Upgrade to OperationContext and remove duplicate fields to fix #1161

docs/content/reference/field-collection.md

@@ -61,19 +61,21 @@ The type `Circle` would satisfy `Circle`, `Shape`, and `Shapes` — these values
 Say we have the following GraphQL query
 
 ```graphql
-flowBlocks {
-	id
-	block{
-		id
-		title
-		type
-		choices{
-			id
-			title
-			description
-			slug
-		}
-	}
+query {
+  flowBlocks {
+    id
+    block {
+      id
+      title
+      type
+      choices {
+        id
+        title
+        description
+        slug
+      }
+    }
+  }
 }
 ```
 
@@ -83,19 +85,17 @@ Here is an example which get's all requested field as convenient string slice, w
 ```golang
 func GetPreloads(ctx context.Context) []string {
 	return GetNestedPreloads(
-		graphql.GetRequestContext(ctx),
+		graphql.GetOperationContext(ctx),
 		graphql.CollectFieldsCtx(ctx, nil),
 		"",
 	)
 }
 
-func GetNestedPreloads(ctx *graphql.RequestContext, fields []graphql.CollectedField, prefix string) (preloads []string) {
+func GetNestedPreloads(ctx *graphql.OperationContext, fields []graphql.CollectedField, prefix string) (preloads []string) {
 	for _, column := range fields {
 		prefixColumn := GetPreloadString(prefix, column.Name)
 		preloads = append(preloads, prefixColumn)
-		preloads = append(preloads, GetNestedPreloads(ctx, graphql.CollectFields(ctx, column.SelectionSet, nil), prefixColumn)...)
 		preloads = append(preloads, GetNestedPreloads(ctx, graphql.CollectFields(ctx, column.Selections, nil), prefixColumn)...)
-
 	}
 	return
 }