Send request to network when cache entry parsing fails (google#321)

* Send request to network if parsing a cache entry returns an error.

Also invalidate the corrupted cache entry and set the request's entry to null.

* Add request marker when cache entry parsing fails.

src/main/java/com/android/volley/CacheDispatcher.java

@@ -159,6 +159,15 @@ void processRequest(final Request<?> request) throws InterruptedException {
                             new NetworkResponse(entry.data, entry.responseHeaders));
             request.addMarker("cache-hit-parsed");
 
+            if (!response.isSuccess()) {
+                request.addMarker("cache-parsing-failed");
+                mCache.invalidate(request.getCacheKey(), true);
+                request.setCacheEntry(null);
+                if (!mWaitingRequestManager.maybeAddToWaitingRequests(request)) {
+                    mNetworkQueue.put(request);
+                }
+                return;
+            }
             if (!entry.refreshNeeded()) {
                 // Completely unexpired cache hit. Just deliver the response.
                 mDelivery.postResponse(request, response);

src/test/java/com/android/volley/CacheDispatcherTest.java

@@ -140,6 +140,25 @@ public void expiredCacheHit() throws Exception {
         assertSame(entry, mRequest.getCacheEntry());
     }
 
+    // An fresh cache hit with parse error, does not post a response and queues to the network.
+    @Test
+    public void freshCacheHit_parseError() throws Exception {
+        Request request = mock(Request.class);
+        when(request.parseNetworkResponse(any(NetworkResponse.class)))
+                .thenReturn(Response.error(new ParseError()));
+        when(request.getCacheKey()).thenReturn("cache/key");
+        Cache.Entry entry = CacheTestUtils.makeRandomCacheEntry(null, false, false);
+        when(mCache.get(anyString())).thenReturn(entry);
+
+        mDispatcher.processRequest(request);
+
+        verifyNoResponse(mDelivery);
+        verify(mNetworkQueue).put(request);
+        assertNull(request.getCacheEntry());
+        verify(mCache).invalidate("cache/key", true);
+        verify(request).addMarker("cache-parsing-failed");
+    }
+
     @Test
     public void duplicateCacheMiss() throws Exception {
         StringRequest secondRequest =