Re: JSON/SQL: jsonpath: incomprehensible error message

On 2022-06-26 Su 11:44, Erik Rijkers wrote:
> JSON/SQL jsonpath
>
> For example, a jsonpath string with deliberate typo 'like_regexp'
> (instead of 'like_regex'):
>
> select js
> from (values (jsonb '{}')) as f(js)
> where js @? '$ ? (@ like_regexp "^xxx")';
>
> ERROR:  syntax error, unexpected IDENT_P at or near " " of jsonpath input
> LINE 1: ...s from (values (jsonb '{}')) as f(js) where js @? '$ ? (@
> li...
>                                                              ^
>
> Both  'IDENT_P'  and  'at or near " "'  seem pretty useless.
>
> Perhaps some improvement can be thought of?
>
> Similar messages in release 14 seem to use 'invalid token', which is
> better:
>
> select js
> from (values (jsonb '{"a":"b"}')) as f(js)
> where js @? '$ ? (@.a .= "b")';
> ERROR:  syntax error, unexpected invalid token at or near "=" of
> jsonpath input
>
>

Yeah :-(

This apparently goes back to the original jsonpath commit 72b6460336e.
There are similar error messages in the back branch regression tests:

andrew(at)ub20:pgl $ grep -r IDENT_P pg_*/src/test/regress/expected/
pg_12/src/test/regress/expected/jsonpath.out:ERROR:  syntax error, unexpected IDENT_P at end of jsonpath input
pg_13/src/test/regress/expected/jsonpath.out:ERROR:  syntax error, unexpected IDENT_P at end of jsonpath input
pg_14/src/test/regress/expected/jsonpath.out:ERROR:  syntax error, unexpected IDENT_P at end of jsonpath input

For some reason the parser contains a '%error-verbose' directive, unlike
all our other bison parsers. Removing that fixes it, as in this patch.
I'm a bit inclined to say we should backpatch the removal of the
directive, but I guess a lack of complaints suggests it's not a huge issue.

cheers

andrew

--
Andrew Dunstan
EDB: https://www.enterprisedb.com