Preserve UDAF distincit flag in serde (#259)

Author: joroKr21

datafusion/proto/proto/datafusion.proto

@@ -522,6 +522,7 @@ message AggregateUDFExprNode {
   repeated LogicalExprNode args = 2;
   LogicalExprNode filter = 3;
   repeated LogicalExprNode order_by = 4;
+  bool distinct = 5;
   optional bytes fun_definition = 6;
 }
 

datafusion/proto/src/generated/pbjson.rs

@@ -658,7 +658,7 @@ pub fn parse_expr(
             Ok(Expr::AggregateFunction(expr::AggregateFunction::new_udf(
                 agg_fn,
                 parse_exprs(&pb.args, registry, codec)?,
-                false,
+                pb.distinct,
                 parse_optional_expr(pb.filter.as_deref(), registry, codec)?.map(Box::new),
                 parse_vec_expr(&pb.order_by, registry, codec)?,
                 None,

datafusion/proto/src/generated/prost.rs

@@ -502,6 +502,7 @@ pub fn serialize_expr(
                                 Some(e) => serialize_exprs(e, codec)?,
                                 None => vec![],
                             },
+                            distinct: *distinct,
                             fun_definition: (!buf.is_empty()).then_some(buf),
                         },
                     ))),