bug#29116: 24.5; Parsing dates from VCAL

[Robert Pluim <rpluim@gmail.com>]

Vegard Vesterheim <vegard.vesterheim@uninett.no> writes:

> I received an email containing a VCAL attachment which Gnus is unable to
> render, the error in the minibuffer says:
>
>   Wrong type argument: char-or-string-p, nil
>
> The VCAL-attachment contains this:
>
>     DTSTART;VALUE=DATE:20171208
>
> The spec for DTSTART states that the value type for DTSTART can be
> either DATE-TIME or DATE, so this seems like a valid format, so I am
> inclined to think that this is a bug in emacs.

Yes, it's allowed, but annoying.

> Here is the backtrace (parameters removed 
>   timezone-make-arpa-date(2000 0 0 "01:00:00" (3600 "CET"))
>   timezone-make-date-arpa-standard("20171208" nil nil)
>   gnus-icalendar-event--decode-datefield(...)
>   gnus-icalendar-event-from-ical(...)
>   gnus-icalendar-event-from-buffer(...)
>   gnus-icalendar-event-from-handle(...)
>   gnus-icalendar-mm-inline(...)
>   mm-display-inline(...)
>   mm-display-part(...)
>   gnus-mime-display-alternative(...)
>   gnus-mime-display-part(..)
>   gnus-display-mime()
>   gnus-article-prepare-display()
>   gnus-article-prepare(94599 nil)
>   gnus-summary-display-article(94599)
>   gnus-summary-next-article(nil)
>
> Looking at the backtrace it seems that the problem is related to parsing
> the date string: "20171208".

timezone-parse-date assumes that the time-of-day is present in the
string to be parsed, which is not the case here. Looking at the code
icalendar should set the time to "00000" in that case. Would you have
a complete example VCAL file?

Thanks

Robert