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<bugzilla version="5.0.4"
          urlbase="https://www.w3.org/Bugs/Public/"
          
          maintainer="sysbot+bugzilla@w3.org"
>

    <bug>
          <bug_id>3235</bug_id>
          
          <creation_ts>2006-05-09 10:09:28 +0000</creation_ts>
          <short_desc>Acyclicity of union type definitions</short_desc>
          <delta_ts>2008-05-31 07:48:49 +0000</delta_ts>
          <reporter_accessible>1</reporter_accessible>
          <cclist_accessible>1</cclist_accessible>
          <classification_id>1</classification_id>
          <classification>Unclassified</classification>
          <product>XML Schema</product>
          <component>Datatypes: XSD Part 2</component>
          <version>1.1 only</version>
          <rep_platform>PC</rep_platform>
          <op_sys>Windows XP</op_sys>
          <bug_status>CLOSED</bug_status>
          <resolution>FIXED</resolution>
          
          
          <bug_file_loc></bug_file_loc>
          <status_whiteboard>cluster: cycles</status_whiteboard>
          <keywords>resolved</keywords>
          <priority>P1</priority>
          <bug_severity>normal</bug_severity>
          <target_milestone>---</target_milestone>
          
          
          <everconfirmed>1</everconfirmed>
          <reporter name="Michael Kay">mike</reporter>
          <assigned_to name="C. M. Sperberg-McQueen">cmsmcq</assigned_to>
          
          
          <qa_contact name="XML Schema comments list">www-xml-schema-comments</qa_contact>

      

      

      

          <comment_sort_order>oldest_to_newest</comment_sort_order>  
          <long_desc isprivate="0" >
    <commentid>9647</commentid>
    <comment_count>0</comment_count>
    <who name="Michael Kay">mike</who>
    <bug_when>2006-05-09 10:09:28 +0000</bug_when>
    <thetext>QT approved comment:

In 2.6.1.3, the definitions of &quot;transitive membership&quot; et seq make the
unstated assumption that the relation between a union type and its member
types is acyclic.</thetext>
  </long_desc><long_desc isprivate="0" >
    <commentid>16683</commentid>
    <comment_count>1</comment_count>
    <who name="C. M. Sperberg-McQueen">cmsmcq</who>
    <bug_when>2007-09-19 03:53:45 +0000</bug_when>
    <thetext>Thank you; yes, the discussion does assume that the relation between a
union and its member types is acyclic (or, equivalently, that no union
is a member of its own transitive membership).

This is explicitly required by the Schema Representation Constraint: 
Simple Type Definition Representation OK in section 3.16.3 of part 1 
(Structures) of XSDL 1.1.  

It&apos;s not clear to me how Structures section 3.16 and Datatypes
section 4.1 have gotten out of synch again, after a long and trying
effort to reconcile them.  But it seems clear that they need to
be reconciled once more.  </thetext>
  </long_desc><long_desc isprivate="0" >
    <commentid>17455</commentid>
    <comment_count>2</comment_count>
    <who name="C. M. Sperberg-McQueen">cmsmcq</who>
    <bug_when>2007-10-26 22:21:05 +0000</bug_when>
    <thetext>The WG discussed this issue (and in particular the alignment of Structures and
Datatypes) at its call of 26 October 2007.  We concluded that the goal of the
earlier alignment work was not to make the relevant sections of Structures and
Datatypes effectively identical, but only to ensure that material appearing 
in both specs should be the same in both.  This includes the tableaux and some
textual descriptions.  The goal had not been (we believe) to require that every
constraint in these sections of Structures also appear in Datatypes, and vice
versa -- only the ones that &apos;belong&apos; in the particular spec.  (The notion of
belonging is of course slightly fuzzy.)

The WG instructed the editors to compare the relevant parts of the two specs
and make recommendations for duplicating or moving text as appropriate.

With regard to the particular issue raised here, the WG instructed the editors
to prepare a wording proposal to capture, in Datatypes, the constraint that
no union be a member of its own transitive membership.  So the status of 
this bug is changed from needsAgreement to needsDrafting.</thetext>
  </long_desc><long_desc isprivate="0" >
    <commentid>20330</commentid>
    <comment_count>3</comment_count>
    <who name="C. M. Sperberg-McQueen">cmsmcq</who>
    <bug_when>2008-05-30 05:30:44 +0000</bug_when>
    <thetext>A wording proposal intended to resolve this issue is at
http://www.w3.org/XML/Group/2004/06/xmlschema-2/datatypes.b3235.html
(member-only link).</thetext>
  </long_desc><long_desc isprivate="0" >
    <commentid>20343</commentid>
    <comment_count>4</comment_count>
    <who name="C. M. Sperberg-McQueen">cmsmcq</who>
    <bug_when>2008-05-31 02:49:16 +0000</bug_when>
    <thetext>The wording proposal mentioned in comment #3 was adopted by the WG
at today&apos;s call; with that, I am marking the issue resolved.

Michael, as the originator of the issue and as our contact wtih the
QT working groups, would you please report on the resolution to QT
and indicate by closing the issue that they are happy with the resolution
(well, satisfied if not happy), or by reopening it that they are not
satisfied?  If we don&apos;t hear from you within the next two weeks, we
expect to assume that silence implies consent.</thetext>
  </long_desc>
      
      

    </bug>

</bugzilla>