[TYPO3] Strange Warning: Invalid argument supplied for foreach() in...

[Tapio Markula]

Katja Lampela
> Hi all,
> 
> I was trying to check why installing the extension "Differentiated 
> formmail recipients" (julle_diffformmailrcp) caused the front end go 
> completely blank and I enabled in the install tool the sglDebug and 
> displayErrors.
> 
> 
> After de-installing the extension everything went back to normal and I 
> also compared the tables and everything is fine according to the install 
> tool.
> 
> Now - the error displaying still on, the weird thing happens: I get this 
> error message in the left BE frame top everytime I hit "Clear cache in 
> typo3conf":
> 
> *Warning*: Invalid argument supplied for foreach() in 
> */home/mydomain.com/html/typo3conf/temp_CACHED_ps4f0f_ext_tables.php* on 
> line *2675*

these kinds of warnings are not serious - just warnings.
Foreach expects to have multilevel array or single level array, which 
key value has been saved

> Everytime I hit "Clear FE cache" the error disappears and stays away 
> until I hit the "Clear cache..." again.

happens in some situation - in some situation the handled variable is no 
t handled properly.
> 
> Is this something I should worry and any idea what could cause this?
Usually those don't cause functionality failures. In order to avoid them 
around foreach loop could be conditions to check that foreach handles a 
proper array.