ASYNC_KEYWORDS = 7
ASSIGNMENT_EXPRESSIONS = 8
POS_ONLY_ARGUMENTS = 9
+ FORCE_OPTIONAL_PARENTHESES = 50
VERSION_TO_FEATURES: Dict[TargetVersion, Set[Feature]] = {
previous: Optional[Leaf] = None
_for_loop_depths: List[int] = field(default_factory=list)
_lambda_argument_depths: List[int] = field(default_factory=list)
+ invisible: List[Leaf] = field(default_factory=list)
def mark(self, leaf: Leaf) -> None:
"""Mark `leaf` with bracket-related metadata. Keep track of delimiters.
self.depth -= 1
opening_bracket = self.bracket_match.pop((self.depth, leaf.type))
leaf.opening_bracket = opening_bracket
+ if not leaf.value:
+ self.invisible.append(leaf)
leaf.bracket_depth = self.depth
if self.depth == 0:
delim = is_split_before_delimiter(leaf, self.previous)
if leaf.type in OPENING_BRACKETS:
self.bracket_match[self.depth, BRACKET[leaf.type]] = leaf
self.depth += 1
+ if not leaf.value:
+ self.invisible.append(leaf)
self.previous = leaf
self.maybe_increment_lambda_arguments(leaf)
self.maybe_increment_for_loop_variable(leaf)
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.
- # line_length=1 here was historically a bug that somehow became a feature.
- # See #762 and #781 for the full story.
- yield from right_hand_split(line, line_length=1, features=features)
+ # reported as not fitting a single line, as well as lines that contain
+ # pre-existing 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:
# 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.
- result: List[Line] = []
try:
- 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)
- )
+ result = run_transformer(line, transform, mode, features, line_str=line_str)
except CannotTransform:
continue
else:
line_length: int
normalize_strings: bool
+ __name__ = "StringTransformer"
@abstractmethod
def do_match(self, line: Line) -> TMatchResult:
)
new_line = line.clone()
- new_line.comments = line.comments
+ new_line.comments = line.comments.copy()
append_leaves(new_line, line, LL)
new_string_leaf = new_line.leaves[string_idx]
new_line = line.clone()
new_line.comments = line.comments.copy()
-
append_leaves(new_line, line, LL[: string_idx - 1])
string_leaf = Leaf(token.STRING, LL[string_idx].value)
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
- opening_bracket.type == token.LPAR
+ and opening_bracket.type == token.LPAR
and not opening_bracket.value
# the closing bracket is an optional paren
and closing_bracket.type == token.RPAR
# 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)
+ and can_omit_invisible_parens(body, line_length, omit_on_explode=omit)
):
omit = {id(closing_bracket), *omit}
try:
def is_one_tuple_between(opening: Leaf, closing: Leaf, leaves: List[Leaf]) -> bool:
"""Return True if content between `opening` and `closing` looks like a one-tuple."""
+ if opening.type != token.LPAR and closing.type != token.RPAR:
+ return False
+
depth = closing.bracket_depth + 1
for _opening_index, leaf in enumerate(leaves):
if leaf is opening:
a preceding closing bracket fits in one line.
Yielded sets are cumulative (contain results of previous yields, too). First
- set is empty.
+ 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()
- yield omit
+ if not line.should_explode:
+ yield omit
length = 4 * line.depth
opening_bracket: Optional[Leaf] = None
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 (
+ line.should_explode
+ and prev
+ and prev.type == token.COMMA
+ and not prev.was_checked
+ and not is_one_tuple_between(
+ leaf.opening_bracket, leaf, line.leaves
+ )
+ ):
+ # Never omit bracket pairs with pre-existing trailing commas.
+ # We need to explode on those.
+ break
+
inner_brackets.add(id(leaf))
elif leaf.type in CLOSING_BRACKETS:
- if index > 0 and line.leaves[index - 1].type in OPENING_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.clear()
yield omit
+ if (
+ line.should_explode
+ and prev
+ and prev.type == token.COMMA
+ and not prev.was_checked
+ and not is_one_tuple_between(leaf.opening_bracket, leaf, line.leaves)
+ ):
+ # Never omit bracket pairs with pre-existing trailing commas.
+ # We need to explode on those.
+ break
+
if leaf.value:
opening_bracket = leaf.opening_bracket
closing_bracket = leaf
return True
-def can_omit_invisible_parens(line: Line, line_length: int) -> bool:
+def can_omit_invisible_parens(
+ line: Line,
+ line_length: int,
+ omit_on_explode: Collection[LeafID] = (),
+) -> 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
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.
+ first = line.leaves[0]
+ second = line.leaves[1]
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
+ if _can_omit_opening_paren(line, first=first, line_length=line_length):
+ 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.
+ penultimate = line.leaves[-2]
+ last = line.leaves[-1]
+ if line.should_explode:
+ try:
+ penultimate, last = last_two_except(line.leaves, omit=omit_on_explode)
+ except LookupError:
+ # Turns out we'd omit everything. We cannot skip the optional parentheses.
+ return False
+
if (
last.type == token.RPAR
or last.type == token.RBRACE
# unnecessary.
return True
- length = 4 * line.depth
- seen_other_brackets = False
- for _index, leaf, leaf_length in enumerate_with_length(line):
+ if (
+ line.should_explode
+ and penultimate.type == token.COMMA
+ and not penultimate.was_checked
+ ):
+ # The rightmost non-omitted bracket pair is the one we want to explode on.
+ return True
+
+ if _can_omit_closing_paren(line, last=last, line_length=line_length):
+ return True
+
+ return False
+
+
+def _can_omit_opening_paren(line: Line, *, first: Leaf, line_length: int) -> bool:
+ """See `can_omit_invisible_parens`."""
+ remainder = False
+ length = 4 * line.depth
+ _index = -1
+ 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 leaf is last.opening_bracket:
- if seen_other_brackets or length <= line_length:
- return True
+ if length > line_length:
+ break
- elif leaf.type in OPENING_BRACKETS:
+ if leaf.type in OPENING_BRACKETS:
# There are brackets we can further split on.
- seen_other_brackets = True
+ remainder = False
+
+ else:
+ # checked the entire string and line length wasn't exceeded
+ if len(line.leaves) == _index + 1:
+ return True
+
+ return False
+
+
+def _can_omit_closing_paren(line: Line, *, last: Leaf, line_length: int) -> bool:
+ """See `can_omit_invisible_parens`."""
+ 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
+def last_two_except(leaves: List[Leaf], omit: Collection[LeafID]) -> Tuple[Leaf, Leaf]:
+ """Return (penultimate, last) leaves skipping brackets in `omit` and contents."""
+ stop_after = None
+ last = None
+ for leaf in reversed(leaves):
+ if stop_after:
+ if leaf is stop_after:
+ stop_after = None
+ continue
+
+ if last:
+ return leaf, last
+
+ if id(leaf) in omit:
+ stop_after = leaf.opening_bracket
+ else:
+ last = leaf
+ else:
+ raise LookupError("Last two leaves were also skipped")
+
+
+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 not (
+ transform.__name__ == "rhs"
+ and line.bracket_tracker.invisible
+ and not any(bracket.value for bracket in line.bracket_tracker.invisible)
+ and not line.contains_multiline_strings()
+ and not result[0].contains_uncollapsable_type_comments()
+ and not result[0].contains_unsplittable_type_ignore()
+ and not is_line_short_enough(result[0], line_length=mode.line_length)
+ ):
+ 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
+
+
def get_cache_file(mode: Mode) -> Path:
return CACHE_DIR / f"cache.{mode.get_cache_key()}.pickle"