[GR-20257] Fix BigDecimal#to_s 5F formatting issue (#1711).

PullRequest: truffleruby/1205

Author: bjfish

CHANGELOG.md

@@ -43,6 +43,7 @@ Bug fixes:
 * Fixed BigDecimal coerce initial argument using `to_str` (#1826).
 * Make `Enumerable#chunk` work without a block (#1518).
 * Fixed issue with `SystemCallError.new` setting a backtrace.
+* Fixed `BigDecimal#to_s` formatting issue (#1711).
 
 Compatibility:
 

lib/truffle/bigdecimal.rb

@@ -242,12 +242,12 @@ def to_s(format = 'E')
 
         format '%s%s.%s',
                prefix,
-               add_spaces_to_s(before_dot, true, space_frequency),
-               add_spaces_to_s(after_dot, false, space_frequency)
+               add_spaces_to_s(before_dot, space_frequency),
+               add_spaces_to_s(after_dot, space_frequency)
       else
         format '%s0.%se%d',
                prefix,
-               add_spaces_to_s(unscaled_value, false, space_frequency),
+               add_spaces_to_s(unscaled_value, space_frequency),
                exponent_value
       end
     else
@@ -270,19 +270,14 @@ def self._load(data)
     BigDecimal(data.split(':').last)
   end
 
-  private def add_spaces_to_s(string, reverse, space_frequency)
+  private def add_spaces_to_s(string, space_frequency)
     return string if space_frequency == 0
 
     remainder = string.size % space_frequency
-    shift     = reverse ? remainder : 0
-    pieces    = (string.size / space_frequency).times.map { |i| string[space_frequency*i + shift, space_frequency] }
+    pieces    = (string.size / space_frequency).times.map { |i| string[space_frequency*i, space_frequency] }
 
     if remainder > 0
-      if reverse
-        pieces.unshift string[0...remainder]
-      else
-        pieces.push string[-remainder..-1]
-      end
+      pieces.push string[-remainder..-1]
     end
 
     pieces.join ' '

spec/ruby/library/bigdecimal/to_s_spec.rb

@@ -41,6 +41,7 @@
 
     str1 = '-123.45678 90123 45678 9'
     BigDecimal("-123.45678901234567890").to_s('5F').should ==  str1
+    BigDecimal('1000010').to_s('5F').should == "10000 10.0"
     # trailing zeroes removed
     BigDecimal("1.00000000000").to_s('1F').should == "1.0"
     # 0 is treated as no spaces