W3C home > Mailing lists > Public > www-tag@w3.org > February 2010

Re: Backward-compatibility of text/html media type (ACTION-334, ACTION-364)

From: Dan Connolly <connolly@w3.org>
Date: Tue, 02 Feb 2010 10:28:18 -0600
To: "Henry S. Thompson" <ht@inf.ed.ac.uk>
Cc: www-tag@w3.org
Message-ID: <1265128098.3812.248.camel@pav.lan>
On Tue, 2010-02-02 at 15:06 +0000, Henry S. Thompson wrote:
> Hash: SHA1
> Dan Connolly writes:
> > On Tue, 2010-02-02 at 12:32 +0000, Henry S. Thompson wrote:
> >> Hash: SHA1
> >> 
> >> Three points:
> >> 
> >>  1) As Julian says, DOCTYPE is not the only issue;
> >> 
> >>  2) Ian Hickson's response appears to me to confuse two separate
> >>     issues -- we're not contesting that the HTML 5 spec can define
> >>     conformance as it currently does -- previous HTML specs have
> >>     eliminated features and ruled old documents non-conforming to the
> >>     new spec.  What's at issue is whether or not such documents can be
> >>     labelled 'text/html'.  Equating the class of "can be served as
> >>     text/html" with the class "conforms to this spec." is what we are
> >>     objecting to
> >
> > It is? I don't recall objecting to that.
> >
> > Given a suitable definition of "conforms to this spec", I think I'm
> > OK with equating it with "can be served as text/html".
> Sure, if the spec. is changed so that all past HTML docs conform to
> the it, but as I said, I don't think that's a reasonable requirement
> on this or any other spec.

I think I'd be happy with less than "all past HTML docs"...

> My understanding of the discontinuity wrt the text/html media type
> registration prose is this:
>  1) Previous media type registrations for text/html have explicitly
>     grandfathered in documents allowed by all earlier registrations of
>     text/html;

That was my understanding until I recently double-checked the

Published specification:
      The text/html media type is now defined by W3C Recommendations;
      the latest published version is [HTML401].  In addition, [XHTML1]
      defines a profile of use of XHTML which is compatible with HTML
      4.01 and which may also be labeled as text/html.
 -- http://www.ietf.org/rfc/rfc2854.txt

i.e. in June 2000, the IETF said goodbye HTML 2.0, which was
a proposed standard in 1995:

"The "text/html" Internet Media Type (RFC 1590) and MIME Content Type
   (RFC 1521) is defined by this specification."
 -- http://www.rfc-editor.org/rfc/rfc1866.txt

RFC 1866 now has status Status: HISTORIC
(per http://www.rfc-editor.org/rfcsearch.html , which... grumble...
uses POST where a GET would let me give you a link right to
what I want you to see...)

HTML 3.2 also went the way of the dodo, though I'm not sure there
was ever a follow-your-nose path from the text/html registration
to HTML 3.2.

>  2) IETF rules for media type re-registrations requires that sort of
>     grandfathering;

"require" is too strong; they _may_ reject an update if it fails
to sufficiently grandfather.

>  3) The current draft media type registration section of the HTML 5
>     spec. does _not_ contain any such grandfathering.

"any" is too strong; it contains grandfathering in the form
of "obsolete permitted DOCTYPE" (and perhaps other stuff I
haven't discovered).

Dan Connolly, W3C http://www.w3.org/People/Connolly/
gpg D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E
Received on Tuesday, 2 February 2010 16:28:21 UTC

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