Re: pg_parse_json() should not leak token copies on failure

Andrew Dunstan <andrew@dunslane.net>

From: Andrew Dunstan <andrew@dunslane.net>
To: Jacob Champion <jacob.champion@enterprisedb.com>, pgsql-hackers@postgresql.org
Cc: Michael Paquier <michael@paquier.xyz>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Date: 2024-10-02T17:45:05Z
Lists: pgsql-hackers
On 2024-10-01 Tu 3:04 PM, Jacob Champion wrote:
> (Tom, thank you for the fixup in 75240f65!)
>
> Off-list, Andrew suggested an alternative approach to the one I'd been
> taking: let the client choose whether it wants to take token ownership
> to begin with. v3 adds a new flag (and associated API) which will
> allow libpq to refuse ownership of those tokens. The lexer is then
> free to clean everything up during parse failures.
>
> Usually I'm not a fan of "do the right thing" flags, but in this case,
> libpq really is the outlier. And it's nice that existing clients
> (potentially including extensions) don't have to worry about an API
> change.


Yeah.

Generally looks good. Should we have a check in 
setJsonLexContextOwnsTokens() that we haven't started parsing yet, for 
the incremental case?



>
> At the moment, we have a test matrix consisting of "standard frontend"
> and "shlib frontend" tests for the incremental parser. I'm planning
> for the v4 patch to extend that with a "owned/not owned" dimension;
> any objections?
>

Sounds reasonable.


cheers


andrew

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




Commits

  1. jsonapi: add lexer option to keep token ownership