Re: [PATCH proxmox 01/29] add new proxmox-match-expression crate

[Arthur Bied-Charreton <a.bied-charreton@proxmox.com>]

On Tue, Sep 22, 2026 at 10:56:59AM +0200, Lukas Wagner wrote:
> On Fri Sep 4, 2026 at 2:25 PM CEST, Robert Obkircher wrote:
> >
> > On 04.09.26 11:48, Lukas Wagner wrote:
> >>>> [..]
> >>>> +    pub fn evaluate(&self, data: &D) -> Result<EvaluatedExpressionWithResult<M>, E> {
> >>>> +        let evaluated_expression = match self {
> >>>> +            Expression::AllOf(expressions) => {
> >>>> +                if expressions.is_empty() {
> >>>> +                    // 'all-of' without any sub-expressions is *not* a match
> >>>> +                    EvaluatedExpressionWithResult {
> >>>> +                        expression: EvaluatedExpression::AllOf(Vec::new()),
> >>>> +                        matches: false,
> >>>> +                    }
> >>> this probaly does not matter too much as long as it's documented, but
> >>> intuitively (and based on implementations for all-expressions in 
> >>> other languages like rust and python) i would expect all([]) to evaluate to
> >>> true.
> >> Yeah, I see where you are coming from, but after some consideration I've
> >> decided that I'd like to keep it this way.
> >>
> >> For non-coders, all([]) being true is not very intuitive, and I'd prefer
> >> to just say "hey, all combinators eval to false if they have no
> >> children" in the docs.
> >
> > Even non-coders understand why all of my Ferraris are red :)
> >
> > Would it be possible to forbid the empty lists entirely? e.g. by
> > rewriting all([]) to true when someone saves an empty list.
> >
> 
> I'm not sure if I'm a fan of automatically rewriting rules, I think this
> is counter-intuitive for users.
> 
> But, giving this another thought:
> 
>   - since proxmox-match-expression is supposed to be generic, keep it 'mathmatically' correct,
>     so let all([]) eval to true
>   - disallow creating empty all-of/any-of/one-of rules in the UI and API
> 
> What do you think?
sounds good to me!
> 
> 
> 
>