8.0.1 sorted changes lead to different sorting

[Michael Keppler]

Hi all, I experience different sorted collections after migration to 8.0.2, compared to 7.5.1. And I also found the reason in the "sorted" changes for Seaside.

If you need a testcase, just run this code on 8.0.2 and 7.5.1, the order will be different afterwards:

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(OrderedCollection with: '11' with: '12') asSortedCollection: [:a :b |
   (a size ~= b size) ifTrue: [
      a size > b size.
   ]
   ifFalse: [
      true.
   ].
].

The most interesting point is: If you try to debug that test case, it will return the 7.5.1 result. Only when it is executed as a single block, it returns a different result. Therefore I removed my theory of where the bug is located (which you might have seen in the first version of this post).

[Michael Keppler]

I found the reason. The SeaSide "sorted" migration should have replaced all "sorted:" by "isSorted:". This has not happened in

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Collection>>#asSortedCollection:

If the offending line is changed there, everything works fine again.

[wembley]

Michael -

I'm a bit confused. Here is Collection>>#asSortedColection: that is shipped in VA Smalltalk V8.0.2

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asSortedCollection: aBlock

   "Answer a new instance of SortedCollection whose elements are the
    elements of the receiver.  The sort order is defined by the two
    argument block, aBlock.  Each argument of the block represents
    an potential Object within the collection.  The block body contains
    code returning a Boolean which is true if the items need not be
    exchanged in terms of ordering and false if they are to be exchanged.

    Fail if aBlock is not a two-argument Block."

   ^(SortedCollection new: self size)
      sortBlock: aBlock;
      addAll: self;
      yourself

I don't see any reference to #sorted: in the method.

[Michael Keppler]

Sorry, you are completely right. We introduced a change in that method in 1998. And that change was wrongly included when we merged our existing 7.5.1 application with the new VAST 8.0.2.

Please accept my apologies.

[wembley]

Michael -

Don't worry about it -- I'm just glad the issue is resolved.

[Michael Keppler]

Ok, now it gets even more confusing: If I use clean 7.5.1 or 8.0.x images, the sorting is still wrong. After some debates with colleagues we found that our change _fixed_ the problem for us in all previous versions.

So, if you take my test code from the previous posting, _execute_ it, it will sort the elements in order "12", "11", although they should not change their order.

If you take my code and instead _debug_ it, the sorting will be correct (i.e. the bug not reproducable), because one of the printOn methods modifies the sortedCollection. If you implement SortedCollection>>#printOn: as empty method,then also the debugging will show the wrong sorting.