Merge "fix FileNotFound exception when attempting to read bubble xml" into rvc-dev am: 750b4c93ec

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/11758287

Change-Id: Ibc8d9c298090c9c8df132208078a7d9a3637bc56

packages/SystemUI/src/com/android/systemui/bubbles/storage/BubblePersistentRepository.kt

@@ -54,6 +54,7 @@ class BubblePersistentRepository @Inject constructor(
 
     fun readFromDisk(): List<BubbleEntity> {
         synchronized(bubbleFile) {
+            if (!bubbleFile.exists()) return emptyList()
             try { return bubbleFile.openRead().use(::readXml) } catch (e: Throwable) {
                 Log.e(TAG, "Failed to open bubble file", e)
             }

packages/SystemUI/tests/src/com/android/systemui/bubbles/storage/BubblePersistentRepositoryTest.kt

@@ -20,6 +20,8 @@ import android.testing.AndroidTestingRunner
 import androidx.test.filters.SmallTest
 import com.android.systemui.SysuiTestCase
 import junit.framework.Assert.assertEquals
+import junit.framework.Assert.assertNotNull
+import junit.framework.Assert.assertTrue
 import org.junit.Before
 import org.junit.Test
 import org.junit.runner.RunWith
@@ -42,6 +44,11 @@ class BubblePersistentRepositoryTest : SysuiTestCase() {
 
     @Test
     fun testReadWriteOperation() {
+        // Verify read before write doesn't cause FileNotFoundException
+        val actual = repository.readFromDisk()
+        assertNotNull(actual)
+        assertTrue(actual.isEmpty())
+
         repository.persistsToDisk(bubbles)
         assertEquals(bubbles, repository.readFromDisk())
     }