[PATCH, svnmerge] Fix spurious crash in "svnmerge init"

[Giovanni Bajo <ra...@develer.com>]

Hello,

When setting up a tree for use with svnmerge, svnmerge can optionally
extract the branchpoint of the branch (as a feature for the user). To do
that, it parses the output of "svn log --xml" with regular expressions
(ewww). It's a straight conversion from what the old bash script used to do:
one day I should rewrite this piece of code to use a proper XML parser to
avoid such quirks...

Anyway, the regex parsing is a little weak in that it sometimes matched the
copy-from attribute in a single file, rather than that of the whole
directory. This led to a crash later when trying to further process that
information. This patch fixes this crash by improving the error-recovery. It
could still happen that svnmerge is confused and can't extract the
information even if it is available: this will be fixed with the XML parser.

BTW, this had to be a pretty common bug as a I got several different
reports... It's now fixed in r18010.

[[[
Improve tree's copy-from revision extraction from "svn log --xml" output.
Avoid being fooled by copy-from information in single files.

* contrib/client-side/svnmerge.py:
  (get_copyfrom): Improve error-recovery.
]]]
-- 
Giovanni Bajo