import itertools
+import math
import sys
from dataclasses import dataclass, field
from typing import (
Sequence,
Tuple,
TypeVar,
+ Union,
cast,
)
-from black.brackets import DOT_PRIORITY, BracketTracker
+from black.brackets import COMMA_PRIORITY, DOT_PRIORITY, BracketTracker
from black.mode import Mode, Preview
from black.nodes import (
BRACKETS,
is_multiline_string,
is_one_sequence_between,
is_type_comment,
+ is_type_ignore_comment,
+ is_with_or_async_with_stmt,
replace_child,
syms,
whitespace,
)
+from black.strings import str_width
from blib2to3.pgen2 import token
from blib2to3.pytree import Leaf, Node
T = TypeVar("T")
Index = int
LeafID = int
+LN = Union[Leaf, Node]
@dataclass
class Line:
"""Holds leaves and comments. Can be printed with `str(line)`."""
- mode: Mode
+ mode: Mode = field(repr=False)
depth: int = 0
leaves: List[Leaf] = field(default_factory=list)
# keys ordered like `leaves`
# Note: at this point leaf.prefix should be empty except for
# imports, for which we only preserve newlines.
leaf.prefix += whitespace(
- leaf, complex_subscript=self.is_complex_subscript(leaf)
+ leaf,
+ complex_subscript=self.is_complex_subscript(leaf),
+ mode=self.mode,
)
if self.inside_brackets or not preformatted or track_bracket:
self.bracket_tracker.mark(leaf)
"""Is this an import line?"""
return bool(self) and is_import(self.leaves[0])
+ @property
+ def is_with_or_async_with_stmt(self) -> bool:
+ """Is this a with_stmt line?"""
+ return bool(self) and is_with_or_async_with_stmt(self.leaves[0])
+
@property
def is_class(self) -> bool:
"""Is this line a class definition?"""
and second_leaf.value == "def"
)
+ @property
+ def is_stub_def(self) -> bool:
+ """Is this line a function definition with a body consisting only of "..."?"""
+ return self.is_def and self.leaves[-4:] == [Leaf(token.COLON, ":")] + [
+ Leaf(token.DOT, ".") for _ in range(3)
+ ]
+
@property
def is_class_paren_empty(self) -> bool:
"""Is this a class with no base classes but using parentheses?
@property
def is_triple_quoted_string(self) -> bool:
"""Is the line a triple quoted string?"""
- return (
- bool(self)
- and self.leaves[0].type == token.STRING
- and self.leaves[0].value.startswith(('"""', "'''"))
- )
+ if not self or self.leaves[0].type != token.STRING:
+ return False
+ value = self.leaves[0].value
+ if value.startswith(('"""', "'''")):
+ return True
+ if Preview.accept_raw_docstrings in self.mode and value.startswith(
+ ("r'''", 'r"""', "R'''", 'R"""')
+ ):
+ return True
+ return False
@property
def opens_block(self) -> bool:
return False
return self.leaves[-1].type == token.COLON
+ def is_fmt_pass_converted(
+ self, *, first_leaf_matches: Optional[Callable[[Leaf], bool]] = None
+ ) -> bool:
+ """Is this line converted from fmt off/skip code?
+
+ If first_leaf_matches is not None, it only returns True if the first
+ leaf of converted code matches.
+ """
+ if len(self.leaves) != 1:
+ return False
+ leaf = self.leaves[0]
+ if (
+ leaf.type != STANDALONE_COMMENT
+ or leaf.fmt_pass_converted_first_leaf is None
+ ):
+ return False
+ return first_leaf_matches is None or first_leaf_matches(
+ leaf.fmt_pass_converted_first_leaf
+ )
+
def contains_standalone_comments(self, depth_limit: int = sys.maxsize) -> bool:
"""If so, needs to be split before emitting."""
for leaf in self.leaves:
for comment in comments:
if is_type_comment(comment):
if comment_seen or (
- not is_type_comment(comment, " ignore")
+ not is_type_ignore_comment(comment)
and leaf_id not in ignored_ids
):
return True
# line.
for node in self.leaves[-2:]:
for comment in self.comments.get(id(node), []):
- if is_type_comment(comment, " ignore"):
+ if is_type_ignore_comment(comment):
return True
return False
- it's not a single-element subscript
Additionally, if ensure_removable:
- it's not from square bracket indexing
- (specifically, single-element square bracket indexing with
- Preview.skip_magic_trailing_comma_in_subscript)
+ (specifically, single-element square bracket indexing)
"""
if not (
closing.type in CLOSING_BRACKETS
if closing.type == token.RSQB:
if (
- Preview.one_element_subscript in self.mode
- and closing.parent
+ closing.parent
and closing.parent.type == syms.trailer
and closing.opening_bracket
and is_one_sequence_between(
comma = self.leaves[-1]
if comma.parent is None:
return False
- if Preview.skip_magic_trailing_comma_in_subscript in self.mode:
- return (
- comma.parent.type != syms.subscriptlist
- or closing.opening_bracket is None
- or not is_one_sequence_between(
- closing.opening_bracket,
- closing,
- self.leaves,
- brackets=(token.LSQB, token.RSQB),
- )
+ return (
+ comma.parent.type != syms.subscriptlist
+ or closing.opening_bracket is None
+ or not is_one_sequence_between(
+ closing.opening_bracket,
+ closing,
+ self.leaves,
+ brackets=(token.LSQB, token.RSQB),
)
- return comma.parent.type == syms.listmaker
+ )
if self.is_import:
return True
return bool(self.leaves or self.comments)
+@dataclass
+class RHSResult:
+ """Intermediate split result from a right hand split."""
+
+ head: Line
+ body: Line
+ tail: Line
+ opening_bracket: Leaf
+ closing_bracket: Leaf
+
+
@dataclass
class LinesBlock:
"""Class that holds information about a block of formatted lines.
mode: Mode
previous_line: Optional[Line] = None
previous_block: Optional[LinesBlock] = None
- previous_defs: List[int] = field(default_factory=list)
+ previous_defs: List[Line] = field(default_factory=list)
semantic_leading_comment: Optional[LinesBlock] = None
def maybe_empty_lines(self, current_line: Line) -> LinesBlock:
if self.previous_line is None
else before - previous_after
)
+ if (
+ Preview.module_docstring_newlines in current_line.mode
+ and self.previous_block
+ and self.previous_block.previous_block is None
+ and len(self.previous_block.original_line.leaves) == 1
+ and self.previous_block.original_line.is_triple_quoted_string
+ ):
+ before = 1
+
block = LinesBlock(
mode=self.mode,
previous_block=self.previous_block,
and (self.semantic_leading_comment is None or before)
):
self.semantic_leading_comment = block
- elif not current_line.is_decorator:
+ # `or before` means this decorator already has an empty line before
+ elif not current_line.is_decorator or before:
self.semantic_leading_comment = None
self.previous_line = current_line
first_leaf.prefix = ""
else:
before = 0
+
+ user_had_newline = bool(before)
depth = current_line.depth
- while self.previous_defs and self.previous_defs[-1] >= depth:
+
+ previous_def = None
+ while self.previous_defs and self.previous_defs[-1].depth >= depth:
+ previous_def = self.previous_defs.pop()
+
+ if previous_def is not None:
+ assert self.previous_line is not None
if self.mode.is_pyi:
- assert self.previous_line is not None
if depth and not current_line.is_def and self.previous_line.is_def:
# Empty lines between attributes and methods should be preserved.
- before = min(1, before)
+ before = 1 if user_had_newline else 0
+ elif (
+ Preview.blank_line_after_nested_stub_class in self.mode
+ and previous_def.is_class
+ and not previous_def.is_stub_class
+ ):
+ before = 1
elif depth:
before = 0
else:
before = 1
elif (
not depth
- and self.previous_defs[-1]
+ and previous_def.depth
and current_line.leaves[-1].type == token.COLON
and (
current_line.leaves[0].value
before = 1
else:
before = 2
- self.previous_defs.pop()
+
if current_line.is_decorator or current_line.is_def or current_line.is_class:
- return self._maybe_empty_lines_for_class_or_def(current_line, before)
+ return self._maybe_empty_lines_for_class_or_def(
+ current_line, before, user_had_newline
+ )
if (
self.previous_line
and self.previous_line.is_import
and not current_line.is_import
+ and not current_line.is_fmt_pass_converted(first_leaf_matches=is_import)
and depth == self.previous_line.depth
):
return (before or 1), 0
and self.previous_line.is_class
and current_line.is_triple_quoted_string
):
+ if Preview.no_blank_line_before_class_docstring in current_line.mode:
+ return 0, 1
return before, 1
- if (
- Preview.remove_block_trailing_newline in current_line.mode
- and self.previous_line
- and self.previous_line.opens_block
- ):
+ if self.previous_line and self.previous_line.opens_block:
return 0, 0
return before, 0
- def _maybe_empty_lines_for_class_or_def(
- self, current_line: Line, before: int
+ def _maybe_empty_lines_for_class_or_def( # noqa: C901
+ self, current_line: Line, before: int, user_had_newline: bool
) -> Tuple[int, int]:
if not current_line.is_decorator:
- self.previous_defs.append(current_line.depth)
+ self.previous_defs.append(current_line)
if self.previous_line is None:
# Don't insert empty lines before the first line in the file.
return 0, 0
):
slc = self.semantic_leading_comment
if (
- Preview.empty_lines_before_class_or_def_with_leading_comments
- in current_line.mode
- and slc is not None
+ slc is not None
and slc.previous_block is not None
and not slc.previous_block.original_line.is_class
and not slc.previous_block.original_line.opens_block
newlines = 0
else:
newlines = 1
+ # Remove case `self.previous_line.depth > current_line.depth` below when
+ # this becomes stable.
+ #
+ # Don't inspect the previous line if it's part of the body of the previous
+ # statement in the same level, we always want a blank line if there's
+ # something with a body preceding.
+ elif (
+ Preview.blank_line_between_nested_and_def_stub_file in current_line.mode
+ and self.previous_line.depth > current_line.depth
+ ):
+ newlines = 1
elif (
current_line.is_def or current_line.is_decorator
) and not self.previous_line.is_def:
newlines = 0
else:
newlines = 1 if current_line.depth else 2
+ # If a user has left no space after a dummy implementation, don't insert
+ # new lines. This is useful for instance for @overload or Protocols.
+ if (
+ Preview.dummy_implementations in self.mode
+ and self.previous_line.is_stub_def
+ and not user_had_newline
+ ):
+ newlines = 0
if comment_to_add_newlines is not None:
previous_block = comment_to_add_newlines.previous_block
if previous_block is not None:
new_line.append(comment_leaf, preformatted=True)
-def is_line_short_enough(line: Line, *, line_length: int, line_str: str = "") -> bool:
- """Return True if `line` is no longer than `line_length`.
-
+def is_line_short_enough( # noqa: C901
+ line: Line, *, mode: Mode, line_str: str = ""
+) -> bool:
+ """For non-multiline strings, return True if `line` is no longer than `line_length`.
+ For multiline strings, looks at the context around `line` to determine
+ if it should be inlined or split up.
Uses the provided `line_str` rendering, if any, otherwise computes a new one.
"""
if not line_str:
line_str = line_to_string(line)
- return (
- len(line_str) <= line_length
- and "\n" not in line_str # multiline strings
- and not line.contains_standalone_comments()
- )
+
+ width = str_width if mode.preview else len
+
+ if Preview.multiline_string_handling not in mode:
+ return (
+ width(line_str) <= mode.line_length
+ and "\n" not in line_str # multiline strings
+ and not line.contains_standalone_comments()
+ )
+
+ if line.contains_standalone_comments():
+ return False
+ if "\n" not in line_str:
+ # No multiline strings (MLS) present
+ return width(line_str) <= mode.line_length
+
+ first, *_, last = line_str.split("\n")
+ if width(first) > mode.line_length or width(last) > mode.line_length:
+ return False
+
+ # Traverse the AST to examine the context of the multiline string (MLS),
+ # tracking aspects such as depth and comma existence,
+ # to determine whether to split the MLS or keep it together.
+ # Depth (which is based on the existing bracket_depth concept)
+ # is needed to determine nesting level of the MLS.
+ # Includes special case for trailing commas.
+ commas: List[int] = [] # tracks number of commas per depth level
+ multiline_string: Optional[Leaf] = None
+ # store the leaves that contain parts of the MLS
+ multiline_string_contexts: List[LN] = []
+
+ max_level_to_update: Union[int, float] = math.inf # track the depth of the MLS
+ for i, leaf in enumerate(line.leaves):
+ if max_level_to_update == math.inf:
+ had_comma: Optional[int] = None
+ if leaf.bracket_depth + 1 > len(commas):
+ commas.append(0)
+ elif leaf.bracket_depth + 1 < len(commas):
+ had_comma = commas.pop()
+ if (
+ had_comma is not None
+ and multiline_string is not None
+ and multiline_string.bracket_depth == leaf.bracket_depth + 1
+ ):
+ # Have left the level with the MLS, stop tracking commas
+ max_level_to_update = leaf.bracket_depth
+ if had_comma > 0:
+ # MLS was in parens with at least one comma - force split
+ return False
+
+ if leaf.bracket_depth <= max_level_to_update and leaf.type == token.COMMA:
+ # Ignore non-nested trailing comma
+ # directly after MLS/MLS-containing expression
+ ignore_ctxs: List[Optional[LN]] = [None]
+ ignore_ctxs += multiline_string_contexts
+ if not (leaf.prev_sibling in ignore_ctxs and i == len(line.leaves) - 1):
+ commas[leaf.bracket_depth] += 1
+ if max_level_to_update != math.inf:
+ max_level_to_update = min(max_level_to_update, leaf.bracket_depth)
+
+ if is_multiline_string(leaf):
+ if len(multiline_string_contexts) > 0:
+ # >1 multiline string cannot fit on a single line - force split
+ return False
+ multiline_string = leaf
+ ctx: LN = leaf
+ # fetch the leaf components of the MLS in the AST
+ while str(ctx) in line_str:
+ multiline_string_contexts.append(ctx)
+ if ctx.parent is None:
+ break
+ ctx = ctx.parent
+
+ # May not have a triple-quoted multiline string at all,
+ # in case of a regular string with embedded newlines and line continuations
+ if len(multiline_string_contexts) == 0:
+ return True
+
+ return all(val == 0 for val in commas)
def can_be_split(line: Line) -> bool:
def can_omit_invisible_parens(
- line: Line,
+ rhs: RHSResult,
line_length: int,
) -> bool:
- """Does `line` have a shape safe to reformat without optional parens around it?
+ """Does `rhs.body` 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.
"""
+ line = rhs.body
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:
+ delimiter_count = bt.delimiter_count_with_priority(max_priority)
+ if delimiter_count > 1:
# With more than one delimiter of a kind the optional parentheses read better.
return False
+ if delimiter_count == 1:
+ if (
+ Preview.wrap_multiple_context_managers_in_parens in line.mode
+ and max_priority == COMMA_PRIORITY
+ and rhs.head.is_with_or_async_with_stmt
+ ):
+ # For two context manager with statements, the optional parentheses read
+ # better. In this case, `rhs.body` is the context managers part of
+ # the with statement. `rhs.head` is the `with (` part on the previous
+ # line.
+ return False
+ # Otherwise it may also read better, but we don't do it today and requires
+ # careful considerations for all possible cases. See
+ # https://github.com/psf/black/issues/2156.
+
if max_priority == DOT_PRIORITY:
# A single stranded method call doesn't require optional parentheses.
return True