Merge pull request #2276 from ClickHouse/issue-2218

[jdbc-v2] Fix issue #2218 Broken Result with Nullable(FixedString(N))

Author: Paultagoras

client-v2/src/main/java/com/clickhouse/client/api/data_formats/internal/BinaryStreamReader.java

@@ -103,7 +103,6 @@ public <T> T readValue(ClickHouseColumn column, Class<?> typeHint) throws IOExce
 
         ClickHouseColumn actualColumn = column.getDataType() == ClickHouseDataType.Dynamic ? readDynamicData() : column;
         ClickHouseDataType dataType = actualColumn.getDataType();
-        int estimatedLen = actualColumn.getEstimatedLength();
         int precision = actualColumn.getPrecision();
         int scale = actualColumn.getScale();
         TimeZone timezone = actualColumn.getTimeZoneOrDefault(timeZone);
@@ -112,10 +111,10 @@ public <T> T readValue(ClickHouseColumn column, Class<?> typeHint) throws IOExce
             switch (dataType) {
                 // Primitives
                 case FixedString: {
-                    byte[] bytes = estimatedLen > STRING_BUFF.length ?
-                            new byte[estimatedLen] : STRING_BUFF;
-                    readNBytes(input, bytes, 0, estimatedLen);
-                    return (T) new String(bytes, 0, estimatedLen, StandardCharsets.UTF_8);
+                    byte[] bytes = precision > STRING_BUFF.length ?
+                            new byte[precision] : STRING_BUFF;
+                    readNBytes(input, bytes, 0, precision);
+                    return (T) new String(bytes, 0, precision, StandardCharsets.UTF_8);
                 }
                 case String: {
                     return (T) readString();

jdbc-v2/src/test/java/com/clickhouse/jdbc/StatementTest.java

@@ -573,7 +573,8 @@ public void testSwitchDatabase() throws Exception {
             }
         }
     }
-
+  
+  
     @Test(groups = { "integration" })
     public void testNewLineSQLParsing() throws Exception {
         try (Connection conn = getJdbcConnection()) {
@@ -637,4 +638,37 @@ public void testNewLineSQLParsing() throws Exception {
             }
         }
     }
+
+    
+    @Test(groups = { "integration" })
+    public void testNullableFixedStringType() throws Exception {
+        try (Connection conn = getJdbcConnection()) {
+            String sqlCreate = "CREATE TABLE `data_types` (`f1` FixedString(4),`f2` LowCardinality(FixedString(4)), `f3` Nullable(FixedString(4)), `f4` LowCardinality(Nullable(FixedString(4))) ) ENGINE Memory;";
+            try (Statement stmt = conn.createStatement()) {
+                int r = stmt.executeUpdate(sqlCreate);
+                assertEquals(r, 0);
+            }
+            try(Statement stmt = conn.createStatement()) {
+                String sqlInsert = "INSERT INTO `data_types` VALUES ('val1', 'val2', 'val3', 'val4')";
+                int r = stmt.executeUpdate(sqlInsert);
+                assertEquals(r, 1);
+            }
+            try(Statement stmt = conn.createStatement()) {
+                String sqlSelect = "SELECT * FROM `data_types`";
+                ResultSet rs = stmt.executeQuery(sqlSelect);
+                assertTrue(rs.next());
+                assertEquals(rs.getString(1), "val1");
+                assertEquals(rs.getString(2), "val2");
+                assertEquals(rs.getString(3), "val3");
+                assertEquals(rs.getString(4), "val4");
+                assertFalse(rs.next());
+            }
+            try(Statement stmt = conn.createStatement()) {
+                String sqlSelect = "SELECT f4 FROM `data_types`";
+                ResultSet rs = stmt.executeQuery(sqlSelect);
+                assertTrue(rs.next());
+                assertEquals(rs.getString(1), "val4");
+            }
+        }
+    }
 }