from preamble:

"Change Set:		CollectionAtRandom
Date:			6 November 2003
Author:			Lukas Renggli

md: Just the latest version with a correct chanset preamble... ;-)

-additional changes (and [et] [er]) from stepane.

The message #atRandom is not thread-save when being used concurrently on
different collections or integers. As a test try to evaluate the
following expressions in your image, the random generator provided by
Collection gets corrupted:

        [ [ (1 to: 100) atRandom ] repeat ] forkAt: 30.
        [ [ 100 atRandom ] repeat ] forkAt: 30.
        
This is a critical bug!! As an example the superb web-framework Seaside
uses random key-generation to identify its sessions. If other threads in
your image use #atRandom problems might arise.

The attached change-set solves the problem by introducing a critical
section to the Collection class providing the random generator."!
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