Support volatile functions and scalar variables in ListingTable partition pruning

[gstvg]

Is your feature request related to a problem or challenge?

Currently ListingTable partition prunning doesn't support volatile functions and scalar variables, like now() or $var, which is checked at

datafusion/datafusion/catalog-listing/src/helpers.rs

Lines 51 to 118 in 4b8c1d9

	pub fn expr_applicable_for_cols(col_names: &[&str], expr: &Expr) -> bool {
	let mut is_applicable = true;
	expr.apply(|expr| match expr {
	Expr::Column(Column { name, .. }) => {
	is_applicable &= col_names.contains(&name.as_str());
	if is_applicable {
	Ok(TreeNodeRecursion::Jump)
	} else {
	Ok(TreeNodeRecursion::Stop)
	}
	}
	Expr::Literal(_, _)
	| Expr::Alias(_)
	| Expr::OuterReferenceColumn(_, _)
	| Expr::ScalarVariable(_, _)
	| Expr::Not(_)
	| Expr::IsNotNull(_)
	| Expr::IsNull(_)
	| Expr::IsTrue(_)
	| Expr::IsFalse(_)
	| Expr::IsUnknown(_)
	| Expr::IsNotTrue(_)
	| Expr::IsNotFalse(_)
	| Expr::IsNotUnknown(_)
	| Expr::Negative(_)
	| Expr::Cast(_)
	| Expr::TryCast(_)
	| Expr::BinaryExpr(_)
	| Expr::Between(_)
	| Expr::Like(_)
	| Expr::SimilarTo(_)
	| Expr::InList(_)
	| Expr::Exists(_)
	| Expr::InSubquery(_)
	| Expr::ScalarSubquery(_)
	| Expr::SetComparison(_)
	| Expr::GroupingSet(_)
	| Expr::Case(_) => Ok(TreeNodeRecursion::Continue),
	Expr::ScalarFunction(scalar_function) => {
	match scalar_function.func.signature().volatility {
	Volatility::Immutable => Ok(TreeNodeRecursion::Continue),
	// TODO: Stable functions could be `applicable`, but that would require access to the context
	Volatility::Stable | Volatility::Volatile => {
	is_applicable = false;
	Ok(TreeNodeRecursion::Stop)
	}
	}
	}
	// TODO other expressions are not handled yet:
	// - AGGREGATE and WINDOW should not end up in filter conditions, except maybe in some edge cases
	// - Can `Wildcard` be considered as a `Literal`?
	// - ScalarVariable could be `applicable`, but that would require access to the context
	// TODO: remove the next line after `Expr::Wildcard` is removed
	#[expect(deprecated)]
	Expr::AggregateFunction { .. }
	| Expr::WindowFunction { .. }
	| Expr::Wildcard { .. }
	| Expr::Unnest { .. }
	| Expr::Placeholder(_) => {
	is_applicable = false;
	Ok(TreeNodeRecursion::Stop)
	}
	})
	.unwrap();
	is_applicable
	}

Describe the solution you'd like

Volatile functions and scalar variables being supported in ListingTable partition pruning

Describe alternatives you've considered

No response

Additional context

Suggested by @comphead at #21679