[fix](index)Add duplicated indexes check in add index (#46155)

Issue Number: close #46153

Problem Summary:

```
create table t(a int, b int, c tinyint);
alter table t add index idx1(a), add index idx2(a);
alter table t add index idx1(a), add index idx1(a);
```
Both create index sql should fail.

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

@@ -2704,7 +2704,7 @@ private void cancelIndexJob(CancelAlterTableStmt cancelAlterTableStmt) throws Dd
 
     /**
      * Returns true if the index already exists, there is no need to create the job to add the index.
-     * Otherwise return false, there is need to create a job to add the index.
+     * Otherwise, return false, there is need to create a job to add the index.
      */
     private boolean processAddIndex(CreateIndexClause alterClause, OlapTable olapTable, List<Index> newIndexes)
             throws UserException {
@@ -2718,23 +2718,11 @@ private boolean processAddIndex(CreateIndexClause alterClause, OlapTable olapTab
         Set<String> newColset = Sets.newTreeSet(String.CASE_INSENSITIVE_ORDER);
         newColset.addAll(indexDef.getColumns());
         Set<Long> existedIndexIdSet = Sets.newHashSet();
-        for (Index existedIdx : existedIndexes) {
-            if (existedIdx.getIndexName().equalsIgnoreCase(indexDef.getIndexName())) {
-                if (indexDef.isSetIfNotExists()) {
-                    LOG.info("create index[{}] which already exists on table[{}]", indexDef.getIndexName(),
-                            olapTable.getName());
-                    return true;
-                }
-                throw new DdlException("index `" + indexDef.getIndexName() + "` already exist.");
-            }
-            Set<String> existedIdxColSet = Sets.newTreeSet(String.CASE_INSENSITIVE_ORDER);
-            existedIdxColSet.addAll(existedIdx.getColumns());
-            if (existedIdx.getIndexType() == indexDef.getIndexType() && newColset.equals(existedIdxColSet)) {
-                throw new DdlException(
-                        indexDef.getIndexType() + " index for columns (" + String.join(",", indexDef.getColumns())
-                                + " ) already exist.");
-            }
-            existedIndexIdSet.add(existedIdx.getIndexId());
+        if (checkDuplicateIndexes(existedIndexes, indexDef, newColset, existedIndexIdSet, olapTable)) {
+            return true;
+        }
+        if (checkDuplicateIndexes(newIndexes, indexDef, newColset, existedIndexIdSet, olapTable)) {
+            return true;
         }
 
         // The restored olap table may not reset the index id, which comes from the upstream,
@@ -2770,6 +2758,29 @@ private boolean processAddIndex(CreateIndexClause alterClause, OlapTable olapTab
         return false;
     }
 
+    private boolean checkDuplicateIndexes(List<Index> indexes, IndexDef indexDef, Set<String> newColset,
+                                          Set<Long> existedIndexIdSet, OlapTable olapTable) throws DdlException {
+        for (Index index : indexes) {
+            if (index.getIndexName().equalsIgnoreCase(indexDef.getIndexName())) {
+                if (indexDef.isSetIfNotExists()) {
+                    LOG.info("create index[{}] which already exists on table[{}]", indexDef.getIndexName(),
+                            olapTable.getName());
+                    return true;
+                }
+                throw new DdlException("index `" + indexDef.getIndexName() + "` already exist.");
+            }
+            Set<String> existedIdxColSet = Sets.newTreeSet(String.CASE_INSENSITIVE_ORDER);
+            existedIdxColSet.addAll(index.getColumns());
+            if (index.getIndexType() == indexDef.getIndexType() && newColset.equals(existedIdxColSet)) {
+                throw new DdlException(
+                        indexDef.getIndexType() + " index for columns (" + String.join(",", indexDef.getColumns())
+                                + ") already exist.");
+            }
+            existedIndexIdSet.add(index.getIndexId());
+        }
+        return false;
+    }
+
     /**
      * Returns true if the index does not exist, there is no need to create the job to drop the index.
      * Otherwise return false, there is need to create a job to drop the index.

fe/fe-core/src/test/java/org/apache/doris/alter/SchemaChangeHandlerTest.java

@@ -556,4 +556,40 @@ public void testDupAddOrDropInvertedIndex() throws Exception {
             tbl.readUnlock();
         }
     }
+
+    @Test
+    public void testAddDuplicateInvertedIndexException() throws Exception {
+
+        LOG.info("dbName: {}", Env.getCurrentInternalCatalog().getDbNames());
+
+        Database db = Env.getCurrentInternalCatalog().getDbOrMetaException("test");
+        OlapTable tbl = (OlapTable) db.getTableOrMetaException("sc_dup", Table.TableType.OLAP);
+        tbl.readLock();
+        try {
+            Assertions.assertNotNull(tbl);
+            Assertions.assertEquals("Doris", tbl.getEngine());
+            Assertions.assertEquals(0, tbl.getIndexes().size());
+        } finally {
+            tbl.readUnlock();
+        }
+
+        String addInvertedIndexStmtStr = "alter table test.sc_dup add index idx_error_msg(error_msg), "
+                + "add index idx_error_msg1(error_msg)";
+        AlterTableStmt addInvertedIndexStmt = (AlterTableStmt) parseAndAnalyzeStmt(addInvertedIndexStmtStr);
+        try {
+            Env.getCurrentEnv().getAlterInstance().processAlterTable(addInvertedIndexStmt);
+        } catch (Exception e) {
+            // Verify the error message contains relevant info
+            Assertions.assertTrue(e.getMessage().contains("INVERTED index for columns (error_msg) already exist"));
+        }
+        addInvertedIndexStmtStr = "alter table test.sc_dup add index idx_error_msg(error_msg), "
+                + "add index idx_error_msg(error_msg)";
+        addInvertedIndexStmt = (AlterTableStmt) parseAndAnalyzeStmt(addInvertedIndexStmtStr);
+        try {
+            Env.getCurrentEnv().getAlterInstance().processAlterTable(addInvertedIndexStmt);
+        } catch (Exception e) {
+            // Verify the error message contains relevant info
+            Assertions.assertTrue(e.getMessage().contains("index `idx_error_msg` already exist."));
+        }
+    }
 }