Handle 'inbuilt:' vector uri

[rduivenvoorde]

This is take 2 to make it possible to use the inbuilt-vector data (world map etc) to be used in PyQGIS etc:

iface.addVectorLayer('inbuilt:/data/world_map.gpkg|layername=countries', 'Countries', 'ogr')

First take was: #39175 There @nyalldawson proposed to do it not ogr-specific but on a higher level. This is my first attempt to do it as he described there: #39175 (review)

Not sure if that was what he meant. I think more code has to get rewritten here (as for example now a inbuilt-uri WITHOUT layername-part will not load AND not popup the 'choose layer dialog', because the vectorLayerPath is const...
Should I create a copy of it and use that in the whole function?
Or am I totally wrong anyway.

One argument why I like #39175 actually better is that (untill now) inbuild is only used with OGR provider (and it is/was a oneline change). But feel free to disagree/comment or stop me from trying :-)

Also note that my proposed plan B in #39175

iface.addVectorLayer(QgsApplication.pkgDataPath() + '/resources/data/world_map.gpkg|layername=Countries', '', 'ogr')

actually does not work on Linux distro installs, because the gpkg in the resource is not readable by the average user apparently.

[rduivenvoorde]

Thanks @nyalldawson this is what it should be. Now I understand better your reasoning. And also removing the "|layername=countries" from the uri results in he 'choose layer' popup!
If tests pass, is this something to be backported into 3.16?

[rduivenvoorde]

I'm looking into adding a python test (for the inbuilt: uri), but wondering where to put it...

[nyalldawson]

I'm looking into adding a python test (for the inbuilt: uri), but wondering where to put it...

There's no real infrastructure in place for unit test QgisApp methods.