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More concise formatting for dummy implementations (#3796)
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hauntsaninja authored Aug 4, 2023
1 parent 59e8936 commit c160e4b
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Showing 7 changed files with 135 additions and 11 deletions.
2 changes: 2 additions & 0 deletions CHANGES.md
Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,8 @@

<!-- Changes that affect Black's preview style -->

- More concise formatting for dummy implementations (#3796)

### Configuration

<!-- Changes to how Black can be configured -->
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10 changes: 7 additions & 3 deletions src/black/linegen.py
Original file line number Diff line number Diff line change
Expand Up @@ -281,7 +281,9 @@ def visit_match_case(self, node: Node) -> Iterator[Line]:

def visit_suite(self, node: Node) -> Iterator[Line]:
"""Visit a suite."""
if self.mode.is_pyi and is_stub_suite(node):
if (
self.mode.is_pyi or Preview.dummy_implementations in self.mode
) and is_stub_suite(node):
yield from self.visit(node.children[2])
else:
yield from self.visit_default(node)
Expand All @@ -296,7 +298,9 @@ def visit_simple_stmt(self, node: Node) -> Iterator[Line]:

is_suite_like = node.parent and node.parent.type in STATEMENT
if is_suite_like:
if self.mode.is_pyi and is_stub_body(node):
if (
self.mode.is_pyi or Preview.dummy_implementations in self.mode
) and is_stub_body(node):
yield from self.visit_default(node)
else:
yield from self.line(+1)
Expand All @@ -305,7 +309,7 @@ def visit_simple_stmt(self, node: Node) -> Iterator[Line]:

else:
if (
not self.mode.is_pyi
not (self.mode.is_pyi or Preview.dummy_implementations in self.mode)
or not node.parent
or not is_stub_suite(node.parent)
):
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27 changes: 23 additions & 4 deletions src/black/lines.py
Original file line number Diff line number Diff line change
Expand Up @@ -165,6 +165,13 @@ def is_def(self) -> bool:
and second_leaf.value == "def"
)

@property
def is_stub_def(self) -> bool:
"""Is this line a function definition with a body consisting only of "..."?"""
return self.is_def and self.leaves[-4:] == [Leaf(token.COLON, ":")] + [
Leaf(token.DOT, ".") for _ in range(3)
]

@property
def is_class_paren_empty(self) -> bool:
"""Is this a class with no base classes but using parentheses?
Expand Down Expand Up @@ -578,6 +585,8 @@ def _maybe_empty_lines(self, current_line: Line) -> Tuple[int, int]:
first_leaf.prefix = ""
else:
before = 0

user_had_newline = bool(before)
depth = current_line.depth

previous_def = None
Expand All @@ -589,7 +598,7 @@ def _maybe_empty_lines(self, current_line: Line) -> Tuple[int, int]:
if self.mode.is_pyi:
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)
before = 1 if user_had_newline else 0
elif (
Preview.blank_line_after_nested_stub_class in self.mode
and previous_def.is_class
Expand Down Expand Up @@ -624,7 +633,9 @@ def _maybe_empty_lines(self, current_line: Line) -> Tuple[int, int]:
before = 2

if current_line.is_decorator or current_line.is_def or current_line.is_class:
return self._maybe_empty_lines_for_class_or_def(current_line, before)
return self._maybe_empty_lines_for_class_or_def(
current_line, before, user_had_newline
)

if (
self.previous_line
Expand All @@ -648,8 +659,8 @@ def _maybe_empty_lines(self, current_line: Line) -> Tuple[int, int]:
return 0, 0
return before, 0

def _maybe_empty_lines_for_class_or_def(
self, current_line: Line, before: int
def _maybe_empty_lines_for_class_or_def( # noqa: C901
self, current_line: Line, before: int, user_had_newline: bool
) -> Tuple[int, int]:
if not current_line.is_decorator:
self.previous_defs.append(current_line)
Expand Down Expand Up @@ -715,6 +726,14 @@ def _maybe_empty_lines_for_class_or_def(
newlines = 0
else:
newlines = 1 if current_line.depth else 2
# If a user has left no space after a dummy implementation, don't insert
# new lines. This is useful for instance for @overload or Protocols.
if (
Preview.dummy_implementations in self.mode
and self.previous_line.is_stub_def
and not user_had_newline
):
newlines = 0
if comment_to_add_newlines is not None:
previous_block = comment_to_add_newlines.previous_block
if previous_block is not None:
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1 change: 1 addition & 0 deletions src/black/mode.py
Original file line number Diff line number Diff line change
Expand Up @@ -182,6 +182,7 @@ class Preview(Enum):
skip_magic_trailing_comma_in_subscript = auto()
wrap_long_dict_values_in_parens = auto()
wrap_multiple_context_managers_in_parens = auto()
dummy_implementations = auto()


class Deprecated(UserWarning):
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4 changes: 2 additions & 2 deletions tests/data/miscellaneous/force_py36.py
Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
# The input source must not contain any Py36-specific syntax (e.g. argument type
# annotations, trailing comma after *rest) or this test becomes invalid.
def long_function_name(argument_one, argument_two, argument_three, argument_four, argument_five, argument_six, *rest): ...
def long_function_name(argument_one, argument_two, argument_three, argument_four, argument_five, argument_six, *rest): pass
# output
# The input source must not contain any Py36-specific syntax (e.g. argument type
# annotations, trailing comma after *rest) or this test becomes invalid.
Expand All @@ -13,4 +13,4 @@ def long_function_name(
argument_six,
*rest,
):
...
pass
3 changes: 1 addition & 2 deletions tests/data/preview/comments7.py
Original file line number Diff line number Diff line change
Expand Up @@ -278,8 +278,7 @@ class C:
)
def test_fails_invalid_post_data(
self, pyramid_config, db_request, post_data, message
):
...
): ...


square = Square(4) # type: Optional[Square]
99 changes: 99 additions & 0 deletions tests/data/preview/dummy_implementations.py
Original file line number Diff line number Diff line change
@@ -0,0 +1,99 @@
from typing import NoReturn, Protocol, Union, overload


def dummy(a): ...
def other(b): ...


@overload
def a(arg: int) -> int: ...
@overload
def a(arg: str) -> str: ...
@overload
def a(arg: object) -> NoReturn: ...
def a(arg: Union[int, str, object]) -> Union[int, str]:
if not isinstance(arg, (int, str)):
raise TypeError
return arg

class Proto(Protocol):
def foo(self, a: int) -> int:
...

def bar(self, b: str) -> str: ...
def baz(self, c: bytes) -> str:
...


def dummy_two():
...
@dummy
def dummy_three():
...

def dummy_four():
...

@overload
def b(arg: int) -> int: ...

@overload
def b(arg: str) -> str: ...
@overload
def b(arg: object) -> NoReturn: ...

def b(arg: Union[int, str, object]) -> Union[int, str]:
if not isinstance(arg, (int, str)):
raise TypeError
return arg

# output

from typing import NoReturn, Protocol, Union, overload


def dummy(a): ...
def other(b): ...


@overload
def a(arg: int) -> int: ...
@overload
def a(arg: str) -> str: ...
@overload
def a(arg: object) -> NoReturn: ...
def a(arg: Union[int, str, object]) -> Union[int, str]:
if not isinstance(arg, (int, str)):
raise TypeError
return arg


class Proto(Protocol):
def foo(self, a: int) -> int: ...

def bar(self, b: str) -> str: ...
def baz(self, c: bytes) -> str: ...


def dummy_two(): ...
@dummy
def dummy_three(): ...


def dummy_four(): ...


@overload
def b(arg: int) -> int: ...


@overload
def b(arg: str) -> str: ...
@overload
def b(arg: object) -> NoReturn: ...


def b(arg: Union[int, str, object]) -> Union[int, str]:
if not isinstance(arg, (int, str)):
raise TypeError
return arg

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