Handle NULL in ResultSet's getDate() method (#50184)

(cherry picked from commit 08214eb)

Author: astefan

x-pack/plugin/sql/jdbc/src/main/java/org/elasticsearch/xpack/sql/jdbc/JdbcResultSet.java

@@ -259,6 +259,11 @@ public Date getDate(String columnLabel) throws SQLException {
     private Long dateTimeAsMillis(int columnIndex) throws SQLException {
         Object val = column(columnIndex);
         EsType type = columnType(columnIndex);
+        
+        if (val == null) {
+            return null;
+        }
+        
         try {
             // TODO: the B6 appendix of the jdbc spec does mention CHAR, VARCHAR, LONGVARCHAR, DATE, TIMESTAMP as supported
             // jdbc types that should be handled by getDate and getTime methods. From all of those we support VARCHAR and
@@ -267,9 +272,6 @@ private Long dateTimeAsMillis(int columnIndex) throws SQLException {
                 // the cursor can return an Integer if the date-since-epoch is small enough, XContentParser (Jackson) will
                 // return the "smallest" data type for numbers when parsing
                 // TODO: this should probably be handled server side
-                if (val == null) {
-                    return null;
-                }
                 return asDateTimeField(val, JdbcDateUtils::dateTimeAsMillisSinceEpoch, Function.identity());
             }
             if (DATE == type) {
@@ -278,7 +280,7 @@ private Long dateTimeAsMillis(int columnIndex) throws SQLException {
             if (TIME == type) {
                 return timeAsMillisSinceEpoch(val.toString());
             }
-            return val == null ? null : (Long) val;
+            return (Long) val;
         } catch (ClassCastException cce) {
             throw new SQLException(
                     format(Locale.ROOT, "Unable to convert value [%.128s] of type [%s] to a Long", val, type.getName()), cce);

x-pack/plugin/sql/qa/src/main/java/org/elasticsearch/xpack/sql/qa/jdbc/ResultSetTestCase.java

@@ -1275,6 +1275,54 @@ public void testValidGetObjectCalls() throws Exception {
             assertTrue(results.getObject("test_boolean") instanceof Boolean);
         });
     }
+    
+    public void testGettingNullValues() throws Exception {
+        String query = "SELECT CAST(NULL AS BOOLEAN) b, CAST(NULL AS TINYINT) t, CAST(NULL AS SMALLINT) s, CAST(NULL AS INTEGER) i,"
+                + "CAST(NULL AS BIGINT) bi, CAST(NULL AS DOUBLE) d, CAST(NULL AS REAL) r, CAST(NULL AS FLOAT) f, CAST(NULL AS VARCHAR) v,"
+                + "CAST(NULL AS DATE) dt, CAST(NULL AS TIME) tm, CAST(NULL AS TIMESTAMP) ts";
+        doWithQuery(query, (results) -> {
+            results.next();
+            
+            assertNull(results.getObject("b"));
+            assertFalse(results.getBoolean("b"));
+            
+            assertNull(results.getObject("t"));
+            assertEquals(0, results.getByte("t"));
+            
+            assertNull(results.getObject("s"));
+            assertEquals(0, results.getShort("s"));
+            
+            assertNull(results.getObject("i"));
+            assertEquals(0, results.getInt("i"));
+            
+            assertNull(results.getObject("bi"));
+            assertEquals(0, results.getLong("bi"));
+            
+            assertNull(results.getObject("d"));
+            assertEquals(0.0d, results.getDouble("d"), 0d);
+            
+            assertNull(results.getObject("r"));
+            assertEquals(0.0f, results.getFloat("r"), 0f);
+            
+            assertNull(results.getObject("f"));
+            assertEquals(0.0f, results.getFloat("f"), 0f);
+            
+            assertNull(results.getObject("v"));
+            assertNull(results.getString("v"));
+            
+            assertNull(results.getObject("dt"));
+            assertNull(results.getDate("dt"));
+            assertNull(results.getDate("dt", randomCalendar()));
+            
+            assertNull(results.getObject("tm"));
+            assertNull(results.getTime("tm"));
+            assertNull(results.getTime("tm", randomCalendar()));
+            
+            assertNull(results.getObject("ts"));
+            assertNull(results.getTimestamp("ts"));
+            assertNull(results.getTimestamp("ts", randomCalendar()));
+        });
+    }
 
     /*
      * Checks StackOverflowError fix for https://github.com/elastic/elasticsearch/pull/31735
@@ -1841,4 +1889,8 @@ private String asDateString(long millis) {
     private ZoneId getZoneFromOffset(Long randomLongDate) {
         return ZoneId.of(ZoneId.of(timeZoneId).getRules().getOffset(Instant.ofEpochMilli(randomLongDate)).toString());
     }
+    
+    private Calendar randomCalendar() {
+        return Calendar.getInstance(randomTimeZone(), Locale.ROOT);
+    }
 }