Attempting to modify instances of NSString or NSArray causes crash

[jesper@…]

Creating an instance of NSString or NSArray, and then attempting to modify it, causes a crash in MacRuby 0.4 (built from source, revision 1541):

$ macirb 
irb(main):001:0> str = NSString.stringWithString 'a'
=> "a"
irb(main):002:0> str << 'b'
(irb):2: [BUG] Bus Error
MacRuby version 0.4 (ruby 1.9.1) [universal-darwin9.5, x86_64]

$ macirb 
irb(main):001:0> arr = NSArray.arrayWithObject 'a'
=> ["a"]
irb(main):002:0> arr << 'b'
/Library/Frameworks/MacRuby.framework/Versions/0.4/usr/lib/ruby/1.9.1/irb.rb:302: [BUG] Segmentation fault
MacRuby version 0.4 (ruby 1.9.1) [universal-darwin9.5, x86_64]

(Yes, I know that NSString and NSArray are immutable types, but a bus error or segfault seems a bit harsh.)

[jesper@…]

Cc Me!

[lsansonetti@…]

Thanks for the report, this is likely a bug in the YARV #<< optimization. We do check for mutability before doing any destructive operations.

$ macruby -e 's=NSString.string; s.strip!'
-e:1:in `strip!': can't modify immutable string (RuntimeError)
	from -e:1:in `<main>'

Also, I noticed that the check doesn't work for NSArray in 64-bit.

$ arch -i386 macruby -e "a = NSArray.array; a.clear"
-e:1:in `clear': can't modify frozen/immutable array (RuntimeError)
	from -e:1:in `<main>'
$ arch -x86_64 macruby -e "a = NSArray.array; a.clear"

[lsansonetti@…]

Definitely fixed in trunk.

$ ./miniruby -e "str = NSString.stringWithString 'a'; str << 'b'"
can't modify frozen/immutable string (RuntimeError)