[TYPO3-core] RFC #9803: getTreeList causes duplicate entry sql error in cache_treelist

[Christian Kuhn]

Hey Rupert,

Rupert Germann wrote:
> took me a while to get empty cache entries in the table.
> The main point is that this happens only if getTreelist is called with a
> positive ID (which does not happen in the core)
> 
> your patch works, but I think you fix the problem at the wrong end. If
> empty results are not returned they should of course not be cached at all.
> 
> see attached patch where I moved the check for the empty result to the
> insert query.

The method returns an empty string if no subpages are found (and if $id
is a positive int). So, why not cache the empty result, this will save
some executed code and queries (at minimum a sys_page->getRawRecord
query and the $res query. More for special situations like mountpoints).
What do you think?

Thanks
Christian