Fix issue with query watcher for empty cache (#915)

If cache is empty re-fetch any watcher that has empty dependent key set. Closes #822
apollographql · May 13, 2018 · 283a43f · 283a43f
1 parent 06be422
commit 283a43f
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Showing 4 changed files with 50 additions and 2 deletions.
diff --git a/apollo-integration/src/test/java/com/apollographql/apollo/ApolloWatcherTest.java b/apollo-integration/src/test/java/com/apollographql/apollo/ApolloWatcherTest.java
@@ -1,5 +1,6 @@
 package com.apollographql.apollo;
 
+import com.apollographql.apollo.api.Input;
 import com.apollographql.apollo.api.Response;
 import com.apollographql.apollo.api.internal.Optional;
 import com.apollographql.apollo.cache.CacheHeaders;
@@ -40,6 +41,7 @@
 import static com.apollographql.apollo.fetcher.ApolloResponseFetchers.CACHE_ONLY;
 import static com.apollographql.apollo.fetcher.ApolloResponseFetchers.NETWORK_ONLY;
 import static com.google.common.truth.Truth.assertThat;
+import static junit.framework.Assert.fail;
 
 public class ApolloWatcherTest {
   private ApolloClient apolloClient;
@@ -338,4 +340,39 @@ public void testQueryWatcherNotCalled_WhenCanceled() throws Exception {
     assertThat(heroNameList.get(0)).isEqualTo("R2-D2");
     assertThat(heroNameList.size()).isEqualTo(1);
   }
+
+  @Test
+  public void emptyCacheQueryWatcherCacheOnly() throws Exception {
+    final List<EpisodeHeroNameQuery.Hero> watchedHeroes = new ArrayList<>();
+    EpisodeHeroNameQuery query = new EpisodeHeroNameQuery(Input.fromNullable(Episode.EMPIRE));
+    apolloClient.query(query)
+        .responseFetcher(CACHE_ONLY)
+        .watcher()
+        .enqueueAndWatch(new ApolloCall.Callback<EpisodeHeroNameQuery.Data>() {
+          @Override public void onResponse(Response<EpisodeHeroNameQuery.Data> response) {
+            if (response.data() != null) {
+              watchedHeroes.add(response.data().hero());
+            }
+          }
+
+          @Override public void onFailure(ApolloException e) {
+            fail(e.getMessage());
+          }
+        });
+
+    server.enqueue(mockResponse("EpisodeHeroNameResponseWithId.json"));
+    apolloClient.query(query).enqueue(new ApolloCall.Callback<EpisodeHeroNameQuery.Data>() {
+      @Override public void onResponse(Response<EpisodeHeroNameQuery.Data> response) {
+        assertThat(response.data()).isNotNull();
+        assertThat(response.data().hero()).isNotNull();
+      }
+
+      @Override public void onFailure(ApolloException e) {
+        fail(e.getMessage());
+      }
+    });
+
+    assertThat(watchedHeroes).hasSize(1);
+    assertThat(watchedHeroes.get(0).name()).isEqualTo("R2-D2");
+  }
 }
diff --git a/apollo-runtime/src/main/java/com/apollographql/apollo/cache/normalized/Record.java b/apollo-runtime/src/main/java/com/apollographql/apollo/cache/normalized/Record.java
@@ -127,6 +127,17 @@ public Set<String> mergeWith(Record otherRecord) {
     return changedKeys;
   }
 
+  /**
+   * @return A set of all field keys. A field key incorporates any GraphQL arguments in addition to the field name.
+   */
+  public Set<String> keys() {
+    Set<String> keys = new HashSet<>();
+    for (Map.Entry<String, Object> field : fields.entrySet()) {
+      keys.add(key() + "." + field.getKey());
+    }
+    return keys;
+  }
+
   /**
    * @return A map of fieldName to fieldValue. Where fieldValue is a GraphQL Scalar or {@link CacheReference} if it is a
    * GraphQL Object type.

diff --git a/...ntime/src/main/java/com/apollographql/apollo/cache/normalized/lru/LruNormalizedCache.java b/...ntime/src/main/java/com/apollographql/apollo/cache/normalized/lru/LruNormalizedCache.java
@@ -117,7 +117,7 @@ protected Set<String> performMerge(@Nonnull final Record apolloRecord, @Nonnull
     final Record oldRecord = lruCache.getIfPresent(apolloRecord.key());
     if (oldRecord == null) {
       lruCache.put(apolloRecord.key(), apolloRecord);
-      return Collections.emptySet();
+      return apolloRecord.keys();
     } else {
       Set<String> changedKeys = oldRecord.mergeWith(apolloRecord);
 

diff --git a/apollo-runtime/src/main/java/com/apollographql/apollo/internal/RealApolloQueryWatcher.java b/apollo-runtime/src/main/java/com/apollographql/apollo/internal/RealApolloQueryWatcher.java
@@ -37,7 +37,7 @@ final class RealApolloQueryWatcher<T> implements ApolloQueryWatcher<T> {
   private final ApolloCallTracker tracker;
   final ApolloStore.RecordChangeSubscriber recordChangeSubscriber = new ApolloStore.RecordChangeSubscriber() {
     @Override public void onCacheRecordsChanged(Set<String> changedRecordKeys) {
-      if (!Utils.areDisjoint(dependentKeys, changedRecordKeys)) {
+      if (dependentKeys.isEmpty() || !Utils.areDisjoint(dependentKeys, changedRecordKeys)) {
         refetch();
       }
     }