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

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

[Matthew Carter]

Excuse the new thread (just signed up to bug-gnu-emacs list, whereas I
filed the original bug via the report function).

I've pinpointed the eww-mode bug to an issue with #'date-to-time in
time-date.el.

It appears to be a manifestation of the Year 2038 problem and caused by
the fact that the cookie being sent has an expiration date beyond year
2038.

As it turns out, I am unable to reproduce the issue on a 64-bit machine
(it only happens on my 32-bit ones).

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?

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

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

[Paul Eggert]

> 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?

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

[Matthew Carter]

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

bug#19798: 24.4; eww-mode error in process sentinel 'Invalid date' when receiving a valid date

[Paul Eggert]

I reproduced this bug on Fedora 21 i686.  I looked at the current master and 
fixed some relevant issues, in commit fd6f7d1449c8496ab5c019d2aad7ca5e2980713a 
dated today.  I then attempted to reproduce the bug but failed, so it appears 
that the bug is fixed now in the current master (either by the recent fixes, or 
by earlier fixes in the master).  Please give it a try.

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

[Paul Eggert]

OK, I've fixed the "Invalid date:" bug in master commit 
fd6f7d1449c8496ab5c019d2aad7ca5e2980713a dated today.  This fixes the problem 
with date-to-time on 32-bit hosts, since it now throws the correct exception 
rather than the incorrect one, so I'm closing this bug report.  I'm leaving 
Bug#19798 open for now, until you can verify that the original eww issue is 
indeed fixed on the master.

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

[Matthew Carter]

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

> OK, I've fixed the "Invalid date:" bug in master commit
> fd6f7d1449c8496ab5c019d2aad7ca5e2980713a dated today.  This fixes the
> problem with date-to-time on 32-bit hosts, since it now throws the
> correct exception rather than the incorrect one, so I'm closing this
> bug report.  I'm leaving Bug#19798 open for now, until you can verify
> that the original eww issue is indeed fixed on the master.
>
>
>

The issue is fixed, no more failure to load subsequent pages when an
overflowed cookie date is encountered.

Thanks!

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

bug#19798: bug#19799: Tangentally related to eww-mode Invalid Date bug just filed

[Paul Eggert]

Matthew Carter wrote:

> The issue is fixed, no more failure to load subsequent pages when an
> overflowed cookie date is encountered.

Thanks for checking, and so I'm closing Bug#19798 too.