Caching does not deal with lists of lists correctly

[zickgraf]

The inner lists might get garbage collected. Hence, despite crisp caching, MorphismBetweenDirectSums is computed twice in the following example:

LoadPackage( "CAP" );

cat := CreateCapCategory( );

SetCachingOfCategoryCrisp( cat );

myobj := SymmetricGroup( 3 );
AddObject( cat, myobj );
mymor := GroupHomomorphismByImages( myobj, myobj );
AddMorphism( cat, mymor );

AddDirectSum( cat, function( l )
    
    Display( "DirectSum" );
    
    return myobj;
    
end );

AddMorphismBetweenDirectSums( cat, function( s, l, r )
    
    Display( "MorphismBetweenDirectSums" );
    
    return mymor;
    
end );

Finalize( cat );

result := MorphismBetweenDirectSums( [ [ mymor ] ] );
GASMAN("collect");
MorphismBetweenDirectSums( [ [ mymor ] ] );

[mohamed-barakat]

Impressive 😄