leaf] = []
+ body_leaves: List[Leaf] = []
+ head_leaves: List[Leaf] = []
+ current_leaves = head_leaves
+ matching_bracket: Optional[Leaf] = None
+ for leaf in line.leaves:
+ if (
+ current_leaves is body_leaves
+ and leaf.type in CLOSING_BRACKETS
+ and leaf.opening_bracket is matching_bracket
+ ):
+ current_leaves = tail_leaves if body_leaves else head_leaves
+ current_leaves.append(leaf)
+ if current_leaves is head_leaves:
+ if leaf.type in OPENING_BRACKETS:
+ matching_bracket = leaf
+ current_leaves = body_leaves
+ if not matching_bracket:
+ raise CannotSplit("No brackets found")
+
+ head = bracket_split_build_line(head_leaves, line, matching_bracket)
+ body = bracket_split_build_line(body_leaves, line, matching_bracket, is_body=True)
+ tail = bracket_split_build_line(tail_leaves, line, matching_bracket)
+ bracket_split_succeeded_or_raise(head, body, tail)
+ for result in (head, body, tail):
+ if result:
+ yield result
+
+
+def right_hand_split(
+ line: Line,
+ line_length: int,
+ features: Collection[Feature] = (),
+ 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`.
+ """
+ tail_leaves: List[Leaf] = []
+ body_leaves: List[Leaf] = []
+ head_leaves: List[Leaf] = []
+ current_leaves = tail_leaves
+ opening_bracket: Optional[Leaf] = None
+ closing_bracket: Optional[Leaf] = None
+ for leaf in reversed(line.leaves):
+ if current_leaves is body_leaves:
+ if leaf is opening_bracket:
+ current_leaves = head_leaves if body_leaves else tail_leaves
+ current_leaves.append(leaf)
+ if current_leaves is tail_leaves:
+ if leaf.type in CLOSING_BRACKETS and id(leaf) not in omit:
+ opening_bracket = leaf.opening_bracket
+ closing_bracket = leaf
+ current_leaves = body_leaves
+ if not (opening_bracket and closing_bracket and head_leaves):
+ # If there is no opening or closing_bracket that means the split failed and
+ # all content is in the tail. Otherwise, if `head_leaves` are empty, it means
+ # the matching `opening_bracket` wasn't available on `line` anymore.
+ raise CannotSplit("No brackets found")
+
+ tail_leaves.reverse()
+ body_leaves.reverse()
+ head_leaves.reverse()
+ head = bracket_split_build_line(head_leaves, line, opening_bracket)
+ body = bracket_split_build_line(body_leaves, line, opening_bracket, is_body=True)
+ tail = bracket_split_build_line(tail_leaves, line, opening_bracket)
+ bracket_split_succeeded_or_raise(head, body, tail)
+ if (
+ Feature.FORCE_OPTIONAL_PARENTHESES not in features
+ # the opening bracket is an optional paren
+ and opening_bracket.type == token.LPAR
+ and not opening_bracket.value
+ # the closing bracket is an optional paren
+ and closing_bracket.type == token.RPAR
+ and not closing_bracket.value
+ # 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
+ # there are no standalone comments in the body
+ and not body.contains_standalone_comments(0)
+ # and we can actually remove the parens
+ and can_omit_invisible_parens(body, line_length, omit_on_explode=omit)
+ ):
+ omit = {id(closing_bracket), *omit}
+ try:
+ yield from right_hand_split(line, line_length, features=features, omit=omit)
+ return
+
+ except CannotSplit as e:
+ if not (
+ can_be_split(body)
+ or is_line_short_enough(body, line_length=line_length)
+ ):
+ raise CannotSplit(
+ "Splitting failed, body is still too long and can't be split."
+ ) from e
+
+ elif head.contains_multiline_strings() or tail.contains_multiline_strings():
+ raise CannotSplit(
+ "The current optional pair of parentheses is bound to fail to"
+ " satisfy the splitting algorithm because the head or the tail"
+ " contains multiline strings which by definition never fit one"
+ " line."
+ ) from e
+
+ ensure_visible(opening_bracket)
+ ensure_visible(closing_bracket)
+ for result in (head, body, tail):
+ if result:
+ yield result
+
+
+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:
+ raise CannotSplit("Splitting brackets produced the same line")
+
+ elif tail_len < 3:
+ raise CannotSplit(
+ f"Splitting brackets on an empty body to save {tail_len} characters is"
+ " not worth it"
+ )
+
+
+def bracket_split_build_line(
+ leaves: List[Leaf], original: Line, opening_bracket: Leaf, *, is_body: bool = False
+) -> Line:
+ """Return a new line with given `leaves` and respective comments from `original`.
+
+ If `is_body` is True, the result line is one-indented inside brackets and as such
+ has its first leaf's prefix normalized and a trailing comma added when expected.
+ """
+ result = Line(mode=original.mode, depth=original.depth)
+ if is_body:
+ result.inside_brackets = True
+ result.depth += 1
+ if leaves:
+ # Since body is a new indent level, remove spurious leading whitespace.
+ normalize_prefix(leaves[0], inside_brackets=True)
+ # Ensure a trailing comma for imports and standalone function arguments, but
+ # be careful not to add one after any comments or within type annotations.
+ no_commas = (
+ original.is_def
+ and opening_bracket.value == "("
+ and not any(leaf.type == token.COMMA for leaf in leaves)
+ # In particular, don't add one within a parenthesized return annotation.
+ # Unfortunately the indicator we're in a return annotation (RARROW) may
+ # be defined directly in the parent node, the parent of the parent ...
+ # and so on depending on how complex the return annotation is.
+ # This isn't perfect and there's some false negatives but they are in
+ # contexts were a comma is actually fine.
+ and not any(
+ node.prev_sibling.type == RARROW
+ for node in (
+ leaves[0].parent,
+ getattr(leaves[0].parent, "parent", None),
+ )
+ if isinstance(node, Node) and isinstance(node.prev_sibling, Leaf)
+ )
+ )
+
+ if original.is_import or no_commas:
+ for i in range(len(leaves) - 1, -1, -1):
+ if leaves[i].type == STANDALONE_COMMENT:
+ continue
+
+ if leaves[i].type != token.COMMA:
+ new_comma = Leaf(token.COMMA, ",")
+ leaves.insert(i + 1, new_comma)
+ break
+
+ # Populate the line
+ for leaf in leaves:
+ result.append(leaf, preformatted=True)
+ for comment_after in original.comments_after(leaf):
+ result.append(comment_after, preformatted=True)
+ if is_body and should_split_line(result, opening_bracket):
+ result.should_split_rhs = True
+ return result
+
+
+def dont_increase_indentation(split_func: Transformer) -> Transformer:
+ """Normalize prefix of the first leaf in every line returned by `split_func`.
+
+ This is a decorator over relevant split functions.
+ """
+
+ @wraps(split_func)
+ def split_wrapper(line: Line, features: Collection[Feature] = ()) -> Iterator[Line]:
+ for line in split_func(line, features):
+ normalize_prefix(line.leaves[0], inside_brackets=True)
+ yield line
+
+ return split_wrapper
+
+
+@dont_increase_indentation
+def delimiter_split(line: Line, features: Collection[Feature] = ()) -> Iterator[Line]:
+ """Split according to delimiters of the highest priority.
+
+ If the appropriate Features are given, the split will add trailing commas
+ also in function signatures and calls that contain `*` and `**`.
+ """
+ try:
+ last_leaf = line.leaves[-1]
+ except IndexError:
+ raise CannotSplit("Line empty") from None
+
+ bt = line.bracket_tracker
+ try:
+ delimiter_priority = bt.max_delimiter_priority(exclude={id(last_leaf)})
+ except ValueError:
+ raise CannotSplit("No delimiters found") from None
+
+ 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(
+ mode=line.mode, depth=line.depth, inside_brackets=line.inside_brackets
+ )
+ lowest_depth = sys.maxsize
+ trailing_comma_safe = True
+
+ def append_to_line(leaf: Leaf) -> Iterator[Line]:
+ """Append `leaf` to current line or to new line if appending impossible."""
+ nonlocal current_line
+ try:
+ current_line.append_safe(leaf, preformatted=True)
+ except ValueError:
+ yield current_line
+
+ current_line = Line(
+ mode=line.mode, depth=line.depth, inside_brackets=line.inside_brackets
+ )
+ current_line.append(leaf)
+
+ for leaf in line.leaves:
+ yield from append_to_line(leaf)
+
+ for comment_after in line.comments_after(leaf):
+ yield from append_to_line(comment_after)
+
+ lowest_depth = min(lowest_depth, leaf.bracket_depth)
+ if leaf.bracket_depth == lowest_depth:
+ if is_vararg(leaf, within={syms.typedargslist}):
+ trailing_comma_safe = (
+ trailing_comma_safe and Feature.TRAILING_COMMA_IN_DEF in features
+ )
+ elif is_vararg(leaf, within={syms.arglist, syms.argument}):
+ trailing_comma_safe = (
+ trailing_comma_safe and Feature.TRAILING_COMMA_IN_CALL in features
+ )
+
+ leaf_priority = bt.delimiters.get(id(leaf))
+ if leaf_priority == delimiter_priority:
+ yield current_line
+
+ current_line = Line(
+ mode=line.mode, depth=line.depth, inside_brackets=line.inside_brackets
+ )
+ if current_line:
+ if (
+ trailing_comma_safe
+ and delimiter_priority == COMMA_PRIORITY
+ and current_line.leaves[-1].type != token.COMMA
+ and current_line.leaves[-1].type != STANDALONE_COMMENT
+ ):
+ new_comma = Leaf(token.COMMA, ",")
+ current_line.append(new_comma)
+ yield current_line
+
+
+@dont_increase_indentation
+def standalone_comment_split(
+ line: Line, features: Collection[Feature] = ()
+) -> Iterator[Line]:
+ """Split standalone comments from the rest of the line."""
+ if not line.contains_standalone_comments(0):
+ raise CannotSplit("Line does not have any standalone comments")
+
+ current_line = Line(
+ mode=line.mode, depth=line.depth, inside_brackets=line.inside_brackets
+ )
+
+ def append_to_line(leaf: Leaf) -> Iterator[Line]:
+ """Append `leaf` to current line or to new line if appending impossible."""
+ nonlocal current_line
+ try:
+ current_line.append_safe(leaf, preformatted=True)
+ except ValueError:
+ yield current_line
+
+ current_line = Line(
+ line.mode, depth=line.depth, inside_brackets=line.inside_brackets
+ )
+ current_line.append(leaf)
+
+ for leaf in line.leaves:
+ yield from append_to_line(leaf)
+
+ for comment_after in line.comments_after(leaf):
+ yield from append_to_line(comment_after)
+
+ if current_line:
+ yield current_line
+
+
+def normalize_prefix(leaf: Leaf, *, inside_brackets: bool) -> None:
+ """Leave existing extra newlines if not `inside_brackets`. Remove everything
+ else.
+
+ Note: don't use backslashes for formatting or you'll lose your voting rights.
+ """
+ if not inside_brackets:
+ spl = leaf.prefix.split("#")
+ if "\\" not in spl[0]:
+ nl_count = spl[-1].count("\n")
+ if len(spl) > 1:
+ nl_count -= 1
+ leaf.prefix = "\n" * nl_count
+ return
+
+ leaf.prefix = ""
+
+
+def normalize_invisible_parens(node: Node, parens_after: Set[str]) -> None:
+ """Make existing optional parentheses invisible or create new ones.
+
+ `parens_after` is a set of string leaf values immediately after which parens
+ should be put.
+
+ Standardizes on visible parentheses for single-element tuples, and keeps
+ existing visible parentheses for other tuples and generator expressions.
+ """
+ for pc in list_comments(node.prefix, is_endmarker=False):
+ if pc.value in FMT_OFF:
+ # This `node` has a prefix with `# fmt: off`, don't mess with parens.
+ return
+ check_lpar = False
+ for index, child in enumerate(list(node.children)):
+ # Fixes a bug where invisible parens are not properly stripped from
+ # assignment statements that contain type annotations.
+ if isinstance(child, Node) and child.type == syms.annassign:
+ normalize_invisible_parens(child, parens_after=parens_after)
+
+ # Add parentheses around long tuple unpacking in assignments.
+ if (
+ index == 0
+ and isinstance(child, Node)
+ and child.type == syms.testlist_star_expr
+ ):
+ check_lpar = True
+
+ if check_lpar:
+ if child.type == syms.atom:
+ if maybe_make_parens_invisible_in_atom(child, parent=node):
+ wrap_in_parentheses(node, child, visible=False)
+ elif is_one_tuple(child):
+ wrap_in_parentheses(node, child, visible=True)
+ elif node.type == syms.import_from:
+ # "import from" nodes store parentheses directly as part of
+ # the statement
+ if child.type == token.LPAR:
+ # make parentheses invisible
+ child.value = "" # type: ignore
+ node.children[-1].value = "" # type: ignore
+ elif child.type != token.STAR:
+ # insert invisible parentheses
+ node.insert_child(index, Leaf(token.LPAR, ""))
+ node.append_child(Leaf(token.RPAR, ""))
+ break
+
+ elif not (isinstance(child, Leaf) and is_multiline_string(child)):
+ wrap_in_parentheses(node, child, visible=False)
+
+ check_lpar = isinstance(child, Leaf) and child.value in parens_after
+
+
+def maybe_make_parens_invisible_in_atom(node: LN, parent: LN) -> bool:
+ """If it's safe, make the parens in the atom `node` invisible, recursively.
+ Additionally, remove repeated, adjacent invisible parens from the atom `node`
+ as they are redundant.
+
+ Returns whether the node should itself be wrapped in invisible parentheses.
+
+ """
+
+ if (
+ node.type != syms.atom
+ or is_empty_tuple(node)
+ or is_one_tuple(node)
+ or (is_yield(node) and parent.type != syms.expr_stmt)
+ or max_delimiter_priority_in_atom(node) >= COMMA_PRIORITY
+ ):
+ return False
+
+ if is_walrus_assignment(node):
+ if parent.type in [
+ syms.annassign,
+ syms.expr_stmt,
+ syms.assert_stmt,
+ syms.return_stmt,
+ # these ones aren't useful to end users, but they do please fuzzers
+ syms.for_stmt,
+ syms.del_stmt,
+ ]:
+ return False
+
+ first = node.children[0]
+ last = node.children[-1]
+ if first.type == token.LPAR and last.type == token.RPAR:
+ middle = node.children[1]
+ # make parentheses invisible
+ first.value = "" # type: ignore
+ last.value = "" # type: ignore
+ maybe_make_parens_invisible_in_atom(middle, parent=parent)
+
+ if is_atom_with_invisible_parens(middle):
+ # Strip the invisible parens from `middle` by replacing
+ # it with the child in-between the invisible parens
+ middle.replace(middle.children[1])
+
+ return False
+
+ return True
+
+
+def should_split_line(line: Line, opening_bracket: Leaf) -> bool:
+ """Should `line` be immediately split with `delimiter_split()` after RHS?"""
+
+ if not (opening_bracket.parent and opening_bracket.value in "[{("):
+ return False
+
+ # We're essentially checking if the body is delimited by commas and there's more
+ # than one of them (we're excluding the trailing comma and if the delimiter priority
+ # is still commas, that means there's more).
+ exclude = set()
+ trailing_comma = False
+ try:
+ last_leaf = line.leaves[-1]
+ if last_leaf.type == token.COMMA:
+ trailing_comma = True
+ exclude.add(id(last_leaf))
+ max_priority = line.bracket_tracker.max_delimiter_priority(exclude=exclude)
+ except (IndexError, ValueError):
+ return False
+
+ return max_priority == COMMA_PRIORITY and (
+ (line.mode.magic_trailing_comma and trailing_comma)
+ # always explode imports
+ or opening_bracket.parent.type in {syms.atom, syms.import_from}
+ )
+
+
+def generate_trailers_to_omit(line: Line, line_length: int) -> Iterator[Set[LeafID]]:
+ """Generate sets of closing bracket IDs that should be omitted in a RHS.
+
+ Brackets can be omitted if the entire trailer up to and including
+ a preceding closing bracket fits in one line.
+
+ Yielded sets are cumulative (contain results of previous yields, too). First
+ set is empty, unless the line should explode, in which case bracket pairs until
+ the one that needs to explode are omitted.
+ """
+
+ omit: Set[LeafID] = set()
+ if not line.magic_trailing_comma:
+ yield omit
+
+ length = 4 * line.depth
+ opening_bracket: Optional[Leaf] = None
+ closing_bracket: Optional[Leaf] = None
+ inner_brackets: Set[LeafID] = set()
+ for index, leaf, leaf_length in line.enumerate_with_length(reversed=True):
+ length += leaf_length
+ if length > line_length:
+ break
+
+ has_inline_comment = leaf_length > len(leaf.value) + len(leaf.prefix)
+ if leaf.type == STANDALONE_COMMENT or has_inline_comment:
+ break
+
+ if opening_bracket:
+ if leaf is opening_bracket:
+ opening_bracket = None
+ elif leaf.type in CLOSING_BRACKETS:
+ prev = line.leaves[index - 1] if index > 0 else None
+ if (
+ prev
+ and prev.type == token.COMMA
+ and not is_one_tuple_between(
+ leaf.opening_bracket, leaf, line.leaves
+ )
+ ):
+ # Never omit bracket pairs with trailing commas.
+ # We need to explode on those.
+ break
+
+ inner_brackets.add(id(leaf))
+ elif leaf.type in CLOSING_BRACKETS:
+ prev = line.leaves[index - 1] if index > 0 else None
+ if prev and prev.type in OPENING_BRACKETS:
+ # Empty brackets would fail a split so treat them as "inner"
+ # brackets (e.g. only add them to the `omit` set if another
+ # pair of brackets was good enough.
+ inner_brackets.add(id(leaf))
+ continue
+
+ if closing_bracket:
+ omit.add(id(closing_bracket))
+ omit.update(inner_brackets)
+ inner_brackets.clear()
+ yield omit
+
+ if (
+ prev
+ and prev.type == token.COMMA
+ and not is_one_tuple_between(leaf.opening_bracket, leaf, line.leaves)
+ ):
+ # Never omit bracket pairs with trailing commas.
+ # We need to explode on those.
+ break
+
+ if leaf.value:
+ opening_bracket = leaf.opening_bracket
+ closing_bracket = leaf
+
+
+def run_transformer(
+ line: Line,
+ transform: Transformer,
+ mode: Mode,
+ features: Collection[Feature],
+ *,
+ line_str: str = "",
+) -> List[Line]:
+ if not line_str:
+ line_str = line_to_string(line)
+ result: List[Line] = []
+ for transformed_line in transform(line, features):
+ if str(transformed_line).strip("\n") == line_str:
+ raise CannotTransform("Line transformer returned an unchanged result")
+
+ result.extend(transform_line(transformed_line, mode=mode, features=features))
+
+ if (
+ transform.__name__ != "rhs"
+ or not line.bracket_tracker.invisible
+ or any(bracket.value for bracket in line.bracket_tracker.invisible)
+ or line.contains_multiline_strings()
+ or result[0].contains_uncollapsable_type_comments()
+ or result[0].contains_unsplittable_type_ignore()
+ or is_line_short_enough(result[0], line_length=mode.line_length)
+ # If any leaves have no parents (which _can_ occur since
+ # `transform(line)` potentially destroys the line's underlying node
+ # structure), then we can't proceed. Doing so would cause the below
+ # call to `append_leaves()` to fail.
+ or any(leaf.parent is None for leaf in line.leaves)
+ ):
+ return result
+
+ line_copy = line.clone()
+ append_leaves(line_copy, line, line.leaves)
+ features_fop = set(features) | {Feature.FORCE_OPTIONAL_PARENTHESES}
+ second_opinion = run_transformer(
+ line_copy, transform, mode, features_fop, line_str=line_str
+ )
+ if all(
+ is_line_short_enough(ln, line_length=mode.line_length) for ln in second_opinion
+ ):
+ result = second_opinion
+ return result
projects / etc / vim.git / blobdiff