[Fix #11399] Add new Style/UnlessMinimizeNegations cop
#11662
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Fixes rubocop#11399. This PR adds new `Style/UnlessMinimizeNegations` cop. It minimizes the number of negations in an `unless` using De Morgan’s laws. ```ruby # bad (all terms negated) do_something unless !x && !y # good (all terms positive) do_something if x || y # bad (2 negations, 1 positive) do_something unless !x || !y || z # good (2 positives, 1 negation) do_something if x && y && !z ```
| module RuboCop | ||
| module Cop | ||
| module Style | ||
| # Minimizes the number of negations in an `unless` using De Morgan’s laws. |
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Why in unless only? Seems to me this should apply to all conditionals.
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More often people avoid unless than use it in difficult conditions.
# I don't think the corrected version is much better. Can be seen as a double negation.
do_something if x && !y && !z
do_something unless !x || y || z
# But such a case is not bad.
do_something if !x || !y || !z
do_something unless x && y && z
For if I would make a parameter (disabled by default). But, this case is related to other cops. Style/UnlessElse and Style/UnlessLogicalOperators with forbid_logical_operators.
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I see. I'd be fine to keeping this limited to unless but the rationale needs to be explained clearly in the cop and it's relation to existing cops.
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my 2c: I like the idea of conditionally supporting both if and unless. Perhaps the cop name could be just Style/MinimizeNegations with an option to target if/unless/both?
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I'll finalize it as soon as I have time.
Fixes #11399.
This PR adds new
Style/UnlessMinimizeNegationscop.It minimizes the number of negations in an
unlessusing De Morgan’s laws.Before submitting the PR make sure the following are checked:
[Fix #issue-number](if the related issue exists).master(if not - rebase it).bundle exec rake default. It executes all tests and runs RuboCop on its own code.{change_type}_{change_description}.mdif the new code introduces user-observable changes. See changelog entry format for details.