Add aws.StringValue wrapper to prevent crash on missing environment name

aws/ecs_task_definition_equivalency.go

@@ -78,7 +78,7 @@ func (cd containerDefinitions) Reduce(isAWSVPC bool) error {
 
 		// Deal with fields which may be re-ordered in the API
 		sort.Slice(def.Environment, func(i, j int) bool {
-			return *def.Environment[i].Name < *def.Environment[j].Name
+			return aws.StringValue(def.Environment[i].Name) < aws.StringValue(def.Environment[j].Name)
 		})
 
 		// Create a mutable copy

aws/ecs_task_definition_equivalency_test.go

@@ -474,3 +474,90 @@ func TestAwsEcsContainerDefinitionsAreEquivalent_negative(t *testing.T) {
 		t.Fatal("Expected definitions to differ.")
 	}
 }
+
+func TestAwsEcsContainerDefinitionsAreEquivalent_missingEnvironmentName(t *testing.T) {
+	cfgRepresention := `
+[
+    {
+      "name": "wordpress",
+      "links": [
+        "mysql"
+      ],
+      "image": "wordpress",
+      "essential": true,
+      "portMappings": [
+        {
+          "containerPort": 80,
+          "hostPort": 80
+        }
+      ],
+      "memory": 500,
+      "cpu": 10
+    },
+    {
+      "environment": [
+        {
+          "value": "password"
+        },
+        {
+          "value": "password2"
+        }
+      ],
+      "name": "mysql",
+      "image": "mysql",
+      "cpu": 10,
+      "memory": 500,
+      "essential": true
+    }
+]`
+
+	apiRepresentation := `
+[
+    {
+        "name": "wordpress",
+        "image": "wordpress",
+        "cpu": 10,
+        "memory": 500,
+        "links": [
+            "mysql"
+        ],
+        "portMappings": [
+            {
+                "containerPort": 80,
+                "hostPort": 80,
+                "protocol": "tcp"
+            }
+        ],
+        "essential": true,
+        "environment": [],
+        "mountPoints": [],
+        "volumesFrom": []
+    },
+    {
+        "name": "mysql",
+        "image": "mysql",
+        "cpu": 10,
+        "memory": 500,
+        "portMappings": [],
+        "essential": true,
+        "environment": [
+          {
+            "value": "password"
+          },
+          {
+            "value": "password2"
+          }
+        ],
+        "mountPoints": [],
+        "volumesFrom": []
+    }
+]`
+
+	equal, err := EcsContainerDefinitionsAreEquivalent(cfgRepresention, apiRepresentation, false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !equal {
+		t.Fatal("Expected definitions to be equal.")
+	}
+}