svn crashes when exporting a local checkout with root-relative svn externals

[Doug Brown]

Ubuntu 16.04, subversion 1.9.3-2ubuntu1

I have an SVN repository that has an svn:external that is relative to the root of the repository using the ^/ syntax. For example:

^/test.txt test2.txt

With this type of external, I'm running into a bug: I can't use svn export if I specify a particular svn revision with the -r option to the svn command. For example, if I type this command:

svn export -r 4 /home/doug/Downloads/myrepo-co/ myreportest4

It prints out the following error, and then crashes:

svn: /build/subversion-yttRtj/subversion-1.9.3/subversion/libsvn_subr/dirent_uri.c:322: canonicalize: Assertion `*src != '/'' failed.
Aborted (core dumped)

If I remove the -r 4 option, it doesn't crash and everything works perfectly.

ProblemType: Crash
DistroRelease: Ubuntu 16.04
Package: subversion 1.9.3-2ubuntu1
ProcVersionSignature: Ubuntu 4.8.0-58.63~16.04.1-generic 4.8.17
Uname: Linux 4.8.0-58-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.6
Architecture: amd64
CurrentDesktop: MATE
Date: Mon Jul 3 18:51:01 2017
ExecutablePath: /usr/bin/svn
ExecutableTimestamp: 1457943789
InstallationDate: Installed on 2017-07-04 (0 days ago)
InstallationMedia: Ubuntu-MATE 16.04.2 LTS "Xenial Xerus" - Release amd64 (20170215)
ProcCmdline: svn export -r 4 /home/doug/Downloads/myrepo-co/ myreportest4
ProcCwd: /tmp
Signal: 6
SourcePackage: subversion
StacktraceTop:
 raise () from /lib/x86_64-linux-gnu/libc.so.6
 abort () from /lib/x86_64-linux-gnu/libc.so.6
 ?? () from /lib/x86_64-linux-gnu/libc.so.6
 __assert_fail () from /lib/x86_64-linux-gnu/libc.so.6
 ?? () from /usr/lib/x86_64-linux-gnu/libsvn_subr-1.so.1
Title: svn crashed with SIGABRT in raise()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo

[Doug Brown (macg3)]

FYI, I reported this bug upstream a few days after reporting it here, and it has been fixed, but not released yet. It will be released in an upcoming version of Subversion 1.9.x. It would be great if the fix could be backported to 16.04. The fix is in these two commits:

http://svn.apache.org/viewvc?view=revision&revision=1802080
http://svn.apache.org/viewvc?view=revision&revision=1802316

[Doug Brown (macg3)]

The fix for this bug was released upstream in Subversion 1.9.9. It would be great if the fix could be ported into 16.04 and 18.04.