I've just tried applying a patch generated by IDEA with TortoiseSVN, both of which say they use the unified diff format, and am getting the following error:
"The line "Index: " was not found!
Either this is not a diff file or the diff is empty."
Looking at the format of the patch files generated by both applications, there is a noticable difference in that TortoiseSVN has an extra line of the following for every file which is part of the diff:
Having no knowledge of the unified diff format, is this a bug in IDEA or in TortoiseSVN?