bug#19799: Tangentally related to eww-mode Invalid Date bug just filed

[Matthew Carter <m@ahungry.com>]

Paul Eggert <eggert@cs.ucla.edu> writes:

>> Would it be better to rework #'date-to-time to handle future dates in a
>> more graceful manner on 32-bit machines, or to have eww-mode ignore
>> triggers that cause it to parse dates it cannot handle?
>
> There is a variant of date-to-time that refuses to throw an error on
> out-of-range dates, namely safe-date-to-time.  But I'm still puzzled
> as to why you're getting this error.  date-to-time is supposed to
> throw a "Specified time is not representable" for out-of-range dates,
> but for you it's throwing some other error.  Can you debug why that is
> happening?
>
> What happens when you run the following in your *scratch* buffer?
>
> (date-to-time "Mon, 06 Mar 2130 20:55:03 GMT")
>
> On my platform (Fedora 21 x86) if I type C-j after that, the debugger
> is entered with this backtrace:
>
> Debugger entered--Lisp error: (error . "Specified time is not representable")
>   signal(error "Specified time is not representable")
>   apply(signal (error "Specified time is not representable"))
>   (if (equal err overflow-error) (apply (quote signal) err) (condition-case err$
>   (let ((overflow-error (quote (error "Specified time is not representable"))))$
>   (condition-case err (apply (quote encode-time) (parse-time-string date)) (err$
>   date-to-time("Mon, 06 Mar 2130 20:55:03 GMT")
>   ...
>
> What happens on your platform?
>
> Also, what is your platform?  What does (emacs-version) return, for starters?
>

This is on an i686 machine - the eval returns:

Debugger entered--Lisp error: (error "Invalid date: Mon, 06 Mar 2130 20:55:03 GMT")
  signal(error ("Invalid date: Mon, 06 Mar 2130 20:55:03 GMT"))
  error("Invalid date: %s" "Mon, 06 Mar 2130 20:55:03 GMT")
  byte-code("\300\301\302\217\207" [nil (byte-code "\301\302\303\304^H!!\"\207" [date apply encode-time parse-time-string time$
  date-to-time("Mon, 06 Mar 2130 20:55:03 GMT")
  eval((date-to-time "Mon, 06 Mar 2130 20:55:03 GMT") nil)
  eval-last-sexp-1(t)
  eval-last-sexp(t)
  eval-print-last-sexp(nil)
  call-interactively(eval-print-last-sexp nil nil)
  command-execute(eval-print-last-sexp)

The version is:

GNU Emacs 24.4.1 (i686-pc-linux-gnu, GTK+ Version 3.14.7) of 2015-01-17 on bisson

Anything up to 2038 will work without issue.  I had read OpenBSD fixed
the 2038 date issue using 'long long int' instead of 'time_t' for dates
in the codebase on 32 bit machines.

I think eww-mode should not fail to load subsequent pages though, even
if a cookie date is bad (bad cookies should not halt further page
requests), so maybe eww-mode just needs to catch the thrown error?

-- 
Matthew Carter (m@ahungry.com)
http://ahungry.com