Can multiple users commit to SVN simultaneously? Is it thread safe?

Question

The application must be desgined in such a way that it must support multiple users while commiting into SVN Repositiry. I'm done with the application and the related stuff, however, i'm stuck with this multi-user thing. How i can achieve this? I saw somewhere that for every thread you have to instantiate a separate SVNRepository driver. This tell it's not thread safe..or may be i'm getting the whole thing wrong. Any help on this issue is appreciated. thanks.

I get the above info (the one in italics) from Here .

Answer 1

I'm SVNKit developer, let me explain how the things work.

SVNRepository class represents one SVN connection with it's own credentials. It is thread-unsafe that means that you can perform only sequential operations on it. See this article for more details:

http://vcs.atspace.co.uk/2012/09/21/are-svnkit-methods-reenterable/

So if your application tries to create several commits at the same time, you should use several independent SVNRepository instances. Good news is that no special synchronization code is required, all synchronization is performed on the server side. Another good news is that when commit for a certain SVNRepository object is finished or cancelled, you can reuse the connection to start another commit. But note that if you use http protocol, you can't reuse the same connection to commit on behalf another user even if you change credentials for the connection (SVNRepository#setAuthenticationManager).

To create a commit without working copy use SVNRepository#getCommitEditor which starts the commit transaction. To stop the transaction use either ISVNCommitEditor#closeEdit or ISVNCommitEditor#abortEdit; you can perform other operations on SVNRepository instance, until commit transaction is finished.

ISVNCommitEditor instance should describe your virtual working copy: it tells to SVNKit about your current knowledge of the latest working copy state. If the description doesn't correspond to the real latest change you get "File or directory is out of date; try updating" error.

http://vcs.atspace.co.uk/2012/07/20/subversion-remote-api-committing-without-working-copy/

You can use -1 instead of real revision in ISVNEditor#openFile/openDir to disable checks, but that can cause another problem: you could overwrite changes without knowing about them.

Another option is to commit using real working copies and real changes on filesystem (using SvnOperationFactory#createCommit). But even in this case have a look at the first link to learn which objects can/can't be reused across threads.

Hope this helps, if you have other questions, feel free to ask on SVNKit mailing list.