Fix system_views.settings to handle array types

patch by Stefan Miklosovic; reviewed by Brandon Williams for CASSANDRA-19475

CHANGES.txt

@@ -1,4 +1,5 @@
 4.1.5
+ * Fix system_views.settings to handle array types (CASSANDRA-19475)
 Merged from 4.0:
  * Push LocalSessions info logs to debug (CASSANDRA-18335)
  * Filter remote DC replicas out when constructing the initial replica plan for the local read repair (CASSANDRA-19120)

src/java/org/apache/cassandra/db/virtual/SettingsTable.java

@@ -17,9 +17,12 @@
  */
 package org.apache.cassandra.db.virtual;
 
+import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
+
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.ImmutableMap;
 
 import org.apache.cassandra.config.Config;
@@ -83,10 +86,17 @@ final class SettingsTable extends AbstractVirtualTable
         return result;
     }
 
-    private String getValue(Property prop)
+    @VisibleForTesting
+    String getValue(Property prop)
     {
         Object value = prop.get(config);
-        return value == null ? null : value.toString();
+        if (value == null)
+            return null;
+
+        if (value.getClass().isArray())
+            return Arrays.asList((Object[]) value).toString();
+
+        return value.toString();
     }
 
     private static Map<String, Property> getProperties()

test/unit/org/apache/cassandra/db/virtual/SettingsTableTest.java

@@ -62,11 +62,19 @@ public class SettingsTableTest extends CQLTester
         config.cache_load_timeout = new DurationSpec.IntSecondsBound(0);
         config.commitlog_sync_group_window = new DurationSpec.IntMillisecondsBound(0);
         config.credentials_update_interval = null;
+        config.data_file_directories = new String[] {"/my/data/directory", "/another/data/directory"};
         table = new SettingsTable(KS_NAME, config);
         VirtualKeyspaceRegistry.instance.register(new VirtualKeyspace(KS_NAME, ImmutableList.of(table)));
         disablePreparedReuseForTest();
     }
 
+    @Test
+    public void testArray() throws Throwable
+    {
+        Row one = executeNet("SELECT value FROM vts.settings WHERE name = 'data_file_directories'").one();
+        Assert.assertEquals("[/my/data/directory, /another/data/directory]", one.getString("value"));
+    }
+
     @Test
     public void testSelectAll() throws Throwable
     {
@@ -79,7 +87,7 @@ public class SettingsTableTest extends CQLTester
             String name = r.getString("name");
             Property prop = SettingsTable.PROPERTIES.get(name);
             if (prop != null) // skip overrides
-                Assert.assertEquals(getValue(prop), r.getString("value"));
+                Assert.assertEquals(table.getValue(prop), r.getString("value"));
         }
         Assert.assertTrue(SettingsTable.PROPERTIES.size() <= i);
     }
@@ -92,7 +100,7 @@ public class SettingsTableTest extends CQLTester
             String name = e.getKey();
             Property prop = e.getValue();
             String q = "SELECT * FROM vts.settings WHERE name = '"+name+'\'';
-            assertRowsNet(executeNet(q), new Object[] { name, getValue(prop) });
+            assertRowsNet(executeNet(q), new Object[] { name, table.getValue(prop) });
         }
     }
 
@@ -146,14 +154,6 @@ public class SettingsTableTest extends CQLTester
         assertRowsNet(executeNet(q), new Object[] {"credentials_update_interval_in_ms", "-1"});
     }
 
-    private String getValue(Property prop)
-    {
-        Object v = prop.get(config);
-        if (v != null)
-            return v.toString();
-        return null;
-    }
-
     private void check(String setting, String expected) throws Throwable
     {
         String q = "SELECT * FROM vts.settings WHERE name = '"+setting+'\'';