Horton

Re: safer node casting

Peter Eisentraut <peter.eisentraut@2ndquadrant.com>

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From: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@anarazel.de>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2017-02-24T16:17:26Z
Lists: pgsql-hackers 
On 2/24/17 10:54, Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
>> Those aren't actually equivalent, because of the !nodeptr. IsA() crashes
>> for NULL pointers, but the new code won't. Which means 9ba8a9ce4548b et
>> al actually weakened some asserts.
> 
>> Should we perhaps have one NULL accepting version (castNodeNull?) and
>> one that separately asserts that ptr != NULL?
> 
> -1 ... if you're going to use something in a way that requires it not to
>  be null, your code will crash quite efficiently on a null, with or
>  without an assert.  I don't think we need the extra cogitive burden of
>  two distinct macros for this.

I think we should just add some Assert(thepointer) where necessary.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. Suppress unused-variable warning.

  2. Make more use of castNode()

  3. Add castNode(type, ptr) for safe casting between NodeTag based types.

  4. Use the new castNode() macro in a number of places.