import sys
from typing import Collection, Iterator, List, Optional, Set, Union
-from dataclasses import dataclass, field
-
-from black.nodes import WHITESPACE, STATEMENT, STANDALONE_COMMENT
+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
from black.numerics import normalize_numeric_literal
from black.strings import get_string_prefix, fix_docstring
from black.strings import normalize_string_prefix, normalize_string_quotes
-from black.trans import Transformer, CannotTransform, StringMerger
-from black.trans import StringSplitter, StringParenWrapper, StringParenStripper
-from black.mode import Mode
-from black.mode import Feature
+from black.trans import Transformer, CannotTransform, StringMerger, StringSplitter
+from black.trans import StringParenWrapper, StringParenStripper, hug_power_op
+from black.mode import Mode, Feature, Preview
from blib2to3.pytree import Node, Leaf
from blib2to3.pgen2 import token
"""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) -> None:
+ self.mode = mode
+ self.current_line: Line
+ self.__post_init__()
def line(self, indent: int = 0) -> Iterator[Line]:
"""Generate a line.
normalize_prefix(node, inside_brackets=any_open_brackets)
if self.mode.string_normalization and node.type == token.STRING:
- node.value = normalize_string_prefix(
- node.value, remove_u_prefix=self.remove_u_prefix
- )
+ node.value = normalize_string_prefix(node.value)
node.value = normalize_string_quotes(node.value)
if node.type == token.NUMBER:
normalize_numeric_literal(node)
"""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):
if is_docstring(leaf) and "\\\n" not in leaf.value:
# We're ignoring docstrings with backslash newline escapes because changing
# indentation of those changes the AST representation of the code.
- prefix = get_string_prefix(leaf.value)
- docstring = leaf.value[len(prefix) :] # Remove the prefix
+ docstring = normalize_string_prefix(leaf.value)
+ prefix = get_string_prefix(docstring)
+ docstring = docstring[len(prefix) :] # Remove the prefix
quote_char = docstring[0]
# A natural way to remove the outer quotes is to do:
# docstring = docstring.strip(quote_char)
# characters but only if they are the same as the first.
quote_len = 1 if docstring[1] != quote_char else 3
docstring = docstring[quote_len:-quote_len]
+ docstring_started_empty = not docstring
if is_multiline_string(leaf):
indent = " " * 4 * self.current_line.depth
# Odd number of tailing backslashes, add some padding to
# avoid escaping the closing string quote.
docstring += " "
- else:
- # Add some padding if the docstring is empty.
+ elif not docstring_started_empty:
docstring = " "
# We could enforce triple quotes at this point.
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] = ()
and not (line.inside_brackets and line.contains_standalone_comments())
):
# Only apply basic string preprocessing, since lines shouldn't be split here.
- if mode.experimental_string_processing:
+ if Preview.string_processing in mode:
transformers = [string_merge, string_paren_strip]
else:
transformers = []
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
)
- if mode.experimental_string_processing:
+ # 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 Preview.string_processing in mode:
if line.inside_brackets:
transformers = [
string_merge,
transformers = [delimiter_split, standalone_comment_split, rhs]
else:
transformers = [rhs]
+ # It's always safe to attempt hugging of power operations and pretty much every line
+ # could match.
+ transformers.append(hug_power_op)
for transform in transformers:
# We are accumulating lines in `result` because we might want to abort
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)
original.is_def
and opening_bracket.value == "("
and not any(leaf.type == token.COMMA for leaf in leaves)
+ # In particular, don't add one within a parenthesized return annotation.
+ # Unfortunately the indicator we're in a return annotation (RARROW) may
+ # be defined directly in the parent node, the parent of the parent ...
+ # and so on depending on how complex the return annotation is.
+ # This isn't perfect and there's some false negatives but they are in
+ # contexts were a comma is actually fine.
+ and not any(
+ node.prev_sibling.type == RARROW
+ for node in (
+ leaves[0].parent,
+ getattr(leaves[0].parent, "parent", None),
+ )
+ if isinstance(node, Node) and isinstance(node.prev_sibling, Leaf)
+ )
)
if original.is_import or no_commas:
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):
+ assert is_rpar_token(node.children[-1])
# make parentheses invisible
- child.value = "" # type: ignore
- node.children[-1].value = "" # type: ignore
+ child.value = ""
+ node.children[-1].value = ""
elif child.type != token.STAR:
# insert invisible parentheses
node.insert_child(index, Leaf(token.LPAR, ""))
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):
if (
prev
and prev.type == token.COMMA
+ and leaf.opening_bracket is not None
and not is_one_tuple_between(
leaf.opening_bracket, leaf, line.leaves
)
if (
prev
and prev.type == token.COMMA
+ and leaf.opening_bracket is not None
and not is_one_tuple_between(leaf.opening_bracket, leaf, line.leaves)
):
# Never omit bracket pairs with trailing commas.
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)
+ if (
+ 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()
+ or result[0].contains_uncollapsable_type_comments()
+ or result[0].contains_unsplittable_type_ignore()
+ or is_line_short_enough(result[0], line_length=mode.line_length)
+ # If any leaves have no parents (which _can_ occur since
+ # `transform(line)` potentially destroys the line's underlying node
+ # structure), then we can't proceed. Doing so would cause the below
+ # call to `append_leaves()` to fail.
+ or any(leaf.parent is None for leaf in line.leaves)
):
return result