Horton
Menu

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

Tom Lane <tgl@sss.pgh.pa.us>

View thread
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Xing Guo <higuoxing@gmail.com>
Cc: Aleksander Alekseev <aleksander@timescale.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Junwang Zhao <zhjwpku@gmail.com>
Date: 2023-11-02T01:57:18Z
Lists: pgsql-hackers

Attachments

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.

It's possible that some of these are unreachable --- for example,
given that a NULL could only be the default value, I'm not sure that
the fix in write_one_nondefault_variable is a live bug.  But we ought
to code all this stuff defensively, and most of it already was
NULL-safe.

			regards, tom lane

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"