From 107892653e275349638cf703482d2c91573d25a3 Mon Sep 17 00:00:00 2001
From: Maxim Filipenko <proktusfahitasiv@gmail.com>
Date: Thu, 4 Mar 2021 01:41:08 +0300
Subject: [PATCH] Fix "error adding scrub fields" for aliases (#126)

Co-authored-by: Maxim Filipenko <prokaktus@Maxims-MBP.Dlink>
---
 plan.go      |  2 +-
 plan_test.go | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 1 deletion(-)

diff --git a/plan.go b/plan.go
index d413a17..70a9bdc 100644
--- a/plan.go
+++ b/plan.go
@@ -819,7 +819,7 @@ func (p *MinQueriesPlanner) generateScrubFieldsWalk(step *QueryPlanStep, selecti
 		// look over the points in the selection
 		for _, field := range graphql.SelectedFields(targetSelection) {
 			// if the field name is what we expected
-			if field.Name == point {
+			if field.Name == point || field.Alias == point {
 				// our next selection set is the fields selection set
 				targetSelection = field.SelectionSet
 
diff --git a/plan_test.go b/plan_test.go
index 99b3fda..ad9864c 100644
--- a/plan_test.go
+++ b/plan_test.go
@@ -1687,3 +1687,69 @@ func TestPlanQuery_forcedPriorityResolution(t *testing.T) {
 	assert.Equal(t, "lastName", lastNameField.Name)
 	assert.Equal(t, location2, lastNameStep.Queryer.(*graphql.SingleRequestQueryer).URL())
 }
+
+func TestPlanQuery_scrubWithAlias(t *testing.T) {
+	schema, _ := graphql.LoadSchema(`
+		type User {
+			firstName: String!
+			catPhotos: [CatPhoto!]!
+		}
+
+		type CatPhoto {
+			URL: String!
+		}
+
+		type Query {
+			allUsers: [User!]!
+		}
+	`)
+
+	// the location of the user service
+	userLocation := "user-location"
+	// the location of the cat service
+	catLocation := "cat-location"
+
+	// the location map for fields for this query
+	locations := FieldURLMap{}
+	locations.RegisterURL("Query", "allUsers", userLocation)
+	locations.RegisterURL("User", "firstName", userLocation)
+	locations.RegisterURL("User", "catPhotos", catLocation)
+	locations.RegisterURL("CatPhoto", "URL", catLocation)
+	locations.RegisterURL("CatPhoto", "name", catLocation)
+
+	plans, err := (&MinQueriesPlanner{}).Plan(&PlanningContext{
+		Query: `
+			{
+				users: allUsers {
+					firstName
+					catPhotos {
+						URL
+					}
+				}
+			}
+		`,
+		Schema:    schema,
+		Locations: locations,
+	})
+	// if something went wrong planning the query
+	if err != nil {
+		// the test is over
+		t.Errorf("encountered error when building schema: %s", err.Error())
+		return
+	}
+
+	// the first step should have all users
+	firstStep := plans[0].RootStep.Then[0]
+	// make sure we are grabbing values off of Query since its the root
+	assert.Equal(t, "Query", firstStep.ParentType)
+
+	// make sure there's a selection set
+	if len(firstStep.SelectionSet) != 1 {
+		t.Error("first step did not have a selection set")
+		return
+	}
+	// check that allUsers selected and alias presented
+	firstField := graphql.SelectedFields(firstStep.SelectionSet)[0]
+	assert.Equal(t, "allUsers", firstField.Name)
+	assert.Equal(t, "users", firstField.Alias)
+}