[SPARK-9448][SQL] GenerateUnsafeProjection should not share expressions across instances.

Author: rxin

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/codegen/GenerateUnsafeProjection.scala

@@ -256,18 +256,18 @@ object GenerateUnsafeProjection extends CodeGenerator[Seq[Expression], UnsafePro
     eval.code = createCode(ctx, eval, expressions)
 
     val code = s"""
-      private $exprType[] expressions;
-
-      public Object generate($exprType[] expr) {
-        this.expressions = expr;
-        return new SpecificProjection();
+      public Object generate($exprType[] exprs) {
+        return new SpecificProjection(exprs);
       }
 
       class SpecificProjection extends ${classOf[UnsafeProjection].getName} {
 
+        private $exprType[] expressions;
+
         ${declareMutableStates(ctx)}
 
-        public SpecificProjection() {
+        public SpecificProjection($exprType[] expressions) {
+          this.expressions = expressions;
           ${initMutableStates(ctx)}
         }
 

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/codegen/CodegenExpressionCachingSuite.scala

@@ -0,0 +1,90 @@
+/*
+ * 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.spark.sql.catalyst.expressions.codegen
+
+import org.apache.spark.SparkFunSuite
+import org.apache.spark.sql.catalyst.InternalRow
+import org.apache.spark.sql.catalyst.expressions.{UnsafeProjection, LeafExpression}
+import org.apache.spark.sql.types.{BooleanType, DataType}
+
+/**
+ * A test suite that makes sure code generation handles expression internally states correctly.
+ */
+class CodegenExpressionCachingSuite extends SparkFunSuite {
+
+  test("GenerateUnsafeProjection") {
+    val expr1 = MutableExpression()
+    val instance1 = UnsafeProjection.create(Seq(expr1))
+    assert(instance1.apply(null).getBoolean(0) === false)
+
+    val expr2 = MutableExpression()
+    expr2.mutableState = true
+    val instance2 = UnsafeProjection.create(Seq(expr2))
+    assert(instance1.apply(null).getBoolean(0) === false)
+    assert(instance2.apply(null).getBoolean(0) === true)
+  }
+
+  test("GenerateProjection") {
+    val expr1 = MutableExpression()
+    val instance1 = GenerateProjection.generate(Seq(expr1))
+    assert(instance1.apply(null).getBoolean(0) === false)
+
+    val expr2 = MutableExpression()
+    expr2.mutableState = true
+    val instance2 = GenerateProjection.generate(Seq(expr2))
+    assert(instance1.apply(null).getBoolean(0) === false)
+    assert(instance2.apply(null).getBoolean(0) === true)
+  }
+
+  test("GenerateMutableProjection") {
+    val expr1 = MutableExpression()
+    val instance1 = GenerateMutableProjection.generate(Seq(expr1))()
+    assert(instance1.apply(null).getBoolean(0) === false)
+
+    val expr2 = MutableExpression()
+    expr2.mutableState = true
+    val instance2 = GenerateMutableProjection.generate(Seq(expr2))()
+    assert(instance1.apply(null).getBoolean(0) === false)
+    assert(instance2.apply(null).getBoolean(0) === true)
+  }
+
+  test("GeneratePredicate") {
+    val expr1 = MutableExpression()
+    val instance1 = GeneratePredicate.generate(expr1)
+    assert(instance1.apply(null) === false)
+
+    val expr2 = MutableExpression()
+    expr2.mutableState = true
+    val instance2 = GeneratePredicate.generate(expr2)
+    assert(instance1.apply(null) === false)
+    assert(instance2.apply(null) === true)
+  }
+
+}
+
+
+/**
+ * An expression with mutable state so we can change it freely in our test suite.
+ */
+case class MutableExpression() extends LeafExpression with CodegenFallback {
+  var mutableState: Boolean = false
+  override def eval(input: InternalRow): Any = mutableState
+
+  override def nullable: Boolean = false
+  override def dataType: DataType = BooleanType
+}