Using the SVN task from tigris I can't seem to find a way to just commit one file. Is there any way to do this without first having to checkout the folder in SVN?
No. You cannot check in a single file w/o having a working copy which means you will have to checkout at least one directory.
Perhaps I don't fully understand, but you cannot check in a single file with the svn binaries so you certainly can't do it through ant.
This post has some information about committing a file with checking it out first. http://svn.haxx.se/users/archive-2007-06/0937.shtml
If you can also provide WebDAV access to the subversion repository, you could then use curl to upload a single file to the repository without having a working copy. You won't have a useful commit message, etc., so use with caution.
In svnant you can commit an unversioned file or tree into the repository with <import/>
task
put subversion/bin into your PATH and write own ant task like
<macrodef name="svn_call"> <attribute name="src.path" /> <attribute name="dst.path" /> <attribute name="command" /> <sequential> <exec failonerror="true" executable="${env.SVN_HOME}/bin/svn" osfamily="windows"> <arg line="@{command} @{src.path} @{dst.path}" /> </exec> <exec failonerror="true" executable="${env.SVN_HOME}/bin/svn" osfamily="unix"> <arg line="@{command} @{src.path} @{dst.path}" /> </exec> </sequential> </macrodef>