TYPO3 Core

UserInternalContentObject is trying to serialize ContentObjectRenderer.
This leads to severe issues also uses lots of memory.

If you set up a page like this

page = PAGE
page.10 < styles.content.get
page.20 < plugin.tx_felogin_pi1

Install sysext:felogin and add static templates for CSC and felogin!

Add a "text w/image" CE to the page and add at least one image.

you'll get an Exception in FE: Serialization of closure not possible.

(In order to see the Exception you need to set the application context to Development and select the Development-preset in Install Tool.)

The reason is that if the Core is not installed via composer, a closure is registered in the SignalSlotDispatcher.
For some reason, when serializing ContentObjectRenderer, also SignalSlotDispatcher is serialized, which leads to this exception.

The solution is to remove the "hard-wires" between ContentObjectRenderer and TSFE and File(Reference).