sql: move NullableArgs function property to overload level

Currently we only have builtins, and that all overloads of a
same function name share function properties. However, we're
going to support user defined functions whose properties can
vary as how users define them. So we need to move any property
that's relevant to UDF to overload level. Currently, `NullableArgs`
is the only one matters.

Release note: None.

pkg/sql/colexec/builtin_funcs.go

@@ -70,7 +70,7 @@ func (b *defaultBuiltinFuncOperator) Next() coldata.Batch {
 					err error
 				)
 				// Some functions cannot handle null arguments.
-				if hasNulls && !b.funcExpr.CanHandleNulls() {
+				if hasNulls && !b.funcExpr.ResolvedOverload().NullableArgs {
 					res = tree.DNull
 				} else {
 					res, err = b.funcExpr.ResolvedOverload().

pkg/sql/execinfra/execagg/base.go

@@ -38,7 +38,7 @@ func GetAggregateInfo(
 		return builtins.NewAnyNotNullAggregate, inputTypes[0], nil
 	}
 
-	props, builtins := builtins.GetBuiltinProperties(strings.ToLower(fn.String()))
+	_, builtins := builtins.GetBuiltinProperties(strings.ToLower(fn.String()))
 	for _, b := range builtins {
 		typs := b.Types.Types()
 		if len(typs) != len(inputTypes) {
@@ -47,7 +47,7 @@ func GetAggregateInfo(
 		match := true
 		for i, t := range typs {
 			if !inputTypes[i].Equivalent(t) {
-				if props.NullableArgs && inputTypes[i].IsAmbiguous() {
+				if b.NullableArgs && inputTypes[i].IsAmbiguous() {
 					continue
 				}
 				match = false
@@ -131,7 +131,7 @@ func GetWindowFunctionInfo(
 			"function is neither an aggregate nor a window function",
 		)
 	}
-	props, builtins := builtins.GetBuiltinProperties(strings.ToLower(funcStr))
+	_, builtins := builtins.GetBuiltinProperties(strings.ToLower(funcStr))
 	for _, b := range builtins {
 		typs := b.Types.Types()
 		if len(typs) != len(inputTypes) {
@@ -140,7 +140,7 @@ func GetWindowFunctionInfo(
 		match := true
 		for i, t := range typs {
 			if !inputTypes[i].Equivalent(t) {
-				if props.NullableArgs && inputTypes[i].IsAmbiguous() {
+				if b.NullableArgs && inputTypes[i].IsAmbiguous() {
 					continue
 				}
 				match = false

pkg/sql/opt/memo/constraint_builder.go

@@ -434,7 +434,7 @@ func (cb *constraintsBuilder) buildConstraintForTupleInequality(
 func (cb *constraintsBuilder) buildFunctionConstraints(
 	f *FunctionExpr,
 ) (_ *constraint.Set, tight bool) {
-	if f.Properties.NullableArgs {
+	if f.FunctionPrivate.Overload.NullableArgs {
 		return unconstrained, false
 	}
 

pkg/sql/opt/norm/fold_constants_funcs.go

@@ -562,7 +562,7 @@ func (c *CustomFuncs) FoldColumnAccess(
 //
 // See FoldFunctionWithNullArg for more details.
 func (c *CustomFuncs) CanFoldFunctionWithNullArg(private *memo.FunctionPrivate) bool {
-	return !private.Properties.NullableArgs &&
+	return !private.Overload.NullableArgs &&
 		private.Properties.Class == tree.NormalClass
 }
 

pkg/sql/opt/optbuilder/sql_fn.go

@@ -63,7 +63,7 @@ func (b *Builder) buildSQLFn(
 			))
 		}
 		exprs[i] = memo.ExtractConstDatum(info.args[i])
-		if exprs[i] == tree.DNull && !info.def.Properties.NullableArgs {
+		if exprs[i] == tree.DNull && !info.def.Overload.NullableArgs {
 			return b.factory.ConstructNull(info.ResolvedType())
 		}
 	}