Re: BUG #17088: FailedAssertion in prepagg.c

>>>>> "Tom" == Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> Andrew Gierth <andrew(at)tao11(dot)riddles(dot)org(dot)uk> writes:
>> A number of places in the planner have to explicitly avoid recursing
>> into GroupingFunc->args when walking trees specifically because they
>> are not evaluated. It looks to me like some places where that should
>> have been checked for were missed. Looking into it.

Tom> Hmm. Maybe it'd be better if the default behavior in
Tom> expression_tree_walker/mutator did not include recursing into the
Tom> args, then?

You'd think, but as I recall (I will re-check this to confirm) there
were more places where we _did_ need to recurse (especially during parse
analysis before we've matched up the sortgrouprefs), while most of the
places where recursion needed to be explicitly avoided already needed
special-case handling, so having the default the other way would likely
have required a special-case almost everywhere.

--
Andrew.