pá 20. 8. 2021 v 17:50 odesílatel Tom Lane <tgl@sss.pgh.pa.us> napsal:
In commit 2f48ede08 I copied some error-message wording that had existed in exec_run_select() since 2003. I'm now dissatified with that, after realizing that it can produce output like this:
ERROR: query "WITH a AS ( SELECT regexp_split_to_table(info_out, '\n') AS info FROM public.results WHERE public.results.jid = id ) SELECT * INTO tabular_info FROM a RETURN" is not a SELECT CONTEXT: PL/pgSQL function get_info(text) line 3 at RETURN QUERY
There are a couple of things wrong with this:
1. The complaint is factually inaccurate, since the query obviously *is* a SELECT. It's the INTO part that's the problem, but good luck guessing that from the error text. (See [1] for motivation.)
2. It's fairly unreadable when the query is a long multi-line one, as it does a great job of burying the lede. This also violates our message style guideline that says primary error messages should be one-liners.
The way to fix #1 is to provide a special case for SELECT INTO. In the attached I propose to fix #2 by moving the query text into an errcontext line, thus producing something like
ERROR: query is SELECT INTO, but it should be plain SELECT CONTEXT: query: WITH a AS ( SELECT regexp_split_to_table(info_out, '\n') AS info FROM public.results WHERE public.results.jid = id ) SELECT * INTO tabular_info FROM a RETURN PL/pgSQL function get_info(text) line 3 at RETURN QUERY
A case could also be made for just dropping the query text entirely, but I'm inclined to think that's not such a great idea. Certainly we ought to show the text in case of RETURN QUERY EXECUTE, where it won't be embedded in the function text.
Looking around, I noted that exec_eval_expr() also has the bad habit of quoting the expression text right in the primary message, so the attached fixes that too. That case is slightly less bad since expressions are more likely to be short, but they surely aren't all short.
Thoughts? Should I back-patch this into v14 where 2f48ede08 came in, or just do it in HEAD?
