I messed up and did the main development on a branch, the trunk is actually empty in the repository and I'm trying to move the branch to the trunk.
I'm not sure how this is supposed to be done the right way and it gets more complicated because in my project I also have a lot of externals.
I'm using TortoiseSVN and I tried to switch over to the Trunk and it deleted all my files (makes sense since the trunk is empty).
Then I tried to do a merge from the branch to the trunk but I get the message "Cannot merge automatically while ignoring mergeinfo".
What is the proper way to fix this "mess", all I want is to move the branch I have been working on all the time to the trunk.
I solved it.
In the repository browser I simply just marked all the files and folders inside my branch and moved them (drag & drop) into the trunk folder (in the repository).
Then I just did an update in my working folder (I had already done the switch from branch to trunk before).
It was that simple!
EDIT
I think the problem was that my "branch" copy was not created with the Branch/tag command. It was a check out directly from repository branches.