[fix](Nereids) eliminate union should execute before limit push down

other wise:

push limit through union could generate plan:

```
limit
+-- union
    |-- limit
    |   +-- empty relation
    +-- limit
        +-- project
```

and then eliminate union will generate plan:

```
+-- limit
    +-  project
        +-- limit
            +-- project
```

it could not be processed by tranlator correctly

fe/fe-core/src/main/java/org/apache/doris/nereids/jobs/executor/Rewriter.java

@@ -364,32 +364,6 @@ public class Rewriter extends AbstractBatchJobExecutor {
                         topDown(new EliminateGroupByKey()),
                         topDown(new PushDownAggThroughJoinOnPkFk())
                 ),
-
-                topic("Limit optimization",
-                        // TODO: the logical plan should not contains any phase information,
-                        //       we should refactor like AggregateStrategies, e.g. LimitStrategies,
-                        //       generate one PhysicalLimit if current distribution is gather or two
-                        //       PhysicalLimits with gather exchange
-                        topDown(new LimitSortToTopN()),
-                        topDown(new LimitAggToTopNAgg()),
-                        topDown(new MergeTopNs()),
-                        topDown(new SplitLimit()),
-                        topDown(
-                                new PushDownLimit(),
-                                new PushDownLimitDistinctThroughJoin(),
-                                new PushDownLimitDistinctThroughUnion(),
-                                new PushDownTopNDistinctThroughJoin(),
-                                new PushDownTopNDistinctThroughUnion(),
-                                new PushDownTopNThroughJoin(),
-                                new PushDownTopNThroughWindow(),
-                                new PushDownTopNThroughUnion()
-                        ),
-                        topDown(new CreatePartitionTopNFromWindow()),
-                        topDown(
-                                new PullUpProjectUnderTopN(),
-                                new PullUpProjectUnderLimit()
-                        )
-                ),
                 // TODO: these rules should be implementation rules, and generate alternative physical plans.
                 topic("Table/Physical optimization",
                         topDown(
@@ -425,9 +399,55 @@ public class Rewriter extends AbstractBatchJobExecutor {
                         bottomUp(new EliminateEmptyRelation())
                 ),
                 topic("agg rewrite",
-                    // these rules should be put after mv optimization to avoid mv matching fail
-                    topDown(new SumLiteralRewrite(),
-                            new MergePercentileToArray())
+                        // these rules should be put after mv optimization to avoid mv matching fail
+                        topDown(new SumLiteralRewrite(),
+                                new MergePercentileToArray())
+                ),
+                // limit push down through union should execute after eliminate union by empty relation.
+                // otherwise will generate illegal plan
+                // think about
+                // limit
+                // +-- union
+                //    |-- empty relation
+                //    +-- project 1
+                //
+                // after PUSH_LIMIT_THROUGH_UNION will generate
+                // limit
+                // +-- union
+                //     |-- limit
+                //     |   +-- empty relation
+                //     +-- limit
+                //         +-- project 1
+                // after ELIMINATE_UNION_BY_EMPTY_RELATION will generate
+                // +-- limit
+                //     +-  project 2
+                //         +-- limit
+                //             +-- project 1
+                // the last plan is illegal because translator will lose info in project 1
+                topic("Limit optimization",
+                        // TODO: the logical plan should not contains any phase information,
+                        //       we should refactor like AggregateStrategies, e.g. LimitStrategies,
+                        //       generate one PhysicalLimit if current distribution is gather or two
+                        //       PhysicalLimits with gather exchange
+                        topDown(new LimitSortToTopN()),
+                        topDown(new LimitAggToTopNAgg()),
+                        topDown(new MergeTopNs()),
+                        topDown(new SplitLimit()),
+                        topDown(
+                                new PushDownLimit(),
+                                new PushDownLimitDistinctThroughJoin(),
+                                new PushDownLimitDistinctThroughUnion(),
+                                new PushDownTopNDistinctThroughJoin(),
+                                new PushDownTopNDistinctThroughUnion(),
+                                new PushDownTopNThroughJoin(),
+                                new PushDownTopNThroughWindow(),
+                                new PushDownTopNThroughUnion()
+                        ),
+                        topDown(new CreatePartitionTopNFromWindow()),
+                        topDown(
+                                new PullUpProjectUnderTopN(),
+                                new PullUpProjectUnderLimit()
+                        )
                 ),
                 topic("Push project and filter on cte consumer to cte producer",
                         topDown(

regression-test/suites/nereids_p0/union/push_limit_with_eliminate_union.groovy

@@ -0,0 +1,21 @@
+// 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("push_limit_with_eliminate_union") {
+    // this should not failed for [INTERNAL_ERROR]VSlotRef  have invalid slot id
+    sql """(select 1 limit 0 union all select count() + 1) limit 1;"""
+}