You can checkout, but you can not commit

time to read 2 min | 370 words

Well, here is how my last few days were spent. Trying to get SvnBridge to work on Mono 1.9.1. (Note that we are talking about working locally, when the hosted version will go live, it will obviously be accessible from everything and anything that can talk to an SVN server).

After getting it to compile and run (not a trivial process, I must say, I used a surprisingly high number of MS CLR stuff, but we will leave that to another post), I had managed to get some basic functionality working, and I was able to successfully checkout the source of SvnBridge itself.


Unfortunately, when I tried to commit those changes, I run into several... problems.

Without beating too much around the bush, the issue was that authentication errors against the TFS web service API. More specifically, in the error handling of those authentications errors.

In several parts of SvnBridge, we have code similar to this:

    return tfsWebService.DoSomething();
catch(WebException we)
    HttpWebResponse r = we.Response as r;
    if( r != null && r.StatusCode == HttpStatusCode.Unauthorized )
          throw new NetworkAccessDeniedException(we);       

The problematic part is bolded and in red. As I already mentioned, there is a subtle but incredibly annoying difference between Mono and .Net. This means that code such as this will never work. The issue is that the Mono implementation of HttpWebResponse check to verify that no access is done to a disposed object. Precisely like a well behaved object should. The .Net implementation does not.

By the time that the SOAP stack implementation (on both sides) gives you the web exception, the web response has been disposed. But on the Mono side of things, you can't even find out why.

As a result, I made up this logo.


I have reported the issue to the Mono guys, and hopefully they will get this fixed.