Re: Missing can't-assign-to-constant checks in plpgsql

čt 28. 4. 2022 v 23:52 odesílatel Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> napsal:

> I happened to notice that there are a couple of places in plpgsql
> that will let you assign a new value to a variable that's marked
> CONSTANT:
>
> * We don't complain if an output parameter in a CALL statement
> is constant.
>
> * We don't complain if a refcursor variable is constant, even
> though OPEN may assign a new value to it.
>
> The attached quick-hack patch closes both of these oversights.
>
> Perhaps the OPEN change is a little too aggressive, since if
> you give the refcursor variable some non-null initial value,
> OPEN won't change it; in that usage a CONSTANT marking could
> be allowed. But I really seriously doubt that anybody out
> there is marking such variables as constants, so I thought
> throwing the error at compile time was better than postponing
> it to runtime so we could handle that.
>
> Regardless of which way we handle that point, I'm inclined to
> change this only in HEAD. Probably people wouldn't thank us
> for making the back branches more strict.
>

+1

I can implement these checks in plpgsql_check. So possible issues can be
detected and fixed on older versions by using plpgsql_check.

Regards

Pavel

> regards, tom lane
>
> PS: I didn't do it here, but I'm kind of tempted to pull out
> all the cursor-related tests in plpgsql.sql and move them to
> a new test file under src/pl/plpgsql/src/sql/. They look
> pretty self-contained, and I doubt they're worth keeping in
> the core tests.
>
>