Comment 8 for bug 1666495

Trevinho disagrees with me, but I want to put on the record that I think comment #6's patch is wrong and that instead the VACUUM mode should explicitly check if the database exists and "return 0" in that case.

Rationale:

It's reasonable to say that it's okay to run without having run the main program first. The counter argument says that this is *not* reasonable and you would expect an error in this case. I think that there is no one true way here, and you should write programs with their intended usage in mind. In this case I think the intented use is that you could imagine a user writing a shell script such as:

  #!/bin/sh

  set -e

  zeitgeist-vacuum # or zeitgeist --vacuum
  zeitgeist

(of course this is a simplified version of the existing user unit's control flow)

and it's just silly to have to detect the DB not existing explicitly there. It's also a bit shady to ignore VACUUM failures that could point to a more severe problem.

For the record, I think the code to implement my change would look like this (untested).

    var file = File.new_for_path (db_path);
    if (!file.query_exists ())
    {
        debug ("Database '%s' doesn't exist, but that's okay".printf (db_path));
        return 0;
    }

With this change the unit file can remain unmodified.

Since there's disagreement, I won't unilaterally upload my suggestion.