Feature Request: Populate targetlist for pg Plan*

[dentiny]

Why do you want this feature?
I'm working on a RETURNING clause for pg_mooncake, after some debugging I found is Plan* generated by pg_duckdb doesn't include targetlist data member, which leads to 0 natts thus no printed value.

After manually setting the targetlist to be

postgres_plan->planTree = duckdb_plan;
postgres_plan->planTree->targetlist = postgres_plan->planTree->targetlist;

it works in some cases.

Another observation, PlannedStmt* created by postgres does contain targetlist, not gets overwritten by duckdb plan. I expect the only difference between pg plan vs pg_duckdb plan to be execution plan, but not target list.

[JelteF]

This should be addressed by #468

[dentiny]

Thank you! I will close the feature request and wait for the PR to checkin :)