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Re: Don't pass NULL pointer to strcmp().

Nathan Bossart <nathandbossart@gmail.com>

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From: Nathan Bossart <nathandbossart@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Xing Guo <higuoxing@gmail.com>, Aleksander Alekseev <aleksander@timescale.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Junwang Zhao <zhjwpku@gmail.com>
Date: 2023-11-02T02:32:55Z
Lists: pgsql-hackers 
On Wed, Nov 01, 2023 at 09:57:18PM -0400, Tom Lane wrote:
> I wrote:
>> Hmm ... if we're doing it ourselves, I suppose we've got to consider
>> it supported :-(.  But I'm still wondering how many seldom-used
>> code paths didn't get the message.  An example here is that this
>> could lead to GetConfigOptionResetString returning NULL, which
>> I think is outside its admittedly-vague API spec.
> 
> After digging around for a bit, I think part of the problem is a lack
> of a clearly defined spec for what should happen with NULL string GUCs.
> In the attached v3, I attempted to remedy that by adding a comment in
> guc_tables.h (which is maybe not the best place but I didn't see a
> better one).  That led me to a couple more changes beyond what you had.

What if we disallowed NULL string GUCs in v17?  That'd simplify the spec
and future-proof against similar bugs, but it might also break a fair
number of extensions.  If there aren't any other reasons to continue
supporting it, maybe it's the right long-term approach, though.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Make GetConfigOption/GetConfigOptionResetString return "" for NULL.

  2. Be more wary about NULL values for GUC string variables.

  3. doc: Replace reference to ERRCODE_RAISE_EXCEPTION by "raise_exception"