[Fix #520] Disable Performance/BigDecimalWithNumericArgument by default

It keeps flip-flopping between versions.

Ref:
* #468
* #454

Author: Earlopain

changelog/change_disable_bigdecimal.md

@@ -0,0 +1 @@
+* [#520](https://github.com/rubocop/rubocop-performance/issues/520): Disable `Performance/BigDecimalWithNumericArgument` by default. ([@earlopain][])

config/default.yml

@@ -22,8 +22,9 @@ Performance/ArraySemiInfiniteRangeSlice:
 
 Performance/BigDecimalWithNumericArgument:
   Description: 'Convert numeric literal to string and pass it to `BigDecimal`.'
-  Enabled: 'pending'
+  Enabled: false
   VersionAdded: '1.7'
+  VersionChanged: <<next>>
 
 Performance/BindCall:
   Description: 'Use `bind_call(obj, args, ...)` instead of `bind(obj).call(args, ...)`.'

lib/rubocop/cop/performance/big_decimal_with_numeric_argument.rb

@@ -9,6 +9,11 @@ module Performance
       # Also identifies places where an integer string argument to BigDecimal should be converted to
       # an integer. Initializing from Integer is faster than from String for BigDecimal.
       #
+      # NOTE: This cop is disabled by default because the performance of initializing with a String
+      # and Number differ between versions. Additionally, performance depends on the size of the Number,
+      # and if it is an Integer or a Float. Since this is very specific to `bigdecimal` internals,
+      # suggestions from this cop are not unlikely to result in code that performs worse than before.
+      #
       # @example
       #   # bad
       #   BigDecimal(1.2, 3, exception: true)