Re: [PATCH] Fix escaping for '\' and '"' in pageinspect for gist

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

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Roman Khapov <rkhapov@yandex-team.ru>
Cc: pgsql-hackers@lists.postgresql.org, michael@paquier.xyz
Date: 2025-12-29T18:37:14Z
Lists: pgsql-hackers
Roman Khapov <rkhapov@yandex-team.ru> writes:
> I noticed, that there is bug in escaping values that contains '\' or '"' in text representation
> inside pageinspect for gist: the string 'foo"bar' are printed like "foo""bar" and not "foo\"bar".

I do not think this is a bug.  The comment at line 295 says
"Most of this is copied from record_out().", and this logic
matches what record_out() does, and the output is legal
according to the manual's specifications [1]:

    To put a double quote or backslash in a quoted composite field
    value, precede it with a backslash. (Also, a pair of double quotes
    within a double-quoted field value is taken to represent a double
    quote character, analogously to the rules for single quotes in SQL
    literal strings.)

Now, your alternative coding would also produce legal output, but
I do not think unnecessary change here is a good thing.

			regards, tom lane

[1] https://www.postgresql.org/docs/devel/rowtypes.html#ROWTYPES-IO-SYNTAX