It appears that TortoiseSVN (TortoiseMerge) requires the line Index: foobar.py
in the diff/patch file. This is what I needed to do to make a non-TortoiseSVN patch file work with TortoiseSVN's right-click Apply Patch command.
Before:
--- foobar.py.org Sat May 08 16:00:56 2010
+++ foobar.py Sat May 08 15:47:48 2010
After:
Index: foobar.py
===================================================================
--- foobar.py
+++ foobar.py (working copy)
Or if you know the specific revision your contributor was working from:
Index: foobar.py
===================================================================
--- foobar.py (revision 1157)
+++ foobar.py (working copy)