Re: BUG #5534: IS DOCUMENT predicate errors instead of returning false

Quoting Mike Fowler <mike(at)mlfowler(dot)com>:

>
> The following bug has been logged online:
>
> Bug reference: 5534
> Logged by: Mike Fowler
> Email address: mike(at)mlfowler(dot)com
> PostgreSQL version: 9.0beta2
> Operating system: Linux 2.6.31-14-generic #48-Ubuntu SMP
> Description: IS DOCUMENT predicate errors instead of returning false
> Details:
>
> IS DOCUMENT should return false for a non-well formed document, and indeed
> is coded to do such. However, the conversion to the xml type which happens
> before the underlying xml_is_document function is even called fails and
> exceptions out. I've mentioned this on -hackers with message ID
> 20100701172553(dot)w5vdy1xbocos8g40(at)www(dot)mlfowler(dot)com
>
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The attached patch is a very small patch that changes parse_expr.c to
not convert everything to xml. This now means that when passed
malformed XML it will return false instead of throwing an exception.
In my mind this acceptable as I don't see anywhere in the standard
that mandates that:

xmlval IS NOT DOCUMENT == xmlval IS CONTENT

Regards,

--
Mike Fowler
Registered Linux user: 379787