fix: null handling in the resolvers

src/blueprint/blueprint.rs

@@ -53,6 +53,14 @@ impl Type {
             Type::ListType { non_null, .. } => *non_null,
         }
     }
+
+    /// checks if the type is a list
+    pub fn is_list(&self) -> bool {
+        match self {
+            Type::NamedType { .. } => false,
+            Type::ListType { .. } => true,
+        }
+    }
 }
 
 #[derive(Clone, Debug)]

src/blueprint/into_schema.rs

@@ -41,6 +41,7 @@ fn to_type(def: &Definition) -> dynamic::Type {
                 let field = field.clone();
                 let type_ref = to_type_ref(&field.of_type);
                 let field_name = &field.name.clone();
+                let is_list = field.of_type.is_list();
                 let mut dyn_schema_field = dynamic::Field::new(
                     field_name,
                     type_ref.clone(),
@@ -70,12 +71,17 @@ fn to_type(def: &Definition) -> dynamic::Type {
 
                                         let const_value =
                                             expr.eval(ctx, &Concurrent::Sequential).await?;
-
                                         let p = match const_value {
-                                            ConstValue::List(a) => FieldValue::list(a),
-                                            a => FieldValue::from(a),
+                                            ConstValue::List(a) => Some(FieldValue::list(a)),
+                                            a => {
+                                                if a == ConstValue::Null && is_list {
+                                                     FieldValue::NONE
+                                                } else {
+                                                    FieldValue::try_from(a).ok()
+                                                }
+                                            },
                                         };
-                                        Ok(Some(p))
+                                        Ok(p)
                                     }
                                     .instrument(span)
                                     .inspect_err(|err| tracing::error!(?err)),

src/http/response.rs

@@ -34,7 +34,14 @@ impl Response<Bytes> {
         }
     }
 
-    pub fn to_json<T: DeserializeOwned>(self) -> Result<Response<T>> {
+    pub fn to_json<T: DeserializeOwned + Default>(self) -> Result<Response<T>> {
+        if self.body.is_empty() {
+            return Ok(Response {
+                status: self.status,
+                headers: self.headers,
+                body: Default::default(),
+            });
+        }
         let body = serde_json::from_slice::<T>(&self.body)?;
         Ok(Response { status: self.status, headers: self.headers, body })
     }

tests/execution/test-null-in-array.md

@@ -0,0 +1,30 @@
+# Empty Array Response
+
+```graphql @server
+schema @server {
+  query: Query
+}
+
+type Query {
+  hi(id: ID!): [Company] @http(baseURL: "http://localhost:3000", path: "/hi")
+}
+type Company {
+  name: String
+  id: ID
+}
+```
+
+```yml @mock
+- request:
+    method: GET
+    url: http://localhost:3000/hi
+  response:
+    status: 200
+```
+
+```yml @test
+- method: POST
+  url: http://localhost:8080/graphql
+  body:
+    query: "query { hi (id: 1) { name id } }"
+```

tests/execution/test-null-in-object.md

@@ -0,0 +1,30 @@
+# Empty Object Response
+
+```graphql @server
+schema @server {
+  query: Query
+}
+
+type Query {
+  hi(id: ID!): Company @http(baseURL: "http://localhost:3000", path: "/hi")
+}
+type Company {
+  name: String
+  id: ID
+}
+```
+
+```yml @mock
+- request:
+    method: GET
+    url: http://localhost:3000/hi
+  response:
+    status: 200
+```
+
+```yml @test
+- method: POST
+  url: http://localhost:8080/graphql
+  body:
+    query: "query { hi (id: 1) { name id } }"
+```

tests/snapshots/execution_spec__test-null-in-array.md_client.snap

@@ -0,0 +1,28 @@
+---
+source: tests/execution_spec.rs
+expression: client
+---
+type Company {
+  id: ID
+  name: String
+}
+
+scalar Date
+
+scalar Email
+
+scalar Empty
+
+scalar JSON
+
+scalar PhoneNumber
+
+type Query {
+  hi(id: ID!): [Company]
+}
+
+scalar Url
+
+schema {
+  query: Query
+}

tests/snapshots/execution_spec__test-null-in-array.md_merged.snap

@@ -0,0 +1,16 @@
+---
+source: tests/execution_spec.rs
+expression: merged
+---
+schema @server @upstream {
+  query: Query
+}
+
+type Company {
+  id: ID
+  name: String
+}
+
+type Query {
+  hi(id: ID!): [Company] @http(baseURL: "http://localhost:3000", path: "/hi")
+}

tests/snapshots/execution_spec__test-null-in-array.md_test_0.snap

@@ -0,0 +1,15 @@
+---
+source: tests/execution_spec.rs
+expression: response
+---
+{
+  "status": 200,
+  "headers": {
+    "content-type": "application/json"
+  },
+  "body": {
+    "data": {
+      "hi": null
+    }
+  }
+}

tests/snapshots/execution_spec__test-null-in-object.md_client.snap

@@ -0,0 +1,28 @@
+---
+source: tests/execution_spec.rs
+expression: client
+---
+type Company {
+  id: ID
+  name: String
+}
+
+scalar Date
+
+scalar Email
+
+scalar Empty
+
+scalar JSON
+
+scalar PhoneNumber
+
+type Query {
+  hi(id: ID!): Company
+}
+
+scalar Url
+
+schema {
+  query: Query
+}

tests/snapshots/execution_spec__test-null-in-object.md_merged.snap

@@ -0,0 +1,16 @@
+---
+source: tests/execution_spec.rs
+expression: merged
+---
+schema @server @upstream {
+  query: Query
+}
+
+type Company {
+  id: ID
+  name: String
+}
+
+type Query {
+  hi(id: ID!): Company @http(baseURL: "http://localhost:3000", path: "/hi")
+}

tests/snapshots/execution_spec__test-null-in-object.md_test_0.snap

@@ -0,0 +1,18 @@
+---
+source: tests/execution_spec.rs
+expression: response
+---
+{
+  "status": 200,
+  "headers": {
+    "content-type": "application/json"
+  },
+  "body": {
+    "data": {
+      "hi": {
+        "name": null,
+        "id": null
+      }
+    }
+  }
+}