Re: Latest patches break one of our unit-test, related to RLS - Mailing list pgsql-general

On Fri, Sep 12, 2025 at 3:11 PM Dominique Devienne <ddevienne@gmail.com> wrote:
> On Fri, Sep 12, 2025 at 2:45 PM Laurenz Albe <laurenz.albe@cybertec.at> wrote:
> > You don't show us that data that match the pattern in 17.5, but
> > not in 17.6.  Unless you show us a counterexample, I'd say that
> > the behavior in 17.6 is correct.

I've reread https://www.postgresql.org/docs/current/functions-matching.html#FUNCTIONS-SIMILARTO-REGEXP
and especially:

> According to the SQL standard, omitting ESCAPE means there is no escape character (rather than defaulting to a
backslash),and a zero-length ESCAPE value is disallowed. PostgreSQL's behavior in this regard is therefore slightly
nonstandard.

and also

> Another nonstandard extension is that following the escape character with a letter or digit provides access to the
escapesequences defined for POSIX regular expressions; see Table 9.20, Table 9.21, and Table 9.22 below. 

Table 9.21. Regular Expression Class-Shorthand Escapes
\d matches any digit, like [[:digit:]]
\w matches any word character, like [[:word:]]

So I don't see how my `... where v similar to 'foo[\d\w]_%'` is incorrect.

So again, is this a bug / regression or not? Thanks, --DD