when i use isIn(emptyList) where condition, it would not render to sql

[clcy1243]

code example

select(s -> s.where(id, isIn(new ArrayList<>()));

will render like this

select * from table

it should be like

select * from table where id in ()

and mysql where throw exception when execute this sql, it's what my want,
so i think there is a bug,
i found this code at org.mybatis.dynamic.sql.where.render.WhereConditionVisitor<T>

    public Optional<FragmentAndParameters> visit(AbstractListValueCondition<T> condition) {
        FragmentCollector fc = (FragmentCollector)condition.mapValues(this::toFragmentAndParameters).collect(FragmentCollector.collect());
        return fc.isEmpty() ? Optional.empty() : FragmentAndParameters.withFragment(condition.renderCondition(this.columnName(), fc.fragments())).withParameters(fc.parameters()).buildOptional();
    }

if list value condition accept an empty list, fc.isEmpty() will be true, this condition where be deleted

could anyone fix this?

[jeffgbutler]

I don't agree this is a bug - I think it is actually a good thing that the library won't generate invalid SQL. I think it would be best to check to see if the list is empty before trying to execute the statement. If it is a possibility in your app that the list could be empty, then do you really want to rely on causing a database exception as a kind of validation?

Honestly it wouldn't be too hard to provide an option to render these conditions even when they are empty. But I'm not convinced that is a good idea.

Thoughts???

[clcy1243]

I don't agree this is a bug - I think it is actually a good thing that the library won't generate invalid SQL. I think it would be best to check to see if the list is empty before trying to execute the statement. If it is a possibility in your app that the list could be empty, then do you really want to rely on causing a database exception as a kind of validation?

Honestly it wouldn't be too hard to provide an option to render these conditions even when they are empty. But I'm not convinced that is a good idea.

Thoughts???

if i want ignore invalid condition, i will use IsInWhenPresent but not IsIn, i think there is IsInWhenPresent method, so IsIn mean it will render this condition even if it is invalid

[clcy1243]

there is two method do same thing with diff name, may be there should has one method named IsInRequired?

[jeffgbutler]

IsInWhenPresent filters null values out of the list. It will still not render if the list ends up being empty.

[clcy1243]

with 1.3.7 generator, i use Example, when i use andIdIn(emptyList), will throw exception,
so i should change my code to use mybatis-dynamic-sql,
when i use isIn , i should valid my param

[clcy1243]

there is a problem, when i build sql with not valid param, it where change more data than what i want it modify,
and i should check param each step now

[jeffgbutler]

I get it. I really do think you should be validating, but I understand it could be a change to how you're working now and not doing it would cause undesirable side effects.

I've been experimenting a bit. I can enable you to write a condition that will force the exception with a very simple code change. I'll push something to address this shortly.

[clcy1243]

Thanks for understanding

[clcy1243]

Here is 4:00am, I will try it when I waked up.