Re: pgsql: Add GET DIAGNOSTICS ... PG_CONTEXT in PL/PgSQL

Stephen Frost <sfrost(at)snowman(dot)net> writes:
> * Tom Lane (tgl(at)sss(dot)pgh(dot)pa(dot)us) wrote:
>> If you want I'll draft something up.

> I'll take care of it, thanks for the idea!

OK. One possibly non-obvious point is that I think the field should be
defined as "context containing associated non-constant strings"; this
would mean in particular that CopyErrorData would need to change it
to CurrentMemoryContext in the copied struct, and then ReThrowError
would change it back when restoring the data onto the error stack.
This detail is probably a no-op in current usages, but in the future it
might allow modification of a copied ErrorData while it's outside
ErrorContext, if anyone should want to do that.

Also I'd advise declaring the field as "struct MemoryContextData *"
to avoid having to include palloc.h into elog.h.

regards, tom lane