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_name_token, is_lpar_token, is_rpar_token
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
"""A readable split that fits the allotted line length is impossible."""
-@dataclass
+# This isn't a dataclass because @dataclass + Generic breaks mypyc.
+# See also https://github.com/mypyc/mypyc/issues/827.
class LineGenerator(Visitor[Line]):
"""Generates reformatted Line objects. Empty lines are not emitted.
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 __init__(self, mode: Mode, remove_u_prefix: bool = False) -> None:
+ self.mode = mode
+ self.remove_u_prefix = remove_u_prefix
+ self.current_line: Line
+ self.__post_init__()
def line(self, indent: int = 0) -> Iterator[Line]:
"""Generate a line.
"""Visit a statement.
This implementation is shared for `if`, `while`, `for`, `try`, `except`,
- `def`, `with`, `class`, `assert` and assignments.
+ `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.
"""
normalize_invisible_parens(node, parens_after=parens)
for child in node.children:
- if child.type == token.NAME and child.value in keywords: # type: ignore
+ if is_name_token(child) and child.value in keywords:
yield from self.line()
yield from self.visit(child)
+ def visit_match_case(self, node: Node) -> Iterator[Line]:
+ """Visit either a match or case statement."""
+ normalize_invisible_parens(node, parens_after=set())
+
+ yield from self.line()
+ for child in node.children:
+ 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):
self.visit_async_funcdef = self.visit_async_stmt
self.visit_decorated = self.visit_decorators
+ # PEP 634
+ self.visit_match_stmt = self.visit_match_case
+ self.visit_case_block = self.visit_match_case
+
def transform_line(
line: Line, mode: Mode, features: Collection[Feature] = ()
transformers = [left_hand_split]
else:
- def rhs(line: Line, features: Collection[Feature]) -> Iterator[Line]:
+ def _rhs(
+ self: object, line: Line, features: Collection[Feature]
+ ) -> Iterator[Line]:
"""Wraps calls to `right_hand_split`.
The calls increasingly `omit` right-hand trailers (bracket pairs with
line, line_length=mode.line_length, features=features
)
+ # HACK: nested functions (like _rhs) compiled by mypyc don't retain their
+ # __name__ attribute which is needed in `run_transformer` further down.
+ # Unfortunately a nested class breaks mypyc too. So a class must be created
+ # via type ... https://github.com/mypyc/mypyc/issues/884
+ rhs = type("rhs", (), {"__call__": _rhs})()
+
if mode.experimental_string_processing:
if line.inside_brackets:
transformers = [
yield from right_hand_split(line, line_length, features=features, omit=omit)
return
- except CannotSplit:
+ 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(
" 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)
try:
last_leaf = line.leaves[-1]
except IndexError:
- raise CannotSplit("Line empty")
+ 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")
+ raise CannotSplit("No delimiters found") from None
if delimiter_priority == DOT_PRIORITY:
if bt.delimiter_count_with_priority(delimiter_priority) == 1:
elif node.type == syms.import_from:
# "import from" nodes store parentheses directly as part of
# the statement
- if child.type == token.LPAR:
+ if is_lpar_token(child):
# make parentheses invisible
- child.value = "" # type: ignore
+ child.value = ""
node.children[-1].value = "" # type: ignore
elif child.type != token.STAR:
# insert invisible parentheses
first = node.children[0]
last = node.children[-1]
- if first.type == token.LPAR and last.type == token.RPAR:
+ if is_lpar_token(first) and is_rpar_token(last):
middle = node.children[1]
# make parentheses invisible
- first.value = "" # type: ignore
- last.value = "" # type: ignore
+ first.value = ""
+ last.value = ""
maybe_make_parens_invisible_in_atom(middle, parent=parent)
if is_atom_with_invisible_parens(middle):
result.extend(transform_line(transformed_line, mode=mode, features=features))
if (
- transform.__name__ != "rhs"
+ transform.__class__.__name__ != "rhs"
or not line.bracket_tracker.invisible
or any(bracket.value for bracket in line.bracket_tracker.invisible)
or line.contains_multiline_strings()