Before doing anything described here, please back up your workspace! I'm not talking about fetching that monster tape drive, install and run some huge backup software and then ship the tapes off to another continent - just make a copy somwhere of your Eclipse workspace. This so that you can start over, trying another angle, when things doesn't work out and your whole workspace is accidentially encrypted using your lavalamp's current formation as the key! (You then shut down Eclipse, delete your workspace, and "restore" the backup by copying it back. Start eclipse, and try your new approach.)
Before going further, first just attempt to start Eclipse with the "-clean" argument. You should not even need to worry about that backup then - and it might fix everything.
I have recently upgraded Eclipse to 3.4.0. I backed up my Workspace to some temp space, and then just pointed the new Eclipse to the same Workspace (the existing, "old" copy..). This magically worked nearly flawlessly: The Workbench looked exactly the same, all views set up the same, all Mylyn local tasks (which was the only type I had) was set up with contexts and everything.
But there were apparently some problems. The first one I don't quite remember, but Eclipse/Subversive at some point asked me if I wanted to reconnect to "the now-deleted repository location" something "https://blahabla...". And I then also noticed that all the Subversive markings (where you are (trunk), version numbers, colours, markings, whatevers you've configured Subversive to adorn your project with) were gone. I just said yes, and hoped for the best. Nothing happened. But after a reboot of Eclipse (I've found that much fixes itself by booting this application!), everything seemed to work.
But today, I wanted to commit something. This didn't work out at all, and in the Console window, I got "svn: authentication cancelled" and "blahblah Error". The annoying thing was that it just never asked me for credentials, so I couldn't give it my password (the username was saved, at least earlier). When this happened, Eclipse popped up a screen stating that some error had occurred (I don't remember the wording here, it was terse and useless), stopping up.
So, I did a couple of things which apparently seemed to work:
- Deleted "C:\Documents and Settings\<username>\Application Data\Subversion", based on this Oracle bug. You'll then be asked whether the certificate is correct etc etc upon next attempt to do Team->Update. Do note, however, that I don't think this is a part of the solution! So you may go ahead without doing this, at least the first round..
- Back up the project in question, in particular if you have heaps of uncommitted stash there! (If you don't have uncommitted data, you might just as well delete the entire project, and just start with a fresh checkout).
- Right-click on the problematic project -> Team -> Disconnect
- Choose "Do not delete the SVN meta-information (e.g. .svn subdirectories)", click Yes.
- After a while, you'll see that the project disconnects, and the Subversive markings disappears.
- Now, you go Right-click -> Team (Don't freak out by this menu being pretty much empty!) -> Share Project...
- Pick SVN (Obviously), click Next
- Pick the "Create location using project settings" (second choice here).
- You'll come to the "Enter Repository Location Information" page.
- At this point, the one thing that I immediately noticed, was that it suggested URL "https://blahblah/svn/<projectname>/trunk". I don't think the "trunk" part shall be a part of the location, so I removed it.
- Check the "Validate Repository Location on finish".
- Enter your username and password. I don't want to store the password, so I leave "Save password" unchecked.
- You may at that point click the "Browse" button to check if your URL is good - it should show the "branches", "tags", "trunk" directories.
- On the Advanced tab, check "Enable Structure Detection".
- I don't have anything fancy for the SSH Settings nor SSL Settings.
- When I clicked Finish, the Subversive markings reappeared, everything worked, and I could update and commit right away!
- Note that the repository location, which you may enable the project name node to be adorned with by Subversive, reads "https://blahblah/svn/<projectname>", leaving out the "trunk" part. The full text on my project name node is "[https://blahblah/svn/<projectname>: trunk]" - but this isn't standard config for Subversive, I believe.
Actually, I have ended up with something rather like this once before: I didn't know what URL Subversive wanted, so I navigated using the browse button, and navigated all the way into the "trunk" directory, as it was trunk I wanted to check out and work with, and I didn't immediately see any other way to select that. Subversive is seemingly quite happy with this, checking out your project and whatnot. But then, later in the game, things start to weird out. I don't quite remember how this manifested itself, but I do remember that I got some strange recursion problem, where I could see the entire trunk/branch/tags structure within my project. When I realized the URL thing, deleted the project and started anew, everything cleared up.
I think Subversive should be nice enough to point out that you've most probably navigated wrongly now, as the latter part of the SVN URL is at this point looks like a "known structural ending", and this should not be a part of the URL blah blah. See, Subversive does know what the standard structure of a SVN setup is - so it could easily have done this. I filed a bug about this (a year or so ago), but so far nothing have happened.
Update 2008-09-08: I got the same problem again some days ago. Subversive doesn't use the normal Preferences screen to define subversion repositories. It has its own view, called "SVN Repositories" (in the same way that Mylyn has "Task Repositories"). Here you can find the different repositories. Right click, and select "Location Properties..." (Not "Show properties", as that refers to subversion properties; Those things that you can stick on directories and files within the repo, e.g. "svn:ignore" @ trunk). Hitting the Location Properties, you get that Edit Repository Location dialog which I refer to in the above hundred or so bullets. If you here click the Browse button, you will get a username/password dialog (given that they aren't correct on the parent dialog). You should be able to browse the repository. When this works, stick in the username/password in the Edit Repository Location dialog again, tick off "Validate Repository Location on Finish", and hit the "Finish" button. The authentication problem is now gone.
In addition, I believe I might still be mistaken about what URL the location should be. I have now changed it to not include the <projectname> part as I stated above, as the URL without that part would be the location to the actual Subversion repository. This seems more logical (and it still works!).
Furthermore, after a couple of those "svn: authentication cancelled" rounds, I tried starting eclipse with the "-clean" argument. I have not had the problem afterwards. Whether it was the location URL, or the -clean that finally fixed it, I am not sure about, although I tend to believe the latter.
Finally, it is actually also possible to completely disconnect from the repository (Team->Disconnect), choosing "Also delete the SVN meta-information from the file system" from the Confirm Disconnect from SVN dialog. You can then Team->Share, make a new repository location, and from that pick the same project you have the files for. Subversive apparently realizes that the project name you try to share it as, already has information in it, and apparently checks it out at a temp location, then copy back the files, seemingly keeping your changes. I would however not bet on that - this really seems just as risky as to start afresh with a new checkout of the project. In any case here, back up your workspace before trying anything!!