GetFeatureInfo on a GROUP of layers should skip non queryable layers instead of producing exception

[dmorissette]

At the moment, if we do a GetFeatureInfo on a GROUP of layers in which at least one of the layers is not queryable, we get the following exception:

msWMSFeatureInfo(): WMS server error. Requested layer(s) are not queryable.

It would help if we could just skip the non-queryable layers that are part of a group. This would allow things like scale-dependent layers that are grouped together for presentation to have a single queryable layer for the whole group. I don't think the WMS specification forbids that, does it?

[dmorissette]

Patch against trunk that implements this

[dmorissette]

Assefa, does the attached patch seem okay to you? Do you think this change of behavior would break anything?

[assefa]

Daniel, I do not see any issue with this. The only thing I can see is if none of the layers in the group are queryable and we end up with numlayers_found == 0, the error message returned should be checked to reflect this.