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_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
should_split_rhs: bool = False
magic_trailing_comma: Optional[Leaf] = None
- def append(self, leaf: Leaf, preformatted: bool = False) -> None:
+ def append(
+ self, leaf: Leaf, preformatted: bool = False, track_bracket: bool = False
+ ) -> None:
"""Add a new `leaf` to the end of the line.
Unless `preformatted` is True, the `leaf` will receive a new consistent
leaf.prefix += whitespace(
leaf, complex_subscript=self.is_complex_subscript(leaf)
)
- if self.inside_brackets or not preformatted:
+ if self.inside_brackets or not preformatted or track_bracket:
self.bracket_tracker.mark(leaf)
if self.mode.magic_trailing_comma:
if self.has_magic_trailing_comma(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?"""
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:
- it's not a single-element subscript
Additionally, if ensure_removable:
- it's not from square bracket indexing
+ (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(
if not ensure_removable:
return True
+
comma = self.leaves[-1]
- return bool(comma.parent and comma.parent.type == syms.listmaker)
+ if comma.parent is None:
+ return False
+ 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),
+ )
+ )
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.
+
+ This is introduced so that the EmptyLineTracker can look behind the standalone
+ comments and adjust their empty lines for class or def lines.
+ """
+
+ mode: Mode
+ previous_block: Optional["LinesBlock"]
+ original_line: Line
+ before: int = 0
+ content_lines: List[str] = field(default_factory=list)
+ after: int = 0
+
+ def all_lines(self) -> List[str]:
+ empty_line = str(Line(mode=self.mode))
+ return (
+ [empty_line * self.before] + self.content_lines + [empty_line * self.after]
+ )
+
+
@dataclass
class EmptyLineTracker:
"""Provides a stateful method that returns the number of potential extra
are consumed by `maybe_empty_lines()` and included in the computation.
"""
- is_pyi: bool = False
+ mode: Mode
previous_line: Optional[Line] = None
- previous_after: int = 0
- previous_defs: List[int] = field(default_factory=list)
+ previous_block: Optional[LinesBlock] = None
+ previous_defs: List[Line] = field(default_factory=list)
+ semantic_leading_comment: Optional[LinesBlock] = None
- def maybe_empty_lines(self, current_line: Line) -> Tuple[int, int]:
+ def maybe_empty_lines(self, current_line: Line) -> LinesBlock:
"""Return the number of extra empty lines before and after the `current_line`.
This is for separating `def`, `async def` and `class` with extra empty
lines (two on module-level).
"""
before, after = self._maybe_empty_lines(current_line)
+ previous_after = self.previous_block.after if self.previous_block else 0
before = (
# Black should not insert empty lines at the beginning
# of the file
0
if self.previous_line is None
- else before - self.previous_after
+ else before - previous_after
+ )
+ block = LinesBlock(
+ mode=self.mode,
+ previous_block=self.previous_block,
+ original_line=current_line,
+ before=before,
+ after=after,
)
- self.previous_after = after
+
+ # Maintain the semantic_leading_comment state.
+ if current_line.is_comment:
+ if self.previous_line is None or (
+ not self.previous_line.is_decorator
+ # `or before` means this comment already has an empty line before
+ and (not self.previous_line.is_comment or before)
+ and (self.semantic_leading_comment is None or before)
+ ):
+ self.semantic_leading_comment = block
+ # `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
- return before, after
+ self.previous_block = block
+ return block
def _maybe_empty_lines(self, current_line: Line) -> Tuple[int, int]:
max_allowed = 1
if current_line.depth == 0:
- max_allowed = 1 if self.is_pyi else 2
+ max_allowed = 1 if self.mode.is_pyi else 2
if current_line.leaves:
# Consume the first leaf's extra newlines.
first_leaf = current_line.leaves[0]
else:
before = 0
depth = current_line.depth
- while self.previous_defs and self.previous_defs[-1] >= depth:
- if self.is_pyi:
+ while self.previous_defs and self.previous_defs[-1].depth >= depth:
+ 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)
+ elif (
+ Preview.blank_line_after_nested_stub_class in self.mode
+ and self.previous_defs[-1].is_class
+ and not self.previous_defs[-1].is_stub_class
+ ):
+ before = 1
elif depth:
before = 0
else:
before = 1
elif (
not depth
- and self.previous_defs[-1]
+ and self.previous_defs[-1].depth
and current_line.leaves[-1].type == token.COLON
and (
current_line.leaves[0].value
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
):
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
self, current_line: Line, before: int
) -> 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
if self.previous_line.is_decorator:
- if self.is_pyi and current_line.is_stub_class:
+ if self.mode.is_pyi and current_line.is_stub_class:
# Insert an empty line after a decorated stub class
return 0, 1
):
return 0, 0
+ comment_to_add_newlines: Optional[LinesBlock] = None
if (
self.previous_line.is_comment
and self.previous_line.depth == current_line.depth
and before == 0
):
- return 0, 0
+ slc = self.semantic_leading_comment
+ if (
+ 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
+ and slc.before <= 1
+ ):
+ comment_to_add_newlines = slc
+ else:
+ return 0, 0
- if self.is_pyi:
+ if self.mode.is_pyi:
if current_line.is_class or self.previous_line.is_class:
if self.previous_line.depth < current_line.depth:
newlines = 0
newlines = 0
else:
newlines = 1 if current_line.depth else 2
+ if comment_to_add_newlines is not None:
+ previous_block = comment_to_add_newlines.previous_block
+ if previous_block is not None:
+ comment_to_add_newlines.before = (
+ max(comment_to_add_newlines.before, newlines) - previous_block.after
+ )
+ newlines = 0
return newlines, 0
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 = 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