Check for missing metadata when constructing ConfigContainer. (#2217)

Author: danasilver

firebase-config/src/main/java/com/google/firebase/remoteconfig/internal/ConfigContainer.java

@@ -86,11 +86,18 @@ private ConfigContainer(
    * <p>The {@code containerJson} must not be modified.
    */
   static ConfigContainer copyOf(JSONObject containerJson) throws JSONException {
+    // Personalization metadata may not have been written yet.
+    JSONObject personalizationMetadataJSON =
+        containerJson.optJSONObject(PERSONALIZATION_METADATA_KEY);
+    if (personalizationMetadataJSON == null) {
+      personalizationMetadataJSON = new JSONObject();
+    }
+
     return new ConfigContainer(
         containerJson.getJSONObject(CONFIGS_KEY),
         new Date(containerJson.getLong(FETCH_TIME_KEY)),
         containerJson.getJSONArray(ABT_EXPERIMENTS_KEY),
-        containerJson.getJSONObject(PERSONALIZATION_METADATA_KEY));
+        personalizationMetadataJSON);
   }
 
   /**

firebase-config/src/test/java/com/google/firebase/remoteconfig/internal/ConfigStorageClientTest.java

@@ -23,8 +23,11 @@
 import java.io.BufferedReader;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
 import java.io.InputStreamReader;
+import java.nio.charset.StandardCharsets;
 import java.util.Date;
+import org.json.JSONObject;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -82,6 +85,36 @@ public void read_validContainer_returnsContainer() throws Exception {
     assertThat(container).isEqualTo(configContainer);
   }
 
+  @Test
+  public void read_validContainerWithPersonalization_returnsContainer() throws Exception {
+    ConfigContainer configWithPersonalization =
+        ConfigContainer.newBuilder(configContainer)
+            .withPersonalizationMetadata(
+                new JSONObject(ImmutableMap.of(Personalization.ARM_KEY, "arm_value")))
+            .build();
+    storageClient.write(configWithPersonalization);
+    Preconditions.checkArgument(getFileAsString().equals(configWithPersonalization.toString()));
+
+    ConfigContainer container = storageClient.read();
+    assertThat(container).isEqualTo(configWithPersonalization);
+  }
+
+  @Test
+  public void read_validContainerWithoutPersonalization_returnsContainer() throws Exception {
+    // Configs written by SDK versions <20.0.1 do not contain personalization metadata.
+    // Since the serialized configContainer contains personalization metadata, we manually remove it
+    // and write the config to disk directly to test.
+    JSONObject configJSON = new JSONObject(configContainer.toString());
+    configJSON.remove(ConfigContainer.PERSONALIZATION_METADATA_KEY);
+
+    try (FileOutputStream outputStream = context.openFileOutput(FILE_NAME, Context.MODE_PRIVATE)) {
+      outputStream.write(configJSON.toString().getBytes(StandardCharsets.UTF_8));
+    }
+
+    ConfigContainer container = storageClient.read();
+    assertThat(container).isEqualTo(configContainer);
+  }
+
   @Test
   public void read_emptyFile_returnsNull() throws Exception {
     ConfigContainer container = storageClient.read();