commit d1b4b81680d90e857bd38e76fe9919802bc4c19c
author Ruslan Tkhakokhov <rthakohov@google.com> Fri Nov 29 14:44:37 2019 +0000
committer Ruslan Tkhakokhov <rthakohov@google.com> Fri Nov 29 17:36:01 2019 +0000
tree 069f485e041d2a44988f81f7e4643f40db5523b3
parent fef00238a180d9fb0eab15777807b4edf011bccf

Fix NPE while reading leftover journals in BMS

Thisis the NPE bug we saw a while ago but it  has been coming up in test runs recently (b/). Let's fix the NPE for now and we can work on the underlying issue later.

Bug: 136730045
Test: atest DataChangedJournalTest
Change-Id: I7267f507be4c797491d86ebb8bc5e6c3c17652a3

services/backup/java/com/android/server/backup/DataChangedJournal.java

diff --git a/services/backup/java/com/android/server/backup/DataChangedJournal.java b/services/backup/java/com/android/server/backup/DataChangedJournal.java
index 498185c..e75eb73 100644
--- a/services/backup/java/com/android/server/backup/DataChangedJournal.java
+++ b/services/backup/java/com/android/server/backup/DataChangedJournal.java
@@ -17,6 +17,7 @@
 package com.android.server.backup;
 
 import android.annotation.Nullable;
+import android.util.Slog;
 
 import java.io.BufferedInputStream;
 import java.io.DataInputStream;
@@ -36,6 +37,7 @@
  * reboot.
  */
 public class DataChangedJournal {
+    private static final String TAG = "DataChangedJournal";
     private static final String FILE_NAME_PREFIX = "journal";
 
     /**
@@ -139,7 +141,12 @@
      */
     static ArrayList<DataChangedJournal> listJournals(File journalDirectory) {
         ArrayList<DataChangedJournal> journals = new ArrayList<>();
-        for (File file : journalDirectory.listFiles()) {
+        File[] journalFiles = journalDirectory.listFiles();
+        if (journalFiles == null) {
+            Slog.w(TAG, "Failed to read journal files");
+            return journals;
+        }
+        for (File file : journalFiles) {
             journals.add(new DataChangedJournal(file));
         }
         return journals;

services/tests/servicestests/src/com/android/server/backup/DataChangedJournalTest.java

diff --git a/services/tests/servicestests/src/com/android/server/backup/DataChangedJournalTest.java b/services/tests/servicestests/src/com/android/server/backup/DataChangedJournalTest.java
index f588c4f..4e7fe44 100644
--- a/services/tests/servicestests/src/com/android/server/backup/DataChangedJournalTest.java
+++ b/services/tests/servicestests/src/com/android/server/backup/DataChangedJournalTest.java
@@ -18,6 +18,9 @@
 
 import static com.google.common.truth.Truth.assertThat;
 
+import static org.mockito.Mockito.when;
+import static org.testng.Assert.assertEquals;
+
 import android.platform.test.annotations.Presubmit;
 
 import androidx.test.filters.SmallTest;
@@ -50,6 +53,7 @@
     @Rule public TemporaryFolder mTemporaryFolder = new TemporaryFolder();
 
     @Mock private Consumer<String> mConsumer;
+    @Mock private File invalidFile;
 
     private File mFile;
     private DataChangedJournal mJournal;
@@ -131,4 +135,10 @@
     public void toString_isSameAsFileToString() throws Exception {
         assertThat(mJournal.toString()).isEqualTo(mFile.toString());
     }
+
+    public void listJournals_invalidJournalFile_returnsEmptyList() throws Exception {
+        when(invalidFile.listFiles()).thenReturn(null);
+
+        assertEquals(0, DataChangedJournal.listJournals(invalidFile).size());
+    }
 }