W3C

Results of W3C XML Plenary

Ballot on relative URI References

In namespace declarations

3-17 July 2000

Dave Hollander

C. M. Sperberg-McQueen

6 September 2000

1. Introduction

This document reports the results of an email ballot taken among members of the W3C XML Plenary Interest Group during the period 3-17 July 2000.

2. Purpose

The primary purpose of the ballot was to determine whether there is consensus in the plenary in favor of the proposal outlined below. A secondary purpose was to document the thinking of the plenary on these issues, so that WGs who are dealing with these issues can understand the plenary's rationale.

3. Conclusions

By a large margin, the XML Plenary endorses the proposal given below. A number of organizations (both some those who find the proposal acceptable and some of those voting otherwise) believe that the W3C should proceed to develop a longer-term solution by means of the normal WG process.

There are 73 (seventy-three) organizations with representatives in good standing on any WG of the XML Activity, the XSL WG, or the DOM WG, and individuals serving as invited experts on one or more of these WGs. Counting the ballots of these organizations and individuals, the net result is:

Of the votes in the first category, 35 were votes of 'acceptable', and 12 were votes of 'concur'. Of the abstentions, four were explicit and the remainder implicit (i.e. no ballot was cast).

In addition, three ballots were cast by organizations or individuals not recognized by the chairs of the Plenary as being in good standing on any of the named Working Groups. These ballots did not affect the net result.

4. The question

4.1 Chairs' message

[The following message was sent to the XML Plenary mailing list by the chairs on 3 July 2000.]

As members of this group will know, all the working groups in the XML Activity, as well as many individuals in the Web community at large, are currently bedeviled by the problem of how to interpret namespace declarations whose values take the form of relative URI references.

In spite of the earlier discussion of this in the XML Plenary, the straw poll taken by the XML Plenary in April, and a month of discussion on the xml-uri list, we have not yet resolved the issue. A number of specifications are in limbo, unable to move forward until we as a consortium reach a commonly accepted decision on this question.

In the long term, we believe most people would agree, the consortium needs a clear and coherent approach to the complex of problems of which the 'relative-URI-reference-in-NS-declaration' problem is a visible example. In the short term, we need an approach that everyone can live with, that avoids foreclosing later long-term solutions as far as is possible, and that will allow the various specs now in limbo to move forward.

Recent discussions in the xml-uri list suggest that a proposal originally made by Joe Kesselman and then elaborated by others may provide an approach everyone can live with. We are grateful to all those who have participated in the effort to clarify and resolve this issue for their work. If everyone, or almost everyone, can live with this solution, at least for the short term, then it may break the logjam. Some members of the XML Plenary have requested that we, as chairs, ask the Plenary to consider this question again, and see what kind of consensus we now have on this issue.

Since a resolution of this problem seems to grow more urgent by the week, we believe the progress of the XML Activity will be best served if we put the question to the XML Plenary.

The technical content of the proposal is outlined below. Since it is clear that there is not now unanimity on this question, we have agreed with the Director and management of the W3C that it is desirable for us to put the question to a vote in the Plenary.

If the Plenary decides in favor of the proposal, Working Groups preparing new specs will be advised to make those specs agree with the Plenary decision. (As always, the final decision on what a WG does rests with the WG, not with the Plenary: the Plenary decision is only advisory.)

If the Plenary does not decide in favor of the proposal, the status quo will remain unchanged.

We will send, in a separate message, a ballot to the XML Plenary list, asking each member organization to indicate whether the organization finds the technical proposal outlined below acceptable or not acceptable. Free-form comments on the question may also be included, providing a rationale for the ballot. Ballots are to be returned to the address specified on the ballot, by the time indicated on the ballot for the close of balloting.

The chairs will hold that the XML Plenary has decided in favor of the proposal if (a) at least half the qualified organizations cast a ballot of 'acceptable', and (b) at least twice as many organizations cast ballots of 'acceptable' as cast ballots of 'not acceptable'. Organizations may also vote to concur with the majority, in which case their ballots will be counted with the majority.

Any organization which is represented on any of the following Working Groups as of 1 July 2000 may cast a ballot on this question, as may invited experts serving on these WGs: XML Core, XML Linking, XML Schema, XML Query, XSL, DOM.

One ballot will be counted per organization. If conflicting ballots are received, without clarification, the chairs will count the organization as having abstained.

-C. M. Sperberg-McQueen
Dave Hollander
Co-chairs, W3C XML Plenary IG

4.2 Proposal

Proposed: to deprecate the use of relative URI references in namespace declarations; that is: to say that while they conform to the Namespace Recommendation of January 1999, later specifications such as DOM, XPath, etc. will define no interpretation for them.

In particular, regarding the following documents, one at http://example.com/pathSeg/thisDoc.xml: 

     <a:aDoc xmlns:a="../foo" 
             xmlns:b="http://example.com/foo"
             a:a='1' 
             b:a='2'/>

and another at http://example.org/pathSeg/thatDoc.xml: 

     <aDoc xmlns="../foo"/>

Q1:do they conform to XML 1.0?

A1: Of course; no one suggests otherwise. They are both well-formed.

Q2:Do they conform to the namespaces spec?

A2: Yes.

However, both documents use relative URI references in namespace declarations, which is deprecated.

The XML Core WG is advised to publish a notice (perhaps at http://www.w3.org/XML/xml-names-19990114-errata) that the use of relative URI references in namespace declarations is deprecated.

Q3:But I thought that ../foo and http://example.com/foo meant the same thing in the context of the base URI http://example.com/pathSeg/thisDoc.xml

A3: Even though per RFC 2396 the relative URI reference ../foo denotes http://example.com/f in the context of the base URI http://example.com/pathSeg/nsDoc.xml, the namespace recommendation associates the prefix a with ../foo, the un-expanded URI reference that occurs in the namespace declaration.

Q4:OK, then, what's the namespace name of the root element in thatDoc?

A4:../foo, per the namespaces spec as written.

But be careful with terminology. The 'namespace name' is ../foo, but the Namespaces Rec doesn't define a term 'Namespace URI'. According to section 4, URI References, in RFC 2396, "the URI" denoted by ../foo is http://example.org/foo -- and terms like "namespace URI", which allude to that mechanism, should be used with great caution.

Q5:In the infoset, what's the value of the in-scope-namespaces property of the root element of thatDoc?

A5: Unspecified; out of scope for this version of the infoset spec.

The infoset spec does not cover documents which are not well formed, or documents which are well-formed but don't conform to the Namespaces Rec. It also does not cover documents which are well formed and conform to the Namespaces Rec, but which use relative URI references in namespace declarations. Such documents are out of scope, and the infoset spec defines no infoset for them.

The XML Core WG is advised to revise the Infoset spec and specify its scope as described.

Q6:What does the DOM spec return for the namespaceURI attribute?

A6: Unspecified; out of scope for this version of DOM.

In the case of a namespace declaration with an absolute URI reference (i.e. a URI reference beginning with a scheme name and a colon), the DOM namespaceURI attribute returns that absolute URI reference.

But the namespaceURI attribute in the case of namespace declarations bearing relative URI references is unspecified.

The DOM WG is advised to revise the DOM2 spec and specify its scope as described.

Q7:what's the value of the XPath namespace-uri() function with <aDoc> as the current node?

A7: Unspecified.

The 16 November 1999 XPath specification progressed to Recommendation with the understanding that multiple interoperable implementations implemented it as specified, or would soon implement it as specified. As it turns out, we have no evidence that multiple interoperable implementations implement the namespace-uri() function as specified.

The XSL (and XLink? Query) WGs are advised to draft a revision of the XPath specification that does not specify the result of the namespace-uri() function in the case of a relative URI reference in a namespace declaration, and request Proposed Recommendation status for the resulting spec.

4.3 Ballot

On 3 July 2000, the chairs of the XML Plenary sent a ballot message to the plenary, asking each member organization represented in the plenary to indicate whether it found the proposal acceptable or unacceptable. Organizations were also allowed to abstain, or to instruct that their ballot be counted with the majority (above, this is termed a vote of concur):

Space for comments was also provided.

5. The data

Ballots were received from fifty-eight (58) organizations or individuals. Almost all of these have representatives in good standing serving on working groups in the XML activity, or the DOM WG, or the XSL WG, and individuals serving as invited experts on these working groups; three (not singled out in this tabulation) appear not to fit this description, but their votes do not affect the result.

6. Conclusions

It is the recommendation of the XML Plenary that the proposal described above be adopted, and that new specifications prepared by W3C Working Groups include statements similar to the following:

This specification does not define an information set [or whatever] for XML documents which use relative URIs in namespace declarations.

or

The scope of this specification includes all well-formed XML documents which use only absolute URI references in namespace declarations. Documents which use relative URI references are out of scope, and not addressed by this specification.

or words to similar effect.