[Pharo-project] Problem with PluggableListMorph

Jan. 16, 2012

      There are cases when PluggableListMorph has is inner list cache in nil:

*getListElementSelector: aSymbol
    "specify a selector that can be used to obtain a single element in the
underlying list"
    getListElementSelector := aSymbol.
    list := nil.  "this cache will not be updated if getListElementSelector
has been specified, so go ahead and remove it"*
...

But, there are some methods that send messages to that nil list and blow up
:D, such as:

*backgroundColorFor: aRow

    | anItem return |
    aRow ifNil: [ ^nil ].
    anItem := list at: aRow ifAbsent: [ ^ nil ].
...
*
Now, two solutions comes to my mind:

put one more ward in:

*backgroundColorFor: aRow

    | anItem return |
    (aRow isNil or: [ list isNil ]) ifTrue: [ ^nil ].
    anItem := list at: aRow ifAbsent: [ ^ nil ].
...
*
Or use #getList, which seems to be the most... cleaner.

*backgroundColorFor: aRow

    | anItem return |
    aRow ifNil: [ ^nil ].
    anItem := self getList at: aRow ifAbsent: [ ^ nil ].
...
*
?

Guille,
(meanwhile, opening a ticket :)).

Guillermo Polito

Guillermo Polito

tags

participants (1)