[SPARK-33042][SQL][TEST] Add a test case to ensure changes to spark.sql.optimizer.maxIterations take effect at runtime

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/OptimizerSuite.scala

@@ -0,0 +1,74 @@
+/*
+ * 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.optimizer
+
+import org.apache.spark.sql.catalyst.dsl.plans._
+import org.apache.spark.sql.catalyst.errors.TreeNodeException
+import org.apache.spark.sql.catalyst.expressions.{Alias, IntegerLiteral, Literal}
+import org.apache.spark.sql.catalyst.plans.PlanTest
+import org.apache.spark.sql.catalyst.plans.logical.{LogicalPlan, OneRowRelation, Project}
+import org.apache.spark.sql.catalyst.rules.Rule
+import org.apache.spark.sql.internal.SQLConf
+
+/**
+ * A dummy optimizer rule for testing that decrements integer literals until 0.
+ */
+object DecrementLiterals extends Rule[LogicalPlan] {
+  def apply(plan: LogicalPlan): LogicalPlan = plan transformExpressions {
+    case IntegerLiteral(i) if i > 0 => Literal(i - 1)
+  }
+}
+
+class OptimizerSuite extends PlanTest {
+  test("Optimizer exceeds max iterations") {
+    val iterations = 5
+    val maxIterationsNotEnough = 3
+    val maxIterationsEnough = 10
+    val analyzed = Project(Alias(Literal(iterations), "attr")() :: Nil, OneRowRelation()).analyze
+
+    withSQLConf(SQLConf.OPTIMIZER_MAX_ITERATIONS.key -> maxIterationsNotEnough.toString) {
+      val optimizer = new SimpleTestOptimizer() {
+        override def defaultBatches: Seq[Batch] =
+          Batch("test", fixedPoint,
+            DecrementLiterals) :: Nil
+      }
+
+      val message1 = intercept[TreeNodeException[LogicalPlan]] {
+        optimizer.execute(analyzed)
+      }.getMessage
+      assert(message1.startsWith(s"Max iterations ($maxIterationsNotEnough) reached for batch " +
+        s"test, please set '${SQLConf.OPTIMIZER_MAX_ITERATIONS.key}' to a larger value."))
+
+      withSQLConf(SQLConf.OPTIMIZER_MAX_ITERATIONS.key -> maxIterationsEnough.toString) {
+        try {
+          optimizer.execute(analyzed)
+        } catch {
+          case ex: TreeNodeException[LogicalPlan]
+            if ex.getMessage.contains(SQLConf.OPTIMIZER_MAX_ITERATIONS.key) =>
+              fail("optimizer.execute should not reach max iterations.")
+        }
+      }
+
+      val message2 = intercept[TreeNodeException[LogicalPlan]] {
+        optimizer.execute(analyzed)
+      }.getMessage
+      assert(message2.startsWith(s"Max iterations ($maxIterationsNotEnough) reached for batch " +
+        s"test, please set '${SQLConf.OPTIMIZER_MAX_ITERATIONS.key}' to a larger value."))
+    }
+  }
+}