Comparison predicates and quantified comparison predicates should hint array type to org.jooq.impl.Array for empty expression array casts

[lukaseder]

Due to erasure, we can't know what the type of a generic expression array is:

SQLDialect dialect = SQLDialect.POSTGRES;

Field<String>[] fields = new Field[0];
println(DSL.using(dialect).render(array(fields)));
println(DSL.using(dialect).render(any(array(fields))));
println(DSL.using(dialect).render(val("x").eq(any(array(fields)))));
println(DSL.using(dialect).render(array("x").eq(array(fields))));

This currently prints:

cast(array[] as int[])
any (cast(array[] as int[]))
false
array[?] = cast(array[] as int[])

The int[] casts are wrong, they're just a historic default from org.jooq.impl.Array (probably text[] would have been a better default, as PostgreSQL tends to use text as a default data type, occasionally).

The third result is due to a regression in our implementation of quantified comparison predicates, see:

• Regression in PostgreSQL query using 'x' = ANY (ARRAY [(SELECT ARRAY ['x'])]) style quantified comparison predicate on multi dimensional arrays #15980

After fixing #15980, we'll get:

cast(array[] as int[])
any (cast(array[] as int[]))
? = any (cast(array[] as int[]))
array[?] = cast(array[] as int[])

But in all cases, we know the comparison expression's left hand side's type, so we could hint it to the right hand side, as we often do.

[lukaseder]

Fixed in versions:

• 3.20.0
• 3.19.2 (Comparison predicates and quantified comparison predicates should hint array type to org.jooq.impl.Array for empty expression array casts - Merge [#15982] #15983)
• 3.18.9 (Comparison predicates and quantified comparison predicates should hint array type to org.jooq.impl.Array for empty expression array casts - Merge [#15982] #15984)

The fix will be included with #15980