Formatter: Parenthesize long expressions in dicts #8437
Description
See #8436 for background.
Stable formatting of dicts with a long value results in a wrap that reduces readability
Unformatted:
if True:
___ = {
"x": "---",
"y": "--------------------------------------------------------------" if True else None,
"z": "---",
}Formatted (Ruff, Black stable):
if True:
___ = {
"x": "---",
"y": "--------------------------------------------------------------"
if True
else None,
"z": "---",
}Formatted (Black preview):
if True:
___ = {
"x": "---",
"y": (
"--------------------------------------------------------------"
if True
else None
),
"z": "---",
}With a shorter line, Ruff retains parenthesis when the lines are collapsed:
if True:
___ = {
"x": "---",
"y": ("----------------------------------------------------" if True else None),
"z": "---",
}However, these parenthesis should be removed as they are superfluous.
Black's preview style will remove these parenthesis:
if True:
___ = {
"x": "---",
"y": "----------------------------------------------------" if True else None,
"z": "---",
}See psf/black#620 psf/black#3440
Note that Black does not remove these parenthesis for calls or lists, see #8436 and #8438