fix(qe): Change Array(None) to return Null value.

query-engine/connector-test-kit-rs/query-engine-tests/tests/queries/data_types/json.rs

@@ -380,7 +380,7 @@ mod json {
 
         insta::assert_snapshot!(
           run_query!(&runner, r#"{ findManyTestModel { child { json_list } } }"#),
-          @r###"{"data":{"findManyTestModel":[{"child":{"json_list":["1","2"]}},{"child":{"json_list":["{}"]}},{"child":{"json_list":["\"hello\"","\"world\""]}},{"child":{"json_list":[]}}]}}"###
+          @r###"{"data":{"findManyTestModel":[{"child":{"json_list":["1","2"]}},{"child":{"json_list":["{}"]}},{"child":{"json_list":["\"hello\"","\"world\""]}},{"child":{"json_list":null}}]}}"###
         );
 
         Ok(())

query-engine/connector-test-kit-rs/query-engine-tests/tests/queries/data_types/through_relation.rs

@@ -265,12 +265,12 @@ mod scalar_relations {
 
         insta::assert_snapshot!(
           run_query!(&runner, r#"{ findManyParent { id children { childId string int bInt float bytes bool dt empty unset } } }"#),
-          @r###"{"data":{"findManyParent":[{"id":1,"children":[{"childId":1,"string":["abc","def"],"int":[1,-1,1234567],"bInt":["1","-1","9223372036854775807","-9223372036854775807"],"float":[1.5,-1.5,1.234567],"bytes":["AQID","Qk9OSk9VUg=="],"bool":[false,true],"dt":["1900-10-10T01:10:10.001Z","1999-12-12T21:12:12.121Z"],"empty":[],"unset":[]}]}]}}"###
+          @r###"{"data":{"findManyParent":[{"id":1,"children":[{"childId":1,"string":["abc","def"],"int":[1,-1,1234567],"bInt":["1","-1","9223372036854775807","-9223372036854775807"],"float":[1.5,-1.5,1.234567],"bytes":["AQID","Qk9OSk9VUg=="],"bool":[false,true],"dt":["1900-10-10T01:10:10.001Z","1999-12-12T21:12:12.121Z"],"empty":[],"unset":null}]}]}}"###
         );
 
         insta::assert_snapshot!(
           run_query!(&runner, r#"{ findUniqueParent(where: { id: 1 }) { id children { childId string int bInt float bytes bool dt empty unset } } }"#),
-          @r###"{"data":{"findUniqueParent":{"id":1,"children":[{"childId":1,"string":["abc","def"],"int":[1,-1,1234567],"bInt":["1","-1","9223372036854775807","-9223372036854775807"],"float":[1.5,-1.5,1.234567],"bytes":["AQID","Qk9OSk9VUg=="],"bool":[false,true],"dt":["1900-10-10T01:10:10.001Z","1999-12-12T21:12:12.121Z"],"empty":[],"unset":[]}]}}}"###
+          @r###"{"data":{"findUniqueParent":{"id":1,"children":[{"childId":1,"string":["abc","def"],"int":[1,-1,1234567],"bInt":["1","-1","9223372036854775807","-9223372036854775807"],"float":[1.5,-1.5,1.234567],"bytes":["AQID","Qk9OSk9VUg=="],"bool":[false,true],"dt":["1900-10-10T01:10:10.001Z","1999-12-12T21:12:12.121Z"],"empty":[],"unset":null}]}}}"###
         );
 
         Ok(())

query-engine/connector-test-kit-rs/query-engine-tests/tests/writes/composites/list.rs

@@ -326,7 +326,7 @@ mod create {
           }
         }
         "#),
-          @r###"{"data":{"createOneTestModel":{"to_many_as":[],"to_one_b":null}}}"###
+          @r###"{"data":{"createOneTestModel":{"to_many_as":null,"to_one_b":null}}}"###
         );
 
         Ok(())

query-engine/connector-test-kit-rs/query-engine-tests/tests/writes/top_level_mutations/create_list.rs

@@ -27,7 +27,7 @@ mod create_list {
 
         insta::assert_snapshot!(
           run_query!(&runner, r#"mutation { createOneUser(data: { id: 1 }){ id, test }}"#),
-          @r###"{"data":{"createOneUser":{"id":1,"test":[]}}}"###
+          @r###"{"data":{"createOneUser":{"id":1,"test":null}}}"###
         );
 
         Ok(())

query-engine/connectors/mongodb-query-connector/src/value.rs

@@ -297,7 +297,7 @@ fn read_scalar_value(bson: Bson, meta: &ScalarOutputMeta) -> crate::Result<Prism
     let val = match (&meta.ident, bson) {
         // We expect a list to be returned.
         (type_identifier, bson) if meta.list => match bson {
-            Bson::Null => PrismaValue::List(Vec::new()),
+            Bson::Null => PrismaValue::Null,
 
             Bson::Array(list) => PrismaValue::List(
                 list.into_iter()
@@ -392,7 +392,7 @@ fn read_composite_value(bson: Bson, meta: &CompositeOutputMeta) -> crate::Result
     let val = if meta.list {
         match bson {
             // Coerce null to empty list (Prisma doesn't have nullable lists)
-            Bson::Null => PrismaValue::List(Vec::new()),
+            Bson::Null => PrismaValue::Null,
 
             Bson::Array(list) => PrismaValue::List(
                 list.into_iter()

query-engine/connectors/sql-query-connector/src/database/operations/read/coerce.rs

@@ -25,7 +25,7 @@ pub(crate) fn coerce_record_with_json_relation(
             IndexedSelection::Relation(rs) => {
                 match val {
                     PrismaValue::Null if rs.field.is_list() => {
-                        *val = PrismaValue::List(vec![]);
+                        *val = PrismaValue::Null;
                     }
                     PrismaValue::Null if rs.field.is_optional() => {
                         continue;
@@ -127,7 +127,7 @@ pub(crate) fn coerce_json_scalar_to_pv(value: serde_json::Value, sf: &ScalarFiel
 
     if sf.type_identifier().is_json() && sf.is_list() {
         return match value {
-            serde_json::Value::Null => Ok(PrismaValue::List(vec![])),
+            serde_json::Value::Null => Ok(PrismaValue::Null),
             serde_json::Value::Array(values) => Ok(PrismaValue::List(
                 values
                     .iter()
@@ -139,13 +139,7 @@ pub(crate) fn coerce_json_scalar_to_pv(value: serde_json::Value, sf: &ScalarFiel
     }
 
     match value {
-        serde_json::Value::Null => {
-            if sf.is_list() {
-                Ok(PrismaValue::List(vec![]))
-            } else {
-                Ok(PrismaValue::Null)
-            }
-        }
+        serde_json::Value::Null => Ok(PrismaValue::Null),
         serde_json::Value::Bool(b) => Ok(PrismaValue::Boolean(b)),
         serde_json::Value::Number(n) => match sf.type_identifier() {
             TypeIdentifier::Int => Ok(PrismaValue::Int(n.as_i64().ok_or_else(|| {

query-engine/connectors/sql-query-connector/src/row.rs

@@ -95,8 +95,8 @@ impl ToSqlRow for ResultRow {
         for (i, p_value) in self.into_iter().enumerate().take(row_width) {
             let pv = match (meta[i].identifier(), meta[i].arity()) {
                 (type_identifier, FieldArity::List) => match p_value.typed {
-                    value if value.is_null() => Ok(PrismaValue::List(Vec::new())),
-                    ValueType::Array(None) => Ok(PrismaValue::List(Vec::new())),
+                    value if value.is_null() => Ok(PrismaValue::Null),
+                    ValueType::Array(None) => Ok(PrismaValue::Null),
                     ValueType::Array(Some(l)) => l
                         .into_iter()
                         .map(|val| row_value_to_prisma_value(val, meta[i]))