[MacRuby-devel] 0.2 available for testing

[Stephen Bannasch]

At 2:58 PM -0700 6/5/08, Laurent Sansonetti wrote:
>On Jun 5, 2008, at 2:41 PM, Stephen Bannasch wrote:
>
>> At 4:28 PM -0400 6/5/08, Richard Kilmer wrote:
>>> On Jun 5, 2008, at 4:22 PM, Stephen Bannasch wrote:
>>>> After clicking the Spin button the circle spins for a little over 1s
>>>> before the program crashes.
>>>
>>> Do you have the iPhone sdk installed by chance?
>>
>> No.
>>
>>> Just FYI, I svn up'd, built and CircleView runs just great.
>>
>> Hmmm ... is there a way to run it with gdb and watch the variable 
>> @layoutManager and break and display a stack frame when it is set to 
>> nil?
>
>It's not as easy.
>
>In rb_main.rb, add the following line at the very beginning of the file:
>
>   GC.disable
>
>Then, try to reproduce the bug. If it doesn't reproduce, then it's a
>GC bug.

I added GC.disable and clicking Spin worked. So it's a GC bug -- what do I need to look for to fix it?

Before I disabled the GC I did this investigation:


I setup a counter to find out how many times the glyphRange.location.upto do loop is called.

  def initWithFrame(frame)
    super(frame)

    @glyphRange_location_call_count = 0

And then I added these debugging statements inside the glyphRange.location.upto do loop

    glyphRange.location.upto(glyphRange.location + glyphRange.length - 1) do |i|
      $stderr.puts "@layoutManager == nil: #{@layoutManger == nil}, times called: #{@glyphRange_location_call_count}"
      @glyphRange_location_call_count += 1

This is what happens when I start the app:

[Session started at 2008-06-05 20:01:10 -0400.]
@layoutManager == nil: true, times called: 0
...
@layoutManager == nil: true, times called: 141

Then I click the Spin button:

#<NSCFTimer:0x16497e0>
@layoutManager == nil: true, times called: 142
@layoutManager == nil: true, times called: 143
...
@layoutManager == nil: true, called: 2432
@layoutManager == nil: true, called: 2433
/Users/stephen/Desktop/CircleView/build/Release/CircleView.app/Contents/Resources/CircleView.rb:66:in `block in drawRect': undefined method `+' for nil:NilClass (NoMethodError)
	from /Users/stephen/Desktop/CircleView/build/Release/CircleView.app/Contents/Resources/CircleView.rb:53:in `upto'
	from /Users/stephen/Desktop/CircleView/build/Release/CircleView.app/Contents/Resources/CircleView.rb:53:in `drawRect'
	from /Users/stephen/Desktop/CircleView/build/Release/CircleView.app/Contents/Resources/rb_main.rb:22:in `NSApplicationMain'
	from /Users/stephen/Desktop/CircleView/build/Release/CircleView.app/Contents/Resources/rb_main.rb:22:in `<main>'

Ths is repeatable however the number of iterations before the crash varies.

I don't understand why @layoutManger appears to be nil the whole time.