From 818a629f99043e7a855731253c30cc230c5e157c Mon Sep 17 00:00:00 2001
From: Luke Jones <luke@ljones.dev>
Date: Wed, 8 Sep 2021 12:43:04 +1200
Subject: [PATCH] Fix use of Null op when completedSteps used in initState

Fixes occurrence of "Unhandled Exception: Null check operator used on a null value" if `hasPreviouslyCompleted()` is used in the app initState before any steps have run.
---
 lib/src/foundation/persistence_provider.dart | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/src/foundation/persistence_provider.dart b/lib/src/foundation/persistence_provider.dart
index a0c8bee..58d1e8c 100644
--- a/lib/src/foundation/persistence_provider.dart
+++ b/lib/src/foundation/persistence_provider.dart
@@ -47,7 +47,10 @@ class SharedPreferencesProvider implements PersistenceProvider {
   @override
   Future<Set<String?>> completedSteps(Iterable<String?>? featuresIds) async {
     final prefs = await SharedPreferences.getInstance();
-    return featuresIds!
+    if (featuresIds == null) {
+      return Set();
+    }
+    return featuresIds
         .where((featureId) =>
             prefs.getBool(_normalizeFeatureId(featureId)) == true)
         .toSet();