[fix](fe) Key column varchar length change should't light schema change

fe/fe-core/src/main/java/org/apache/doris/alter/SchemaChangeHandler.java

@@ -588,7 +588,13 @@ private boolean processModifyColumn(ModifyColumnClause alterClause, OlapTable ol
                     if (columnPos == null && col.getDataType() == PrimitiveType.VARCHAR
                             && modColumn.getDataType() == PrimitiveType.VARCHAR) {
                         col.checkSchemaChangeAllowed(modColumn);
-                        lightSchemaChange = olapTable.getEnableLightSchemaChange();
+                        // If col and modColumn is not key, it allow light schema change,
+                        // of course, olapTable has been enable light schema change
+                        if (modColumn.isKey() || col.isKey()) {
+                            lightSchemaChange = false;
+                        } else {
+                            lightSchemaChange = olapTable.getEnableLightSchemaChange();
+                        }
                     }
                     if (col.isClusterKey()) {
                         throw new DdlException("Can not modify cluster key column: " + col.getName());

fe/fe-core/src/main/java/org/apache/doris/datasource/InternalCatalog.java

@@ -1475,7 +1475,7 @@ public void addPartition(Database db, String tableName, AddPartitionClause addPa
                     if (!hashDistributionInfo.sameDistributionColumns((HashDistributionInfo) defaultDistributionInfo)) {
                         throw new DdlException("Cannot assign hash distribution with different distribution cols. "
                                 + "new is: " + hashDistributionInfo.getDistributionColumns() + " default is: "
-                                + ((HashDistributionInfo) distributionInfo).getDistributionColumns());
+                                + ((HashDistributionInfo) defaultDistributionInfo).getDistributionColumns());
                     }
                 } else if (distributionInfo.getType() == DistributionInfoType.RANDOM) {
                     RandomDistributionInfo randomDistributionInfo = (RandomDistributionInfo) distributionInfo;

regression-test/suites/schema_change_p0/test_varchar_schema_change_with_distribution.groovy

@@ -0,0 +1,52 @@
+// 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.
+
+suite ("test_varchar_schema_change_with_distribution") {
+    def tableName = "test_varchar_schema_change_with_distribution"
+    sql """ DROP TABLE IF EXISTS ${tableName} FORCE;"""
+
+    sql """
+        CREATE TABLE ${tableName}
+        (
+            dt datetime NOT NULL COMMENT '分区日期',
+            citycode SMALLINT,
+            watts_range VARCHAR(20),
+            pv BIGINT SUM DEFAULT '0'
+        )
+        AGGREGATE KEY(dt, citycode, watts_range)
+        PARTITION BY RANGE(dt)()
+        DISTRIBUTED BY HASH(dt, watts_range) BUCKETS 1
+        PROPERTIES (
+            "dynamic_partition.enable"="true",
+            "dynamic_partition.end"="3",
+            "dynamic_partition.buckets"="1",
+            "dynamic_partition.start"="-3",
+            "dynamic_partition.prefix"="p",
+            "dynamic_partition.time_unit"="HOUR",
+            "dynamic_partition.create_history_partition"="true",
+            "dynamic_partition.replication_allocation" = "tag.location.default: 1"
+        );
+    """
+
+    test {
+        sql """ alter table ${tableName} modify column watts_range varchar(30) """
+        exception "Can not modify distribution column"
+    }
+
+    sql """ DROP TABLE IF EXISTS ${tableName} FORCE;"""
+
+}