I seem to remember the subject was discussed somewhere, but can't find the thread back. At the moment, we use the mirrorApp to mirror something like 10 public repositories (that's why I noticed and logged the bug about non-working merging feature that was corrected in the 3.5M3).
The mirroring works fine (still not using the merging, though). But there's a problem : when I add the mirrored repository URL to my eclipse installation where I deleted all other repositories entries, I always end up having many repositories listed from the net.
The thing is: in the end, we wan't our developers to declare a unique Eclipse P2 repository that they'll use to update or install "supported" software... And at the moment, they could download it from the net directly and obtain a version we didn't test...
I guess those URL comes from the already installed plugins/features. So, how could we wipe them out, or ignore them or proxy them through our mirror every necessary time (and stop new mirrors from appearing automatically in the update interface...).
Is this something considered possible with P2? If so, could you please let me know how to do that?