Given following SVNRoot content:

# BEGIN CODENDI DEFAULT SETTINGS - DO NOT REMOVE
[groups]
members = vaceletm


[/]
* = r
@members = rw
# END CODENDI DEFAULT SETTINGS
[/]
* =
@members = r
# @Integrators = rw

[/trunk]
# @Contributors = rw

This gives the following error:

2023-04-03T11:57:31+02:00 [322] [error] ViewVC error in #/svnplugin/e2e-svn-01/sample at #/:
Traceback (most recent call last):
  File "/usr/lib/python3.9/site-packages/viewvc/lib/vcauth/svnauthz/__init__.py", line 66, in _get_paths_for_root
    cp.read(self._get_authz_file(rootname))
  File "/usr/lib64/python3.9/configparser.py", line 697, in read
    self._read(fp, filename)
  File "/usr/lib64/python3.9/configparser.py", line 1070, in _read
    raise DuplicateSectionError(sectname, fpname,
configparser.DuplicateSectionError: While reading from '/var/lib/tuleap/svn_plugin/232/sample/.SVNAccessFile' [line  9]: section '/' already exists

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/share/tuleap/plugins/svn/include/SVN/ViewVC/../../../bin/viewvc-master.cgi", line 49, in <module>
    if tuleap_user_is_super_user != '1' and not svnaccess.check_read_access(username, repo_path, requested_path):
  File "/usr/share/tuleap/src/utils/svn/svnaccess.py", line 28, in check_read_access
    return __check_read_access_with_epel_viewvc(username, svnrepo, svnpath)
  File "/usr/share/tuleap/src/utils/svn/svnaccess.py", line 35, in __check_read_access_with_epel_viewvc
    return authorizer.check_path_access(svnrepo, requested_path_parts, None)
  File "/usr/lib/python3.9/site-packages/viewvc/lib/vcauth/svnauthz/__init__.py", line 277, in check_path_access
    paths = self._get_paths_for_root(rootname)
  File "/usr/lib/python3.9/site-packages/viewvc/lib/vcauth/svnauthz/__init__.py", line 68, in _get_paths_for_root
    raise ViewVCException("Unable to parse configured authzfile file")
common.ViewVCException: ViewVC Unrecoverable Error: Unable to parse configured authzfile file

This corresponds to the following change in svn 1.10: https://subversion.apache.org/docs/release-notes/1.10.html#authz-compatibility

In addition to the problem of duplication of the path definition, there is also a problem with the group/user definition for any given path. As stated in the release note:

The 1.9 and earlier implementations allowed multiple entries matching the same name, alias or group and the last match applied:

 [/some/path]
 user = rw
 user = r
 &alias = rw
 &alias = r
 @group = rw
 @group = r

In 1.9 the final, read-only, match for user, &alias and @group would be selected while 1.10 combines all the lines to give read-write access

So it means that projects could exposes private content at upgrade without prior notice.

This is a particularly tricky situation but, fortunately it only really exposes platforms that migrates from el7 to el9, no new platforms.

The proposed solution is the following:

1. [x] Add an option (off by default) to disable the default permission set by Tuleap on /
2. [x] Check SVNAccessFile for duplicate path definitions (so admins can preventively adujst the permission schemes)
3. [x] Check SVNAccessFile for duplicate user/group permissions (idem)
4. [] Give a tool to identify projects/repo that have issues with 2 & 3 with a way for site administrator to track them before upgrade (+ warn & notify affected people)
5. [] On el9, there should be a validation of the SVNAccessFile to ensure that the result will be valid