[UDF] Fix bug that UDF can't handle constant null value (#2914)

This CL modify the `evalExpr()` of ExpressionFunctions, so that it won't change the
`FunctionCallExpr` to `NullLiteral` when there is null parameter in UDF. Which will fix the
problem described in ISSUE: #2913

fe/src/test/java/org/apache/doris/alter/BatchRollupJobTest.java

@@ -40,8 +40,6 @@ public class BatchRollupJobTest {
 
     private static String runningDir = "fe/mocked/BatchRollupJobTest/" + UUID.randomUUID().toString() + "/";
 
-    private static ConnectContext ctx = UtFrameUtils.createDefaultCtx();
-
     @BeforeClass
     public static void setup() throws Exception {
         UtFrameUtils.createMinDorisCluster(runningDir);
@@ -49,7 +47,7 @@ public class BatchRollupJobTest {
 
     @Test
     public void test() throws Exception {
-        System.out.println("xxx");
+        ConnectContext ctx = UtFrameUtils.createDefaultCtx();
         // create database db1
         String createDbStmtStr = "create database db1;";
         CreateDbStmt createDbStmt = (CreateDbStmt) UtFrameUtils.parseAndAnalyzeStmt(createDbStmtStr, ctx);

fe/src/test/java/org/apache/doris/catalog/CreateFunctionTest.java

@@ -0,0 +1,105 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package org.apache.doris.catalog;
+
+import org.apache.doris.analysis.CreateDbStmt;
+import org.apache.doris.analysis.CreateFunctionStmt;
+import org.apache.doris.analysis.Expr;
+import org.apache.doris.analysis.FunctionCallExpr;
+import org.apache.doris.common.jmockit.Deencapsulation;
+import org.apache.doris.planner.PlanFragment;
+import org.apache.doris.planner.Planner;
+import org.apache.doris.planner.UnionNode;
+import org.apache.doris.qe.ConnectContext;
+import org.apache.doris.qe.QueryState;
+import org.apache.doris.qe.StmtExecutor;
+import org.apache.doris.utframe.UtFrameUtils;
+
+import org.junit.AfterClass;
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.io.File;
+import java.util.List;
+import java.util.UUID;
+
+/*
+ * Author: Chenmingyu
+ * Date: Feb 16, 2020
+ */
+
+public class CreateFunctionTest {
+
+    private static String runningDir = "fe/mocked/CreateFunctionTest/" + UUID.randomUUID().toString() + "/";
+
+    @BeforeClass
+    public static void setup() throws Exception {
+        UtFrameUtils.createMinDorisCluster(runningDir);
+    }
+
+    @AfterClass
+    public static void teardown() {
+        File file = new File("fe/mocked/CreateFunctionTest/");
+        file.delete();
+    }
+
+    @Test
+    public void test() throws Exception {
+        ConnectContext ctx = UtFrameUtils.createDefaultCtx();
+
+        // create database db1
+        String createDbStmtStr = "create database db1;";
+        CreateDbStmt createDbStmt = (CreateDbStmt) UtFrameUtils.parseAndAnalyzeStmt(createDbStmtStr, ctx);
+        Catalog.getCurrentCatalog().createDb(createDbStmt);
+        System.out.println(Catalog.getCurrentCatalog().getDbNames());
+
+        Database db = Catalog.getCurrentCatalog().getDb("default_cluster:db1");
+        Assert.assertNotNull(db);
+
+        String createFuncStr = "create function db1.my_add(VARCHAR(1024)) RETURNS BOOLEAN properties\n" +
+                "(\n" +
+                "\"symbol\" =  \"_ZN9doris_udf6AddUdfEPNS_15FunctionContextERKNS_9StringValE\",\n" +
+                "\"prepare_fn\" = \"_ZN9doris_udf13AddUdfPrepareEPNS_15FunctionContextENS0_18FunctionStateScopeE\",\n" +
+                "\"close_fn\" = \"_ZN9doris_udf11AddUdfCloseEPNS_15FunctionContextENS0_18FunctionStateScopeE\",\n" +
+                "\"object_file\" = \"http://nmg01-inf-dorishb00.nmg01.baidu.com:8456/libcmy_udf.so\"\n" +
+                ");";
+        
+        CreateFunctionStmt createFunctionStmt = (CreateFunctionStmt) UtFrameUtils.parseAndAnalyzeStmt(createFuncStr, ctx);
+        Catalog.getCurrentCatalog().createFunction(createFunctionStmt);
+
+        List<Function> functions = db.getFunctions();
+        Assert.assertEquals(1, functions.size());
+        Assert.assertTrue(functions.get(0).isUdf());
+
+        String queryStr = "select db1.my_add(null)";
+        ctx.getState().reset();
+        StmtExecutor stmtExecutor = new StmtExecutor(ctx, queryStr);
+        stmtExecutor.execute();
+        Assert.assertNotEquals(QueryState.MysqlStateType.ERR, ctx.getState().getStateType());
+        Planner planner = stmtExecutor.planner();
+        Assert.assertEquals(1, planner.getFragments().size());
+        PlanFragment fragment = planner.getFragments().get(0);
+        Assert.assertTrue(fragment.getPlanRoot() instanceof UnionNode);
+        UnionNode unionNode =  (UnionNode)fragment.getPlanRoot();
+        List<List<Expr>> constExprLists = Deencapsulation.getField(unionNode, "constExprLists_");
+        Assert.assertEquals(1, constExprLists.size());
+        Assert.assertEquals(1, constExprLists.get(0).size());
+        Assert.assertTrue(constExprLists.get(0).get(0) instanceof FunctionCallExpr);
+    }
+}

fe/src/test/java/org/apache/doris/utframe/UtFrameUtils.java

@@ -42,6 +42,7 @@ import com.google.common.collect.Maps;
 
 import java.io.IOException;
 import java.io.StringReader;
+import java.nio.channels.SocketChannel;
 import java.util.List;
 import java.util.Map;
 import java.util.Random;
@@ -49,8 +50,9 @@ import java.util.Random;
 public class UtFrameUtils {
 
     // Help to create a mocked ConnectContext.
-    public static ConnectContext createDefaultCtx() {
-        ConnectContext ctx = new ConnectContext();
+    public static ConnectContext createDefaultCtx() throws IOException {
+        SocketChannel channel = SocketChannel.open();
+        ConnectContext ctx = new ConnectContext(channel);
         ctx.setCluster(SystemInfoService.DEFAULT_CLUSTER);
         ctx.setCurrentUserIdentity(UserIdentity.ROOT);
         ctx.setQualifiedUser(PaloAuth.ROOT_USER);