[YANGTOOLS-1336] Improve SchemaInferenceStack diagnostics

Relates — Wed, 6 Oct 2021 11:02:32 +0000

When we fail to lookup a data tree child, we provide very little context, as evidenced here:

Caused by: java.lang.IllegalArgumentException: Data tree child (urn:ietf:params:xml:ns:yang:ietf-restconf)operations not present
	at org.opendaylight.yangtools.yang.model.util.SchemaInferenceStack.lambda$pushData$5(SchemaInferenceStack.java:799) ~[?:?]
	at java.util.Optional.orElseThrow(Optional.java:408) ~[?:?]
	at org.opendaylight.yangtools.yang.model.util.SchemaInferenceStack.pushData(SchemaInferenceStack.java:798) ~[?:?]
	at org.opendaylight.yangtools.yang.model.util.SchemaInferenceStack.pushFirstData(SchemaInferenceStack.java:807) ~[?:?]
	at org.opendaylight.yangtools.yang.model.util.SchemaInferenceStack.pushData(SchemaInferenceStack.java:787) ~[?:?]
	at org.opendaylight.yangtools.yang.model.util.SchemaInferenceStack.enterDataTree(SchemaInferenceStack.java:473) ~[?:?]
	at org.opendaylight.yangtools.yang.data.util.NormalizedNodeStreamWriterStack.enterDataTree(NormalizedNodeStreamWriterStack.java:187) ~[?:?]
	at org.opendaylight.yangtools.yang.data.util.NormalizedNodeStreamWriterStack.startContainerNode(NormalizedNodeStreamWriterStack.java:259) ~[?:?]
	at org.opendaylight.yangtools.yang.data.codec.gson.JSONNormalizedNodeStreamWriter.startContainerNode(JSONNormalizedNodeStreamWriter.java:305) ~[?:?]
	at org.opendaylight.yangtools.yang.data.api.schema.stream.NormalizedNodeWriter.wasProcessedAsCompositeNode(NormalizedNodeWriter.java:204) ~[?:?]
	at org.opendaylight.yangtools.yang.data.api.schema.stream.NormalizedNodeWriter.write(NormalizedNodeWriter.java:102) ~[?:?]
	at org.opendaylight.netconf.sal.rest.impl.RestconfDelegatingNormalizedNodeWriter.write(RestconfDelegatingNormalizedNodeWriter.java:38) ~[?:?]
	at org.opendaylight.netconf.sal.rest.impl.RestconfDelegatingNormalizedNodeWriter.write(RestconfDelegatingNormalizedNodeWriter.java:19) ~[?:?]
	at org.opendaylight.netconf.sal.rest.impl.NormalizedNodeJsonBodyWriter.writeNormalizedNode(NormalizedNodeJsonBodyWriter.java:149) ~[?:?]
	at org.opendaylight.netconf.sal.rest.impl.NormalizedNodeJsonBodyWriter.writeTo(NormalizedNodeJsonBodyWriter.java:101) ~[?:?]
	at org.opendaylight.netconf.sal.rest.impl.NormalizedNodeJsonBodyWriter.writeTo(NormalizedNodeJsonBodyWriter.java:57) ~[?:?]

This makes it hard to discern where in the statement tree the failure occurred. In this particular case, the problem seems obvious, we are doing a 'pushFirstData', hence we are in the wrong initial context.

Improve error logging by including at least current statement, or perhaps a shorthand (like a new Inference.toString() method) to describe the state we are in.

OpenDaylight JIRA

[YANGTOOLS-1336] Improve SchemaInferenceStack diagnostics