option to fail a read if not all series are found

[HomoCodens]

In a couple of projects now I've seen code fail after a db_ts_read(con, some_keys) because not all series in some_keys are present in the resulting list.

Rather than have each piece of code that relies on all series being read having to do a check we could add a "fail_if_missing" kind of option to db_ts_read that stops with a meaningful error if not all the requested keys can be read (because of access rights, release dates, missing altogether etc.).

[HomoCodens]

Or alternatively at least always give a warning so the error is easier to track down.

[omuelle]

Yes, I had similar issues. At least a warning would be nice. The reason should be given, e.g. insufficient access rights.