Could you add API documentation there what this signal indicates and when to use it? Typically, if you find code that is documented it is good practice to do the same :-)

Is it guaranteed, that this is emitted before IndexedDataRetriever job is finished?

I don't think so, because IndexedDataRetriever::start() does not block.

In that case it might be safer to do

       IndexedDataRetriever *ret = new IndexedDataRetriever(filePath, this);
	​connect(ret, SIGNAL(finished(KJob*)), this, SLOT(slotLoadingFinished(KJob*)));       
       
        insertBasicData();
	​insertEditableData();
	​emit dataAvailable();

​        ret->start();

Because once loadingFinished() is signalled it's over. dataAvailable(); won't get processed anymore.

Sounds good, but please explain why we are moving this signal in the commit message. This will make easier to git blame this code in the future.

test with empty items(): This code is reached, but the moc doesn't signal.