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

Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> writes:
> On Fri, 2025-09-12 at 20:12 -0400, Tom Lane wrote:
>> Should not we be setting charclass_start to 1 after incrementing
>> charclass_depth?

> What I call "charclass depth" is misleading, I am afraid.
> Really, it should be "bracket depth". Only the outermost pair of brackets
> starts an actual character class. Example:
> []abc[:digit:]]
> A caret or closing bracket right after the inner opening bracket wouldn't
> be a special character, and I think it would never be legal.

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.

regards, tom lane