Re: [xml] xmlRemoveID bug and a patch

[Daniel Veillard <veillard redhat com>]

On Sun, Aug 31, 2003 at 01:45:05AM +0100, bill hobbiton cjb net wrote:
> I appreciate that the 'IDness' is only defined by the presence of the
> attribute and the attribute's declaration as an ID type in the DTD.  
> However, the problem is that when I rename an attribute with xmlSetProp
> that is an ID, the value is changed in the xml tree, but the respective
> document's ID hash table is not updated to the correct value. As a result

  Right, that is a bug, point taken ! This need fixing...

> of this, future xmlGetID lookups may give false positives for attributes
> that were removed. So, it seems that I am supposed to remove the ID
> explicitely from the documents IDs hash table with xmlRemoveID, which is
> documented as removing "the given attribute from the ID table maintained
> internally." In the function's present form, this appears to always fail
> due to a miscast pointer:
>
>     xmlAttrPtr cur;
> .
> .
> .
>     cur = xmlHashLookup(table, ID);
>     if (cur != attr) {
>         xmlFree(ID);
>         return(-1);
>     }
>
>
> The 'table' pointer, which refers to a document's 'ids' table has inserted
> into it xmlIDPtrs by the xmlAddID function. Here, they are being cast into 
> a xmlAttrPtr and compared with the xmlAttrPtr parameter 'attr'.

  Hum, right too, the ID table used to point directly to an xmlAttrPtr
and this is not the case anymore, bug #2

> I understand that an attribute being an ID is dependent on the DTD. What I
> am trying to get at is that xmlUnsetProp and xmlFreeProp will _check_ the
> property to see if it as an ID with xmlIsID and then (attempt to) remove
> the internal hash table reference with xmlRemoveID, whereas xmlSetProp
> will not perform any such check. To me, it would seem logical to make this

   This is a bug in xmlSetProp, an that need to be fixed.

> Please find attached a sample program and xml file that should demonstrate
> the xmlRemoveID IDs hash table problem. I have hopefully included enough
> commentary in the source code for you to be able to comprehend its
> behavoiral objectives. If I have misinterpreted the desired use of any of
> the function calls, then please accept my apologies and my polite request
> that you point out where I have gone wrong. If you need any further 
> clarifications of the example, please don't hesitate to contact me.

   No that's fine, thanks for the detailed program and explanations,
I will try to get those bugs fixed.

  thanks,

Daniel

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-- 
Daniel Veillard      | Red Hat Network https://rhn.redhat.com/
veillard redhat com  | libxml GNOME XML XSLT toolkit  http://xmlsoft.org/
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