QGIS » QGIS Application

- enable relative save paths in the project settings
- load some layers from a zip file
- save the project in the same folder as the zip file
- rename the folder
- open the project
You will get the dialogue asking you to specify the paths of the "missing" layers.
- open the project file in a text editor and change the paths used for the vsizip layers to relative paths.
- open the project
The layers will still be "missing", so it seems the vsizip driver does not support relative paths.

Problem 1: the vsizip layer driver should ideally support relative save paths. (N.B. I'm testing on a Windows system and I can get the vsizip functionality to work with ogrinfo and gdalinfo in a dos terminal with either absolute or relative paths, but I can't figure out how to get it to work in an msys rxvt terminal with absolute paths...)

Problem 2: in the dialogue asking you to specify the paths to "missing" layers, if you correct the "path" for the vsizip layer, the dialogue doesn't recognise it as valid - it only recognises a simple path.

N.B. there are other issues with the dialogue, e.g. even if the path to a layer referred to a folder (instead of a file), the fileselector only allows you select a file (not a folder). But you can manually type the path to a folder and the dialogue correctly recognises it as valid.