Re: Don't pass NULL pointer to strcmp().
| От | Xing Guo |
|---|---|
| Тема | Re: Don't pass NULL pointer to strcmp(). |
| Дата | |
| Msg-id | CACpMh+BoYMLj-ZmzCY8LChQWjyxgxxuGLf+Mmoz8NAg2o_3v7w@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Don't pass NULL pointer to strcmp(). (Tom Lane <tgl@sss.pgh.pa.us>) |
| Ответы |
Re: Don't pass NULL pointer to strcmp().
|
| Список | pgsql-hackers |
Hi Tom,
There're extensions that set their boot_val to NULL. E.g., postgres_fdw (https://github.com/postgres/postgres/blob/4210b55f598534db9d52c4535b7dcc777dda75a6/contrib/postgres_fdw/option.c#L582), plperl (https://github.com/postgres/postgres/blob/4210b55f598534db9d52c4535b7dcc777dda75a6/src/pl/plperl/plperl.c#L422C13-L422C13, https://github.com/postgres/postgres/blob/4210b55f598534db9d52c4535b7dcc777dda75a6/src/pl/plperl/plperl.c#L444C12-L444C12, https://github.com/postgres/postgres/blob/4210b55f598534db9d52c4535b7dcc777dda75a6/src/pl/plperl/plperl.c#L452C6-L452C6) (Can we treat plperl as an extension?), pltcl (https://github.com/postgres/postgres/blob/4210b55f598534db9d52c4535b7dcc777dda75a6/src/pl/tcl/pltcl.c#L465C14-L465C14, https://github.com/postgres/postgres/blob/4210b55f598534db9d52c4535b7dcc777dda75a6/src/pl/tcl/pltcl.c#L472C12-L472C12).
TBH, I don't know if NULL is a valid boot_val for string variables, I just came across some extensions that use NULL as their boot_val. If the boot_val can't be NULL in extensions, we should probably add some assertions or comments about it?
Best Regards,
Xing
On Wed, Nov 1, 2023 at 11:30 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
Xing Guo <higuoxing@gmail.com> writes:
> Thanks for your comments. I have updated the patch accordingly.
I'm leery of accepting this patch, as I see no reason that we
should consider it valid for an extension to have a string GUC
with a boot_val of NULL.
I realize that we have a few core GUCs that are like that, but
I'm pretty sure that every one of them has special-case code
that initializes the GUC to something non-null a bit later on
in startup. I don't think there are any cases where a string
GUC's persistent value will be null, and I don't like the
idea of considering that to be an allowed case. It would
open the door to more crash situations, and it brings up the
old question of how could a user tell NULL from empty string
(via SHOW or current_setting() or whatever). Besides, what's
the benefit really?
regards, tom lane
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