Update String#sub to operate on dup of self

jruby · Jun 16, 2016 · eb33d89 · eb33d89
1 parent 07cecbb
commit eb33d89
Showing 2 changed files with 3 additions and 3 deletions.
diff --git a/spec/truffle/tags/core/string/sub_tags.txt b/spec/truffle/tags/core/string/sub_tags.txt
@@ -1,2 +1 @@
 fails(regexp):String#sub! with pattern and block raises a RuntimeError if the string is modified while substituting
-fails:String#sub with pattern, replacement returns a copy of self when no modification is made
diff --git a/truffle/src/main/ruby/core/string.rb b/truffle/src/main/ruby/core/string.rb
@@ -744,6 +744,7 @@ def upto(stop, exclusive=false)
   def sub(pattern, replacement=undefined)
     # Because of the behavior of $~, this is duplicated from sub! because
     # if we call sub! from sub, the last_match can't be updated properly.
+    dup = self.dup
 
     unless valid_encoding?
       raise ArgumentError, "invalid byte sequence in #{encoding}"
@@ -769,7 +770,7 @@ def sub(pattern, replacement=undefined)
     end
 
     pattern = Rubinius::Type.coerce_to_regexp(pattern, true) unless pattern.kind_of? Regexp
-    match = pattern.match_from(self, 0)
+    match = pattern.match_from(dup, 0)
 
     Regexp.last_match = match
 
@@ -799,7 +800,7 @@ def sub(pattern, replacement=undefined)
       ret.append(match.post_match)
       tainted ||= val.tainted?
     else
-      return self
+      return dup
     end
 
     ret.taint if tainted
Original file line number	Diff line number	Diff line change
		@@ -1,2 +1 @@
		fails(regexp):String#sub! with pattern and block raises a RuntimeError if the string is modified while substituting
		fails:String#sub with pattern, replacement returns a copy of self when no modification is made