[fix][refactor] fix bugs and refactor some code by lint (#7871)

1. Fix some `passedByValue` issues.
2. Fix some `dereferenceBeforeCheck` issues.
3. Fix some `uninitMemberVar` issues.
4. Fix some iterator `eraseDereference` issues.
5. Fix compile issue introduced from #7923 #7905 #7848

fe/fe-core/src/main/cup/sql_parser.cup

@@ -2717,7 +2717,7 @@ show_param ::=
     {:
         RESULT = new ShowAlterStmt(type, db, parser.where, orderByClause, limitClause);
     :}
-    | KW_SHOW KW_DATA KW_SKEW KW_FROM base_table_ref:table_ref
+    | KW_DATA KW_SKEW KW_FROM base_table_ref:table_ref
     {:
         RESULT = new ShowDataSkewStmt(table_ref);
     :}

fe/fe-core/src/main/java/org/apache/doris/catalog/Catalog.java

@@ -3933,7 +3933,7 @@ public class Catalog {
                 long totalReplicaNum = 0;
                 for (Map.Entry<String, Long> entry : partitionNameToId.entrySet()) {
                     long indexNum = olapTable.getIndexIdToMeta().size();
-                    long bucketNum = distributionInfo.getBucketNum();
+                    long bucketNum = defaultDistributionInfo.getBucketNum();
                     long replicaNum = partitionInfo.getReplicaAllocation(entry.getValue()).getTotalReplicaNum();
                     totalReplicaNum += indexNum * bucketNum * replicaNum;
                 }

fe/fe-core/src/main/java/org/apache/doris/httpv2/rest/TableSchemaAction.java

@@ -40,6 +40,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

fe/fe-core/src/main/java/org/apache/doris/mysql/nio/NConnectContext.java

@@ -18,6 +18,7 @@ package org.apache.doris.mysql.nio;
 
 import org.apache.doris.qe.ConnectContext;
 import org.apache.doris.qe.ConnectProcessor;
+
 import org.xnio.StreamConnection;
 
 import java.io.IOException;
@@ -59,4 +60,10 @@ public class NConnectContext extends ConnectContext {
     public void stopAcceptQuery() throws IOException {
         mysqlChannel.stopAcceptQuery();
     }
+
+    @Override
+    public String toString() {
+        return "[remote ip: " + mysqlChannel.getRemoteIp() + "]";
+    }
 }
+

fe/fe-core/src/test/java/org/apache/doris/catalog/CatalogOperationTest.java

@@ -133,6 +133,7 @@ public class CatalogOperationTest {
             Assert.assertEquals(AlterJobV2.JobState.FINISHED, alterJobV2.getJobState());
         }
 
+        Thread.sleep(1000);
         renameTblStmt = "alter table test.newNewTest rename r1";
         alterTableStmt = (AlterTableStmt)UtFrameUtils.parseAndAnalyzeStmt(renameTblStmt, connectContext);
         try {