Doubled dates in old repositories

Hi,

we've got a report for an issue [322] where we're not sure how it
happened and if it happens often. As I know that some of you have many
and long standing repos, you might want to have a look before you
upgrade to 2.0.0. Also I'd like to know if the problem is unique (manual
intervention could have caused the issue) or generalized.

Basically, there are two entries with exactly the same date and time in
the repository, this shouldn't be and this makes rdiff-backup 2.0.0
choke on it (rdiff-backup 1.2/1.3 -actually Python 2- doesn't choke but
its reaction is unpredictable, which isn't really better).

How to detect (under Linux): run `cd MY_BACKUP_REPO; ls -1
rdiff-backup-data/mirror_metadata.* | sed -e 's/^.*mirror_metadata\.//'
-e 's/\.[a-z]*.gz$//' | uniq -cd` -> if the output is NOT empty, you
have the issue.

How to fix: delete with 1.2/1.3 the older entries in your repo(s) up and
including to the dates given by the previous command.

As said, small feedback to understand the extension of the issue would
be great. I'll work around the issue to make rdiff-backup 2 more robust
in this regard.

Thanks, Eric

[322] https://github.com/rdiff-backup/rdiff-backup/issues/322