[GR-14920]: StringIO#close should be idempotent.

eregon · eregon · commit c155ca1b736d · 2019-04-03T02:55:32.000-07:00
PullRequest: truffleruby/768
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -9,6 +9,7 @@ Bug fixes:
 * `rb_protect` now returns `Qnil` when an error occurs.
 * Fixed a race condition when using the interpolate-once (`/o`) modifier in
   regular expressions.
+* Calling `StringIO#close` multiple times no longer raises an exception (#1640).
 
 New features:
 
diff --git a/lib/truffle/stringio.rb b/lib/truffle/stringio.rb
@@ -234,7 +234,6 @@ def write(str)
   alias_method :write_nonblock, :write
 
   def close
-    raise IOError, 'closed stream' if closed?
     @readable = @writable = nil
   end
 
diff --git a/spec/tags/library/stringio/close_tags.txt b/spec/tags/library/stringio/close_tags.txt
