When Expat calls the externalEntityRefHandler within
then it concludes that there must be an external
subset, as there
was an external identifier encountered.
This information influences how the WFC: Entity Declared
However, when Expat calls the externalEntityRefHandler
to allow the application to supply an external subset
was none, then Expat should not make this assumption unless
an actual subset has been processed, as indicated by the
The attached patch fixes this.