Formatting problem fix of scalar fields selected several times (#1585)

Author: eole1712

NEXT_CHANGELOG.md

@@ -172,6 +172,12 @@ Move the location of the `text` field when exposing the query plan and fill it w
 
 By [@bnjjj](https://github.com/bnjjj) in https://github.com/apollographql/router/pull/1557
 
+### Formatting problem fix of scalar fields selected several times ([PR #1583](https://github.com/apollographql/router/issues/1583))
+
+Fixed a bug where querying scalar fields several times would put `null`s instead of expected values.
+
+By [@eole1712](https://github.com/eole1712) in https://github.com/apollographql/router/pull/1585
+
 ### Fix typo on HTTP errors from subgraph ([#1593](https://github.com/apollographql/router/pull/1593))
 
 Remove the closed parenthesis at the end of error messages resulting from HTTP errors from subgraphs.

apollo-router/src/spec/query.rs

@@ -244,7 +244,7 @@ impl Query {
                 // we cannot know about the expected format of custom scalars
                 // so we must pass them directly to the client
                 if schema.custom_scalars.contains(type_name) {
-                    *output = input.take();
+                    *output = input.clone();
                     return Ok(());
                 } else if let Some(enum_type) = schema.enums.get(type_name) {
                     return match input.as_str() {
@@ -1339,6 +1339,32 @@ mod tests {
         );
     }
 
+    #[test]
+    fn reformat_response_array_of_scalar_duplicate_key() {
+        assert_format_response!(
+            "type Query {
+                get: Thing
+            }
+            type Thing {
+                array: [Int]
+            }
+
+            ",
+            "{get {array array}}",
+            json! {{
+                "get": {
+                    "array": [1,2,3,4],
+                },
+            }},
+            None,
+            json! {{
+                "get": {
+                    "array": [1,2,3,4],
+                },
+            }},
+        );
+    }
+
     #[test]
     fn reformat_response_array_of_type_simple() {
         assert_format_response!(