Type,
TypeVar,
Union,
+ cast,
)
from appdirs import user_cache_dir
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:
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.
and not line.is_import
):
omit = {id(closing_bracket), *omit}
- delimiter_count = body.bracket_tracker.delimiter_count_with_priority()
- first = body.leaves[0]
- last = body.leaves[-1]
- if (
- delimiter_count == 0
- or delimiter_count == 1
- and (
- first.type in OPENING_BRACKETS
- or 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 can_omit_invisible_parens(body, line_length):
try:
- yield from right_hand_split(line, py36=py36, omit=omit)
+ yield from right_hand_split(line, line_length, py36=py36, omit=omit)
return
except CannotSplit:
pass
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:
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`.
)
+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__))