[Fix rubocop#13557] Mark Lint/NumericOperationWithConstantResult as…

… unsafe
Earlopain · Dec 12, 2024 · c186264 · c186264
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diff --git a/changelog/change_mark_numeric_result_constant_unsafe.md b/changelog/change_mark_numeric_result_constant_unsafe.md
@@ -0,0 +1 @@
+* [#13557](https://github.com/rubocop/rubocop/issues/13557): Mark `Lint/NumericOperationWithConstantResult` as unsafe. ([@earlopain][])
diff --git a/config/default.yml b/config/default.yml
@@ -2155,7 +2155,9 @@ Lint/NumberedParameterAssignment:
 Lint/NumericOperationWithConstantResult:
   Description: 'Checks for numeric operations with constant results.'
   Enabled: pending
+  Safe: false
   VersionAdded: '1.69'
+  VersionChanged: <<next>>
 
 Lint/OrAssignmentToConstant:
   Description: 'Checks unintended or-assignment to constant.'

diff --git a/lib/rubocop/cop/lint/numeric_operation_with_constant_result.rb b/lib/rubocop/cop/lint/numeric_operation_with_constant_result.rb
@@ -12,6 +12,12 @@ module Lint
       # Other numeric operations that are similarly leftover from debugging or mistakes
       # are handled by Lint/UselessNumericOperation.
       #
+      # @safety
+      #   This cop is unsafe in cases like `x -= x` where `x` is an Array. `x` would be
+      #   `[]` after the operation (not `0`) but the cop can't distinquish such cases.
+      #   Additionally, for `x % 1` when `x` is a String, it is a format call and doesn't
+      #   result in a numerical result.
+      #
       # @example
       #
       #   # bad
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		* [#13557](https://github.com/rubocop/rubocop/issues/13557): Mark `Lint/NumericOperationWithConstantResult` as unsafe. ([@earlopain][])