Re: Latest patches break one of our unit-test, related to RLS

On Fri, 2025-09-12 at 21:53 -0400, Tom Lane wrote:
>
> Ah, got it.  But this logic definitely deserves more comments.
> What do you think of something like
>
>             if (pchar == ']' && charclass_start > 2)
>             {
>                 /* found the real end of a bracket pair */
>                 charclass_depth--;
>                 /* past start of outer brackets, so keep charclass_start > 2 */
>             }
>             else if (pchar == '[')
>             {
>                 /* start of a nested bracket pair */
>                 charclass_depth++;
>                 /* leading ^ or ] in this context is not special */
>                 charclass_start = 3;
>             }
>             else if (pchar == '^')
>             {
>                 /* okay to increment charclass_start even if already > 1 */
>                 charclass_start++;
>             }
>             else
>             {
>                 /* otherwise (including case of leading ']') */
>                 charclass_start = 3;    /* definitely past the start */
>             }
>
> > Perhaps s/charclass_depth/bracket_depth/ would be a good idea.
>
> Wouldn't object to that.  Maybe we can think of a better name for
> "charclass_start" too --- that sounds like a boolean condition.
> The best I'm coming up with right now is "charclass_count", but
> that's not that helpful.

I came up with the attached patch set.

0001 is the actual bug fix: in addition to my previous patch, I fixed two
more cases in which a closing bracket might not be recognized as ending
the character class (one is from your patch above).  I think that these
could not lead to bad query results, but I am not certain.

0002 is the cosmetic improvement: I renamed "charclass_depth" to "bracket_depth"
and "bracket_depth" to "bracket_pos", rewrote the "else if" cascade as you
suggested above and put some love into additional comments.

I used two separate patches for clarity and ease of review, but both
should get backpatched.

Yours,
Laurenz Albe