Avoid Resource.meta.source string matching an illegal fragment

[MartinBernstorff]

When creating a resource, if no Resource.meta.source is provided:

Source has the form: < Source URI >#< request ID >.

https://smilecdr.com/docs/fhir_repository/tracing_and_provenance.html#request-tracing

However, if the SourceURI is blank, that means it'll have the form #<requestID> which looks like a fragment, i.e. a reference to a contained resource. Therefor, resource validation will fail. We see this on our running server.

Likely a related issue: #6960

To avoid this, if the <SourceURI> is blank, we no longer prefix with #. I am not convinced this is a good solution.

Alternatives

• The resource validator could avoid checking for fragments in Resource.meta.source
• We could infer, or require, a theProvenanceSourceUri
• We could avoid setting the Resource.meta.source if theProvenanceSourceUri is empty