Feedback-ID: ia2694551:Fastmail
Date: Thu, 29 Feb 2024 11:35:21 +0100
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Jelte Fennema-Nio <me@jeltef.nl>
Cc: Daniel Gustafsson <daniel@yesql.se>, 
	PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Peter Eisentraut <peter@eisentraut.org>
Subject: Re: Support a wildcard in backtrace_functions
Message-ID: <202402291035.op26n4voqmba@alvherre.pgsql>
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On 2024-Feb-28, Jelte Fennema-Nio wrote:

> diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
> index 699d9d0a241..553e4785520 100644
> --- a/src/backend/utils/error/elog.c
> +++ b/src/backend/utils/error/elog.c
> @@ -843,6 +843,8 @@ matches_backtrace_functions(const char *funcname)
>  		if (*p == '\0')			/* end of backtrace_function_list */
>  			break;
>  
> +		if (strcmp("*", p) == 0)
> +			return true;
>  		if (strcmp(funcname, p) == 0)
>  			return true;
>  		p += strlen(p) + 1;

Hmm, so if I write "foo,*" this will work but check all function names
first and on the second entry.  But if I write "foo*" the GUC value will
be accepted but match nothing (as will "*foo" or "foo*bar").  I don't
like either of these behaviors.  I think we should tighten this up: an
asterisk should be allowed only if it appears alone in the string
(short-circuiting check_backtrace_functions before strspn); and let's
leave the strspn() call alone.

-- 
Álvaro Herrera               48°01'N 7°57'E  —  https://www.EnterpriseDB.com/
Bob [Floyd] used to say that he was planning to get a Ph.D. by the "green
stamp method," namely by saving envelopes addressed to him as 'Dr. Floyd'.
After collecting 500 such letters, he mused, a university somewhere in
Arizona would probably grant him a degree.              (Don Knuth)