From 52742ec890f80677336b4c58c240772769c3747f Mon Sep 17 00:00:00 2001
From: Julia Reynolds <juliacr@google.com>
Date: Tue, 2 Feb 2021 11:56:54 -0500
Subject: [PATCH] Fix NPE

The parent channel of a conversation can be deleted; we should still show the
customized channel if the app didn't choose to delete that as well.

Test: PreferencesHelperTest
Fixes: 179127295
Change-Id: If4a3c16c37126096a34aefa2f97da0c4ce081545
---
 .../notification/PreferencesHelper.java       |  6 +++--
 .../notification/PreferencesHelperTest.java   | 22 +++++++++++++++++++
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/services/core/java/com/android/server/notification/PreferencesHelper.java b/services/core/java/com/android/server/notification/PreferencesHelper.java
index 61c8b178b4c0d..461d51912983f 100644
--- a/services/core/java/com/android/server/notification/PreferencesHelper.java
+++ b/services/core/java/com/android/server/notification/PreferencesHelper.java
@@ -1419,8 +1419,10 @@ public class PreferencesHelper implements RankingConfig {
                             conversation.setPkg(p.pkg);
                             conversation.setUid(p.uid);
                             conversation.setNotificationChannel(nc);
-                            conversation.setParentChannelLabel(
-                                    p.channels.get(nc.getParentChannelId()).getName());
+                            NotificationChannel parent = p.channels.get(nc.getParentChannelId());
+                            conversation.setParentChannelLabel(parent == null
+                                    ? null
+                                    : parent.getName());
                             boolean blockedByGroup = false;
                             if (nc.getGroup() != null) {
                                 NotificationChannelGroup group = p.groups.get(nc.getGroup());
diff --git a/services/tests/uiservicestests/src/com/android/server/notification/PreferencesHelperTest.java b/services/tests/uiservicestests/src/com/android/server/notification/PreferencesHelperTest.java
index 8c744c94249b3..fc1cb70cf7462 100644
--- a/services/tests/uiservicestests/src/com/android/server/notification/PreferencesHelperTest.java
+++ b/services/tests/uiservicestests/src/com/android/server/notification/PreferencesHelperTest.java
@@ -3536,6 +3536,28 @@ public class PreferencesHelperTest extends UiServiceTestCase {
         assertFalse(conversationWrapperContainsChannel(convos, channel2));
     }
 
+    @Test
+    public void testGetConversations_parentDeleted() {
+        String convoId = "convo";
+        NotificationChannel messages =
+                new NotificationChannel("messages", "Messages", IMPORTANCE_DEFAULT);
+        mHelper.createNotificationChannel(PKG_O, UID_O, messages, true, false);
+
+        NotificationChannel channel =
+                new NotificationChannel("A person msgs", "messages from A", IMPORTANCE_DEFAULT);
+        channel.setConversationId(messages.getId(), convoId);
+        channel.setImportantConversation(true);
+        mHelper.createNotificationChannel(PKG_O, UID_O, channel, true, false);
+
+        mHelper.permanentlyDeleteNotificationChannel(PKG_O, UID_O, "messages");
+
+        List<ConversationChannelWrapper> convos =
+                mHelper.getConversations(IntArray.wrap(new int[] {0}), true);
+
+        assertEquals(1, convos.size());
+        assertTrue(conversationWrapperContainsChannel(convos, channel));
+    }
+
     private boolean conversationWrapperContainsChannel(List<ConversationChannelWrapper> list,
             NotificationChannel expected) {
         for (ConversationChannelWrapper ccw : list) {