accept null values for input values, closes #252 (#266)

server/src-lib/Hasura/GraphQL/Resolve/Mutation.hs

@@ -65,7 +65,8 @@ convertRowObj
   -> m [(PGCol, S.SQLExp)]
 convertRowObj val =
   flip withObject val $ \_ obj -> forM (Map.toList obj) $ \(k, v) -> do
-    prepExp <- asPGColVal v >>= prepare
+    prepExpM <- asPGColValM v >>= mapM prepare
+    let prepExp = fromMaybe (S.SEUnsafe "NULL") prepExpM
     return (PGCol $ G.unName k, prepExp)
 
 mkConflictClause

server/test/Spec.hs

@@ -51,6 +51,7 @@ gqlSpecFiles =
   , "insert_mutation/article_on_conflict_error_03.yaml"
   , "insert_mutation/person.yaml"
   , "insert_mutation/person_array.yaml"
+  , "insert_mutation/order.yaml"
   , "nested_select_query_article.yaml"
   , "select_query_article_limit_offset.yaml"
   , "select_query_article_limit_offset_error_01.yaml"

server/test/testcases/create_tables.yaml

@@ -50,3 +50,11 @@ query:
             city TEXT NOT NULL,
             resident_id INTEGER REFERENCES resident(id)
           )
+    - type: run_sql
+      args:
+        sql: |
+          CREATE TABLE orders (
+            id SERIAL PRIMARY KEY,
+            placed TIMESTAMPTZ NOT NULL,
+            shipped TIMESTAMPTZ
+          )

server/test/testcases/insert_mutation/order.yaml

@@ -0,0 +1,20 @@
+description: Insert into order table with a null value
+url: /v1alpha1/graphql
+status: 200
+query:
+  query: |
+    mutation insert_orders{
+      insert_orders(
+        objects: [
+          {
+            placed: "2017-08-19 14:22:11.802755+02",
+            shipped: null
+          }
+        ]
+      ) {
+        returning {
+          id
+        }
+        affected_rows
+      }
+    }

server/test/testcases/track_tables.yaml

@@ -24,4 +24,8 @@ query:
       args:
         schema: public
         name: address
+    - type: track_table
+      args:
+        schema: public
+        name: orders