bug#37974: eww produces "error in process filter: Specified time is not representable"

["A.C." <achirvasub@gmail.com>]

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On October 29, 2019 5:52:02 PM EDT, Lars Ingebrigtsen <larsi@gnus.org> wrote:
>"A.C." <achirvasub@gmail.com> writes:
>
>>>In any case, Emacs 27 has bignum support, so this should hopefully
>not
>>>be a problem any more. Can you try the test case with the current
>>>Emacs
>>>trunk and see whether it's still present?
>>
>> That will be tough. This 32-bit machine overheats something fierce; I
>> doubt I can even clone the git repo without it dying, let alone
>> compile.
>
>Testing a bit more, the bug is present even on 64-bits systems.
>
>While this works:
>
>(format-time-string "%a %b %d %H:%M:%S %Y GMT" 9460800000000000 t)
>=> "Wed Apr 08 00:00:00 299802787 GMT"
>
>(format-time-string "%a %b %d %H:%M:%S %Y GMT" 94608000000000000 t)
>
>errors out with
>
>"Specified time is not representable"

Absolutely; I noted as much in the follow-up email to the one you cited above:

While 32-bit systems are vulnerable to the "year-2038 problem" 64-bit ones have an issue with year 

2147485548 = 1900 + 2**31

So you can only go up to

Wed Dec 31 23:59:59 GMT 2147485547

meaning the highest it'll run without error is

(format-time-string "%a %b %d %H:%M:%S %Y GMT" 67768036191676799 t)

As soon as you try

67768036191676800 = 67768036191676799 + 1

you'll get the 

"Specified time is not representable"

complaint.

>
>Test case:
>
>(url-cookie-handle-set-cookie "browser=68.133.6.220.1572324160979722;
>path=/; max-age=946080000000000000; domain=.arxiv.org")
>
>The input is completely controlled by the server, of course, and bogus
>data may appear in the cookie, and the URL library should protect
>against this, so I've now made it ignore these errors in Emacs 27. 
>This
>patch may also apply to the version of Emacs you're using; I haven't
>checked.
>
>diff --git a/lisp/url/url-cookie.el b/lisp/url/url-cookie.el
>index 31fc3e7266..740a43fa16 100644
>--- a/lisp/url/url-cookie.el
>+++ b/lisp/url/url-cookie.el
>@@ -304,9 +304,10 @@ url-cookie-handle-set-cookie
> 			 (url-filename url-current-object))))
> 	 (expires nil))
>     (if (and max-age (string-match "\\`-?[0-9]+\\'" max-age))
>-	(setq expires (format-time-string "%a %b %d %H:%M:%S %Y GMT"
>-					  (time-add nil (read max-age))
>-					  t))
>+	(setq expires (ignore-errors
>+                        (format-time-string "%a %b %d %H:%M:%S %Y GMT"
>+					    (time-add nil (read max-age))
>+					    t)))
>       (setq expires (cdr-safe (assoc-string "expires" args t))))
>     (while (consp trusted)
>       (if (string-match (car trusted) current-url)

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