Fix StackOverflowError in SemanticsMetadataProvider

[J-N-K]

In case of cyclic/recursive membership of groups (i.e. a group has itself or a child as parent) the recursive processing of the items leads to an StackOverflowError (reported in the forum and the german Facebook group). Also this is clearly a configuration error it should not result in the bundle not starting.

[wborn]

The fix looks good to me. 👍 Would it also be possible to add a unit test for this? Did you also consider using the warn loglevel? It is quite severe but I don't know if it is error level severe because the system can handle it.

[J-N-K]

I chose the same log level that is used here:

openhab-core/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/item/EnrichedItemDTOMapper.java

Lines 107 to 109 in 04105c1

	LOGGER.error(
	"Recursive group membership found: {} is both, a direct or indirect parent and a child of {}.",
	member.getName(), groupItem.getName());

[wborn]

Thank you for also adding the tests and log level explanation. 👍

[openhab-bot]

This pull request has been mentioned on openHAB Community. There might be relevant details there:

https://community.openhab.org/t/problem-after-upgrade/148149/14