Address comments

Signed-off-by: Chong Gao <res_life@163.com>

Author: Chong Gao

sql-plugin/src/main/scala/org/apache/spark/sql/rapids/GpuShuffleEnv.scala

@@ -108,20 +108,21 @@ object GpuShuffleEnv extends Logging {
     conf.getBoolean("spark.authenticate", false)
   }
 
+  // Returns true if row-based checksum is enabled, which is not supported
+  // by the RAPIDS Shuffle Manager
+  def isRowBasedChecksumEnabled: Boolean = {
+    val conf = SparkEnv.get.conf
+    // Row-based checksum feature was added in Spark 4.1.x (SPARK-51756).
+    // Fully supporting this feature would require kernel development to compute
+    // checksums on the GPU side.
+    conf.getBoolean("spark.shuffle.checksum.enabled", false)
+  }
+
   //
   // The actual instantiation of the RAPIDS Shuffle Manager is lazy, and
   // this forces the initialization when we know we are ready in the driver and executor.
   //
   def initShuffleManager(): Unit = {
-    val conf = SparkEnv.get.conf
-    // Row-based checksum feature was added in Spark 4.1.x (SPARK-51756).
-    // Fully supporting this feature would require kernel development to compute
-    // checksums on the GPU side.
-    if (conf.getBoolean("spark.shuffle.checksum.enabled", false)) {
-      throw new IllegalStateException(
-        "RAPIDS Shuffle Manager does not support spark.shuffle.checksum.enabled. " +
-        "Please set spark.shuffle.checksum.enabled to false or disable the RAPIDS Shuffle Manager.")
-    }
     val shuffleManager = SparkEnv.get.shuffleManager
     if (ShuffleManagerShimUtils.eagerlyInitialized) {
       // skip deferred init

sql-plugin/src/main/scala/org/apache/spark/sql/rapids/RapidsShuffleInternalManagerBase.scala

@@ -1623,6 +1623,10 @@ class RapidsShuffleInternalManagerBase(conf: SparkConf, val isDriver: Boolean)
       if (GpuShuffleEnv.isSparkAuthenticateEnabled) {
         fallThroughReasons += "Spark authentication is enabled"
       }
+      if (GpuShuffleEnv.isRowBasedChecksumEnabled) {
+        fallThroughReasons += "Detected spark.shuffle.checksum.enabled=true. " +
+          "This feature is supported in Spark 4.1+, but is not yet supported by Spark-Rapids."
+      }
     }
     if (rapidsConf.isSqlExplainOnlyEnabled) {
       fallThroughReasons += "Plugin is in explain only mode"