Au-Miner opened a new pull request, #28246:
URL: https://github.com/apache/flink/pull/28246

   ## What is the purpose of the change
   
   When a `Correlate` has a `Calc` on its right side that adds non-identity 
projections (e.g. `LATERAL (SELECT s * 2 FROM UNNEST(...) AS T(s))`), the 
physical conversion previously dropped those projections, leaving wrong output 
columns. This PR preserves them by wrapping the resulting `Correlate` in a 
`Calc` that re-applies the right-side projections.
   
   ## Brief change log
   
   - `StreamPhysicalCorrelateRule` / `BatchPhysicalCorrelateRule`: split the 
right-side calc into `(scan, projects, condition)`; when projects are 
non-identity, build an inner `*PhysicalCorrelate` with the natural join row 
type and wrap it in a `*PhysicalCalc` whose program is built by the new 
`buildOuterProgram` helper that shifts right-side projections past the left 
field count.
   - `FlinkCalcMergeRule`: add `BATCH_PHYSICAL_INSTANCE` so the new wrapping 
calc can merge with adjacent batch calcs (mirrors the existing 
`STREAM_PHYSICAL_INSTANCE`).
   - `FlinkBatchRuleSets#PHYSICAL_OPT_RULES`: register 
`FlinkCalcMergeRule.BATCH_PHYSICAL_INSTANCE`.
   
   ## Verifying this change
   
   Added `testLateralProjectionFromUnnest` in `UnnestTestBase` (exercised by 
both stream and batch `UnnestTest`) which asserts that the optimized plan 
contains a `Calc(select=[a, *(b0, 2) AS doubled])` over the `Correlate`. Added 
`testCorrelateWithRightSideProjection` in `CorrelateITCase` which runs `LATERAL 
(SELECT CONCAT(v, '_x') FROM TABLE(STRING_SPLIT(c, '|')) AS T(v))` and asserts 
the projected values appear in the sink. Updated `UnnestTest.xml` plans (stream 
+ batch) accordingly.
   
   ## Does this pull request potentially affect one of the following parts:
   
     - Dependencies (does it add or upgrade a dependency): no
     - The public API, i.e., is any changed class annotated with 
`@Public(Evolving)`: no
     - The serializers: no
     - The runtime per-record code paths (performance sensitive): no
     - Anything that affects deployment or recovery: JobManager (and its 
components), Checkpointing, Kubernetes/Yarn, ZooKeeper: no
     - The S3 file system connector: no
   
   ## Documentation
   
     - Does this pull request introduce a new feature? no
     - If yes, how is the feature documented? no
   


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