$ svnadmin create repo
$ svn co file://`pwd`/repo wc
Checked out revision 0.
$ svn mkdir wc/trunk
$ svn ci wc -mm
Committed revision 1.
$ svn diff --summarize file://`pwd`/repo -c 1
$ svn diff --summarize file://`pwd`/repo/trunk -c 1
Note that trunk is repeated on the second summarize command. This is because the trunk does not exist in r0 so the editor drive is
the rooted at the root of the repository. As such the reported path is "trunk" and the code in the summarize_function combines the
URL with the reported path and trunk gets repeated.
This is related to issue #2765 which is the same problem except for a file. However at the time that bug was fixed this problem was
not possible because the requested path had to exist in both revisions. Issue #2873 solved that and allowed this situation to exist.
1.8.x and newer are not impacted because when diff --summarize was rewritten to function with not just two repos paths this issue
was fixed as a side effect.