Don't notify jobs of failures decoding from cache.

Since we also try to reload the image from source,
we may end up reporting first a failure and then
a success which would leave the request in an
undefined state.

library/src/androidTest/java/com/bumptech/glide/load/engine/ResourceRunnerTest.java

@@ -179,7 +179,7 @@ public class ResourceRunnerTest {
     }
 
     @Test
-    public void testNotifiesJobOfFailureIfCacheLoaderThrows() {
+    public void testSubmitsSourceRunnerIfCacheLoaderThrows() {
         final Exception exception = new IOException("test");
         when(harness.cacheLoader.load(any(Key.class), any(ResourceDecoder.class), anyInt(), anyInt())).thenAnswer(
                 new Answer<Object>() {
@@ -189,11 +189,12 @@ public class ResourceRunnerTest {
                     }
                 });
         harness.runner.run();
-        verify(harness.engineJob).onException(eq(exception));
+
+        verify(harness.resizeService).submit(eq(harness.sourceRunner));
     }
 
     @Test
-    public void testNotifiesJobOfFailureIfTransformationThrows() {
+    public void testSubmitsSourceRunnerIfTransformationThrows() {
         final Exception exception = new RuntimeException("test");
         when(harness.tranformation.transform(any(Resource.class), anyInt(), anyInt())).thenAnswer(new Answer<Object>() {
             @Override
@@ -202,11 +203,11 @@ public class ResourceRunnerTest {
             }
         });
         harness.runner.run();
-        verify(harness.engineJob).onException(eq(exception));
+        verify(harness.resizeService).submit(eq(harness.sourceRunner));
     }
 
     @Test
-    public void testNotifiesJobOfFailureIfTranscoderThrows() {
+    public void testSubmitsSourceRunnerIfTranscoderThrows() {
         final Exception exception = new RuntimeException("test");
         when(harness.transcoder.transcode(any(Resource.class))).thenAnswer(new Answer<Object>() {
             @Override
@@ -215,7 +216,7 @@ public class ResourceRunnerTest {
             }
         });
         harness.runner.run();
-        verify(harness.engineJob).onException(eq(exception));
+        verify(harness.resizeService).submit(eq(harness.sourceRunner));
     }
 
     @Test
@@ -232,6 +233,15 @@ public class ResourceRunnerTest {
         verify(harness.engineJob).onException(eq(exception));
     }
 
+    @Test
+    public void testDoesNotNotifyJobOfFailureIfDecodingFromCacheThrows() {
+        when(harness.cacheLoader.load(any(Key.class), any(ResourceDecoder.class), anyInt(), anyInt()))
+                .thenThrow(new RuntimeException("test"));
+
+        harness.runner.run();
+        verify(harness.engineJob, never()).onException(any(Exception.class));
+    }
+
     @SuppressWarnings("unchecked")
     private static class ResourceRunnerHarness {
         EngineKey key = mock(EngineKey.class);

library/src/main/java/com/bumptech/glide/load/engine/ResourceRunner.java

@@ -83,8 +83,11 @@ class ResourceRunner<Z, R> implements Runnable, Prioritized {
         try {
             result = runWrapped();
         } catch (Exception e) {
-            job.onException(e);
+            if (Log.isLoggable(TAG, Log.DEBUG)) {
+                Log.d(TAG, "Failed to decode resource from cache", e);
+            }
         }
+
         if (result != null) {
             job.onResourceReady(result);
         } else {