Re: unrecognized node type while displaying a Path due to dangling pointer

On Tue, Jul 18, 2023 at 5:05 AM David Rowley <dgrowleyml(at)gmail(dot)com> wrote:
>
> On Mon, 17 Jul 2023 at 15:31, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > > I also didn't do anything about ExtensibleNode types. I assume just
> > > copying the ExtensibleNode isn't good enough. To flat copy the actual
> > > node I think would require adding a new function to
> > > ExtensibleNodeMethods.
> >
> > Yeah, the problem I've got with this approach is that flat-copying
> > FDW and Custom paths would require extending the respective APIs.
> > While that's a perfectly reasonable ask if we only need to do this
> > in HEAD, it would be a nonstarter for released branches. Is it
> > okay to only fix this issue in HEAD?
>
> CustomPaths, I didn't think about those. That certainly makes it more
> complex. I also now see the header comment for struct CustomPath
> mentioning that we don't copy Paths:

Somewhere upthread Tom suggested using a dummy projection path. Add a
projection path on top of input path and add the projection path to
output rel's list. That will work right?

There's some shallow copying code in reparameterize_path_by_childrel()
but that's very specific to the purpose there and doesn't consider
Custom or Foreign paths.

--
Best Wishes,
Ashutosh Bapat