johanl-db commented on code in PR #55508:
URL: https://github.com/apache/spark/pull/55508#discussion_r3131260767


##########
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/ResolveChangelogTable.scala:
##########
@@ -0,0 +1,315 @@
+/*
+ * 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.
+ */
+
+package org.apache.spark.sql.catalyst.analysis
+
+import org.apache.spark.sql.catalyst.expressions._
+import org.apache.spark.sql.catalyst.expressions.aggregate.{Count, Max, Min}
+import org.apache.spark.sql.catalyst.plans.logical._
+import org.apache.spark.sql.catalyst.rules.Rule
+import org.apache.spark.sql.catalyst.streaming.StreamingRelationV2
+import org.apache.spark.sql.catalyst.trees.TreeNodeTag
+import org.apache.spark.sql.connector.catalog.{Changelog, ChangelogInfo}
+import org.apache.spark.sql.errors.QueryCompilationErrors
+import org.apache.spark.sql.execution.datasources.v2.{ChangelogTable, 
DataSourceV2Relation}
+import org.apache.spark.sql.types.{IntegerType, StringType}
+
+/**
+ * Post-processes a resolved [[ChangelogTable]] read to apply CDC option 
semantics
+ * (carry-over removal, update detection) and to enforce supported option 
combinations.
+ *
+ * Fires after [[ResolveRelations]] has wrapped the connector's [[Changelog]] 
in a
+ * [[ChangelogTable]]. Both batch ([[DataSourceV2Relation]]) and streaming
+ * ([[StreamingRelationV2]]) reads are handled:
+ *   - Batch: the requested post-processing passes are injected as logical 
operators on top
+ *     of the relation. Carry-over removal and update detection are fused into 
a single
+ *     pass over a (rowId, _commit_version)-partitioned Window: the Filter 
drops CoW
+ *     carry-over pairs (same rowVersion on both sides) and the subsequent 
Project relabels
+ *     real delete+insert pairs as update_preimage / update_postimage.
+ *   - Streaming: post-processing is not yet supported. If the requested 
options would
+ *     require any post-processing, the rule throws an explicit 
[[AnalysisException]] to
+ *     prevent silent wrong results. Streams that don't require 
post-processing pass
+ *     through unchanged.
+ *
+ * Net change computation (`deduplicationMode = netChanges`) is not yet 
implemented and
+ * is rejected up-front for both batch and streaming.
+ */
+object ResolveChangelogTable extends Rule[LogicalPlan] {
+
+  private val CHANGELOG_TRANSFORMED_TAG =
+    TreeNodeTag[Boolean]("changelog_transformed")
+
+  private object HelperColumn {
+    final val DelCnt = "_del_cnt"
+    final val InsCnt = "_ins_cnt"
+    final val MinRv = "_min_rv"
+    final val MaxRv = "_max_rv"
+
+    val all: Set[String] = Set(DelCnt, InsCnt, MinRv, MaxRv)
+  }
+
+  override def apply(plan: LogicalPlan): LogicalPlan = {
+    if (isAlreadyTransformed(plan)) return plan
+    var updatedPlan = plan
+    updatedPlan = plan.resolveOperatorsUp {
+      case rel @ DataSourceV2Relation(table: ChangelogTable, _, _, _, _, _) =>
+        val changelog = table.changelog
+        val req = evaluateRequirements(changelog, table.changelogInfo)
+
+        var updatedRel: LogicalPlan = rel
+        if (req.requiresCarryOverRemoval || req.requiresUpdateDetection) {
+          updatedRel = addRowLevelPostProcessing(
+            rel, changelog, req.requiresCarryOverRemoval, 
req.requiresUpdateDetection)
+        }
+        if (req.requiresNetChanges) {
+          updatedRel = injectNetChangeComputation(updatedRel, changelog)
+        }
+        updatedRel
+
+      case rel @ StreamingRelationV2(_, _, table: ChangelogTable, _, _, _, _, 
_, _) =>
+        // Streaming CDC reads do not yet apply post-processing. Run the same 
option /
+        // capability validation as the batch path so silent wrong results are 
impossible:
+        // either no post-processing would be required (fall through, return 
raw stream),
+        // or we throw an explicit AnalysisException.
+        val changelog = table.changelog
+        val req = evaluateRequirements(changelog, table.changelogInfo)
+        if (req.needsAny) {
+          throw 
QueryCompilationErrors.cdcStreamingPostProcessingNotSupported(changelog.name())
+        }
+        rel
+    }
+    if (updatedPlan ne plan) {
+      updatedPlan.setTagValue(CHANGELOG_TRANSFORMED_TAG, true)
+    }
+    updatedPlan
+  }
+
+  // 
---------------------------------------------------------------------------
+  // Option validation & Requirement Computation
+  // 
---------------------------------------------------------------------------
+
+  /**
+   * Captures which post-processing passes a CDC query requires, derived from 
the
+   * user-provided [[ChangelogInfo]] options and the connector-declared 
[[Changelog]]
+   * capability flags.
+   */
+  private case class PostProcessingRequirements(
+      requiresCarryOverRemoval: Boolean,
+      requiresUpdateDetection: Boolean,
+      requiresNetChanges: Boolean) {
+    def needsAny: Boolean =
+      requiresCarryOverRemoval || requiresUpdateDetection || requiresNetChanges
+  }
+
+  /**
+   * Validates CDC option/capability combinations and computes which 
post-processing
+   * passes are required. Throws an [[org.apache.spark.sql.AnalysisException]] 
for
+   * unsupported or contradictory combinations (currently: `netChanges` 
deduplication,
+   * and `computeUpdates` with surfaced carry-overs but no carry-over removal).
+   */
+  private def evaluateRequirements(
+      changelog: Changelog,
+      options: ChangelogInfo): PostProcessingRequirements = {
+    // Net change computation is not yet implemented.
+    if (options.deduplicationMode() == 
ChangelogInfo.DeduplicationMode.NET_CHANGES) {
+      throw 
QueryCompilationErrors.cdcNetChangesNotYetSupported(changelog.name())
+    }
+
+    val requiresCarryOverRemoval =
+      options.deduplicationMode() != ChangelogInfo.DeduplicationMode.NONE &&
+        changelog.containsCarryoverRows()
+    val requiresUpdateDetection =
+      options.computeUpdates() && changelog.representsUpdateAsDeleteAndInsert()
+    val requiresNetChanges =
+      options.deduplicationMode() == 
ChangelogInfo.DeduplicationMode.NET_CHANGES &&
+        changelog.containsIntermediateChanges()
+
+    // If carry-overs are surfaced and update detection is enabled without 
carry-over
+    // removal, carry-overs would be falsely classified as updates, leading to 
wrong
+    // results. Hence we throw.
+    if (requiresUpdateDetection &&
+        changelog.containsCarryoverRows() &&
+        options.deduplicationMode() == ChangelogInfo.DeduplicationMode.NONE) {
+      throw QueryCompilationErrors.cdcUpdateDetectionRequiresCarryOverRemoval(
+        changelog.name())
+    }
+
+    PostProcessingRequirements(
+      requiresCarryOverRemoval, requiresUpdateDetection, requiresNetChanges)
+  }
+
+  // 
---------------------------------------------------------------------------
+  // Row Level Post Processing (Update Detection & Carry-over Removal)
+  // 
---------------------------------------------------------------------------
+
+  /**
+   * Adds row-level post-processing (carry-over removal and/or update 
detection) on top of
+   * the given plan:
+   *   - both active    -> Window(counts + rv bounds) -> Filter -> 
Project(relabel) -> Drop helpers

Review Comment:
   Can you clarify what counts and rv bounds are in the comment



##########
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/ResolveChangelogTable.scala:
##########
@@ -0,0 +1,315 @@
+/*
+ * 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.
+ */
+
+package org.apache.spark.sql.catalyst.analysis
+
+import org.apache.spark.sql.catalyst.expressions._
+import org.apache.spark.sql.catalyst.expressions.aggregate.{Count, Max, Min}
+import org.apache.spark.sql.catalyst.plans.logical._
+import org.apache.spark.sql.catalyst.rules.Rule
+import org.apache.spark.sql.catalyst.streaming.StreamingRelationV2
+import org.apache.spark.sql.catalyst.trees.TreeNodeTag
+import org.apache.spark.sql.connector.catalog.{Changelog, ChangelogInfo}
+import org.apache.spark.sql.errors.QueryCompilationErrors
+import org.apache.spark.sql.execution.datasources.v2.{ChangelogTable, 
DataSourceV2Relation}
+import org.apache.spark.sql.types.{IntegerType, StringType}
+
+/**
+ * Post-processes a resolved [[ChangelogTable]] read to apply CDC option 
semantics
+ * (carry-over removal, update detection) and to enforce supported option 
combinations.
+ *
+ * Fires after [[ResolveRelations]] has wrapped the connector's [[Changelog]] 
in a
+ * [[ChangelogTable]]. Both batch ([[DataSourceV2Relation]]) and streaming
+ * ([[StreamingRelationV2]]) reads are handled:
+ *   - Batch: the requested post-processing passes are injected as logical 
operators on top
+ *     of the relation. Carry-over removal and update detection are fused into 
a single
+ *     pass over a (rowId, _commit_version)-partitioned Window: the Filter 
drops CoW
+ *     carry-over pairs (same rowVersion on both sides) and the subsequent 
Project relabels
+ *     real delete+insert pairs as update_preimage / update_postimage.
+ *   - Streaming: post-processing is not yet supported. If the requested 
options would
+ *     require any post-processing, the rule throws an explicit 
[[AnalysisException]] to
+ *     prevent silent wrong results. Streams that don't require 
post-processing pass
+ *     through unchanged.
+ *
+ * Net change computation (`deduplicationMode = netChanges`) is not yet 
implemented and
+ * is rejected up-front for both batch and streaming.
+ */
+object ResolveChangelogTable extends Rule[LogicalPlan] {
+
+  private val CHANGELOG_TRANSFORMED_TAG =
+    TreeNodeTag[Boolean]("changelog_transformed")
+
+  private object HelperColumn {
+    final val DelCnt = "_del_cnt"
+    final val InsCnt = "_ins_cnt"
+    final val MinRv = "_min_rv"
+    final val MaxRv = "_max_rv"
+
+    val all: Set[String] = Set(DelCnt, InsCnt, MinRv, MaxRv)
+  }
+
+  override def apply(plan: LogicalPlan): LogicalPlan = {
+    if (isAlreadyTransformed(plan)) return plan
+    var updatedPlan = plan

Review Comment:
   ```suggestion
       val updatedPlan = plan
   ```



##########
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/ResolveChangelogTable.scala:
##########
@@ -0,0 +1,315 @@
+/*
+ * 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.
+ */
+
+package org.apache.spark.sql.catalyst.analysis
+
+import org.apache.spark.sql.catalyst.expressions._
+import org.apache.spark.sql.catalyst.expressions.aggregate.{Count, Max, Min}
+import org.apache.spark.sql.catalyst.plans.logical._
+import org.apache.spark.sql.catalyst.rules.Rule
+import org.apache.spark.sql.catalyst.streaming.StreamingRelationV2
+import org.apache.spark.sql.catalyst.trees.TreeNodeTag
+import org.apache.spark.sql.connector.catalog.{Changelog, ChangelogInfo}
+import org.apache.spark.sql.errors.QueryCompilationErrors
+import org.apache.spark.sql.execution.datasources.v2.{ChangelogTable, 
DataSourceV2Relation}
+import org.apache.spark.sql.types.{IntegerType, StringType}
+
+/**
+ * Post-processes a resolved [[ChangelogTable]] read to apply CDC option 
semantics
+ * (carry-over removal, update detection) and to enforce supported option 
combinations.
+ *
+ * Fires after [[ResolveRelations]] has wrapped the connector's [[Changelog]] 
in a
+ * [[ChangelogTable]]. Both batch ([[DataSourceV2Relation]]) and streaming
+ * ([[StreamingRelationV2]]) reads are handled:
+ *   - Batch: the requested post-processing passes are injected as logical 
operators on top
+ *     of the relation. Carry-over removal and update detection are fused into 
a single
+ *     pass over a (rowId, _commit_version)-partitioned Window: the Filter 
drops CoW
+ *     carry-over pairs (same rowVersion on both sides) and the subsequent 
Project relabels
+ *     real delete+insert pairs as update_preimage / update_postimage.
+ *   - Streaming: post-processing is not yet supported. If the requested 
options would
+ *     require any post-processing, the rule throws an explicit 
[[AnalysisException]] to
+ *     prevent silent wrong results. Streams that don't require 
post-processing pass
+ *     through unchanged.
+ *
+ * Net change computation (`deduplicationMode = netChanges`) is not yet 
implemented and
+ * is rejected up-front for both batch and streaming.
+ */
+object ResolveChangelogTable extends Rule[LogicalPlan] {
+
+  private val CHANGELOG_TRANSFORMED_TAG =
+    TreeNodeTag[Boolean]("changelog_transformed")
+
+  private object HelperColumn {
+    final val DelCnt = "_del_cnt"
+    final val InsCnt = "_ins_cnt"
+    final val MinRv = "_min_rv"
+    final val MaxRv = "_max_rv"
+
+    val all: Set[String] = Set(DelCnt, InsCnt, MinRv, MaxRv)
+  }
+
+  override def apply(plan: LogicalPlan): LogicalPlan = {
+    if (isAlreadyTransformed(plan)) return plan
+    var updatedPlan = plan
+    updatedPlan = plan.resolveOperatorsUp {
+      case rel @ DataSourceV2Relation(table: ChangelogTable, _, _, _, _, _) =>
+        val changelog = table.changelog
+        val req = evaluateRequirements(changelog, table.changelogInfo)
+
+        var updatedRel: LogicalPlan = rel
+        if (req.requiresCarryOverRemoval || req.requiresUpdateDetection) {
+          updatedRel = addRowLevelPostProcessing(
+            rel, changelog, req.requiresCarryOverRemoval, 
req.requiresUpdateDetection)
+        }
+        if (req.requiresNetChanges) {
+          updatedRel = injectNetChangeComputation(updatedRel, changelog)
+        }
+        updatedRel
+
+      case rel @ StreamingRelationV2(_, _, table: ChangelogTable, _, _, _, _, 
_, _) =>
+        // Streaming CDC reads do not yet apply post-processing. Run the same 
option /
+        // capability validation as the batch path so silent wrong results are 
impossible:
+        // either no post-processing would be required (fall through, return 
raw stream),
+        // or we throw an explicit AnalysisException.
+        val changelog = table.changelog
+        val req = evaluateRequirements(changelog, table.changelogInfo)
+        if (req.needsAny) {
+          throw 
QueryCompilationErrors.cdcStreamingPostProcessingNotSupported(changelog.name())
+        }
+        rel
+    }
+    if (updatedPlan ne plan) {
+      updatedPlan.setTagValue(CHANGELOG_TRANSFORMED_TAG, true)
+    }
+    updatedPlan
+  }
+
+  // 
---------------------------------------------------------------------------
+  // Option validation & Requirement Computation
+  // 
---------------------------------------------------------------------------
+
+  /**
+   * Captures which post-processing passes a CDC query requires, derived from 
the
+   * user-provided [[ChangelogInfo]] options and the connector-declared 
[[Changelog]]
+   * capability flags.
+   */
+  private case class PostProcessingRequirements(
+      requiresCarryOverRemoval: Boolean,
+      requiresUpdateDetection: Boolean,
+      requiresNetChanges: Boolean) {
+    def needsAny: Boolean =
+      requiresCarryOverRemoval || requiresUpdateDetection || requiresNetChanges
+  }
+
+  /**
+   * Validates CDC option/capability combinations and computes which 
post-processing
+   * passes are required. Throws an [[org.apache.spark.sql.AnalysisException]] 
for
+   * unsupported or contradictory combinations (currently: `netChanges` 
deduplication,
+   * and `computeUpdates` with surfaced carry-overs but no carry-over removal).
+   */
+  private def evaluateRequirements(
+      changelog: Changelog,
+      options: ChangelogInfo): PostProcessingRequirements = {
+    // Net change computation is not yet implemented.
+    if (options.deduplicationMode() == 
ChangelogInfo.DeduplicationMode.NET_CHANGES) {
+      throw 
QueryCompilationErrors.cdcNetChangesNotYetSupported(changelog.name())
+    }
+
+    val requiresCarryOverRemoval =
+      options.deduplicationMode() != ChangelogInfo.DeduplicationMode.NONE &&
+        changelog.containsCarryoverRows()
+    val requiresUpdateDetection =
+      options.computeUpdates() && changelog.representsUpdateAsDeleteAndInsert()
+    val requiresNetChanges =
+      options.deduplicationMode() == 
ChangelogInfo.DeduplicationMode.NET_CHANGES &&
+        changelog.containsIntermediateChanges()
+
+    // If carry-overs are surfaced and update detection is enabled without 
carry-over
+    // removal, carry-overs would be falsely classified as updates, leading to 
wrong
+    // results. Hence we throw.
+    if (requiresUpdateDetection &&
+        changelog.containsCarryoverRows() &&
+        options.deduplicationMode() == ChangelogInfo.DeduplicationMode.NONE) {
+      throw QueryCompilationErrors.cdcUpdateDetectionRequiresCarryOverRemoval(
+        changelog.name())
+    }
+
+    PostProcessingRequirements(
+      requiresCarryOverRemoval, requiresUpdateDetection, requiresNetChanges)
+  }
+
+  // 
---------------------------------------------------------------------------
+  // Row Level Post Processing (Update Detection & Carry-over Removal)
+  // 
---------------------------------------------------------------------------
+
+  /**
+   * Adds row-level post-processing (carry-over removal and/or update 
detection) on top of
+   * the given plan:
+   *   - both active    -> Window(counts + rv bounds) -> Filter -> 
Project(relabel) -> Drop helpers
+   *   - carry-over only -> Window(counts + rv bounds) -> Filter -> Drop 
helpers
+   *   - update only    -> Window(counts only) -> Project(relabel) -> Drop 
helpers
+   *   - neither        -> not invoked (caller guards this case)
+   */
+  private def addRowLevelPostProcessing(
+      plan: LogicalPlan,
+      cl: Changelog,
+      requiresCarryOverRemoval: Boolean,
+      requiresUpdateDetection: Boolean): LogicalPlan = {
+    // Row-version bounds in the Window are needed iff we filter carry-over 
pairs.
+    var modifiedPlan = addPostProcessingWindow(plan, cl,
+      includeRowVersionBounds = requiresCarryOverRemoval)
+    if (requiresCarryOverRemoval) modifiedPlan = 
addCarryOverPairFilter(modifiedPlan)
+    if (requiresUpdateDetection) modifiedPlan = 
addUpdateRelabelProjection(modifiedPlan)
+    removeHelperColumns(modifiedPlan)
+  }
+
+  /**
+   * Adds a Window node partitioned by (rowId, _commit_version) that computes
+   * `_del_cnt` and `_ins_cnt` per partition, and, when 
`includeRowVersionBounds`
+   * is true, additionally `_min_rv` / `_max_rv` (min/max of 
`Changelog.rowVersion()`).
+   *
+   * `_del_cnt` / `_ins_cnt` drive update detection (1 each -> relabel as
+   * update_preimage / update_postimage). `_min_rv` / `_max_rv` drive 
carry-over
+   * detection (within a delete+insert pair, equal bounds signal a CoW 
carry-over).
+   */
+  private def addPostProcessingWindow(
+      plan: LogicalPlan,
+      cl: Changelog,
+      includeRowVersionBounds: Boolean): LogicalPlan = {
+    val changeTypeAttr = getAttribute(plan, "_change_type")

Review Comment:
   It would be helpful to define these names as constant somewhere so that 
connectors can reuse them instead of redefining their own



##########
sql/core/src/test/scala/org/apache/spark/sql/connector/ResolveChangelogTablePostProcessingSuite.scala:
##########
@@ -0,0 +1,945 @@
+/*
+ * 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.
+ */
+
+package org.apache.spark.sql.connector
+
+import java.util.Collections
+
+import org.scalatest.BeforeAndAfterEach
+
+import org.apache.spark.SparkRuntimeException
+import org.apache.spark.sql.{AnalysisException, QueryTest}
+import org.apache.spark.sql.catalyst.InternalRow
+import org.apache.spark.sql.connector.catalog.{
+  ChangelogProperties, Column, Identifier, InMemoryChangelogCatalog}
+import org.apache.spark.sql.connector.expressions.Transform
+import org.apache.spark.sql.test.SharedSparkSession
+import org.apache.spark.sql.types.{
+  BinaryType, BooleanType, DoubleType, LongType, StringType, StructField, 
StructType}
+import org.apache.spark.unsafe.types.UTF8String
+
+/**
+ * Tests for [[org.apache.spark.sql.catalyst.analysis.ResolveChangelogTable]] 
using the
+ * in-memory changelog catalog. These tests don't depend on Delta or any 
specific connector;
+ * they directly control what the connector "returns" by populating the 
in-memory changelog
+ * with hand-crafted change rows.
+ *
+ * Each test sets up [[ChangelogProperties]] on the catalog to enable specific 
post-processing
+ * paths (carry-over removal, update detection) and then verifies that Spark's 
analyzer rule
+ * correctly transforms the plan and produces the expected output.
+ */
+class ResolveChangelogTablePostProcessingSuite

Review Comment:
   write a test for streaming without post processing



##########
sql/core/src/test/scala/org/apache/spark/sql/connector/ResolveChangelogTablePostProcessingSuite.scala:
##########
@@ -0,0 +1,945 @@
+/*
+ * 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.
+ */
+
+package org.apache.spark.sql.connector
+
+import java.util.Collections
+
+import org.scalatest.BeforeAndAfterEach
+
+import org.apache.spark.SparkRuntimeException
+import org.apache.spark.sql.{AnalysisException, QueryTest}
+import org.apache.spark.sql.catalyst.InternalRow
+import org.apache.spark.sql.connector.catalog.{
+  ChangelogProperties, Column, Identifier, InMemoryChangelogCatalog}
+import org.apache.spark.sql.connector.expressions.Transform
+import org.apache.spark.sql.test.SharedSparkSession
+import org.apache.spark.sql.types.{
+  BinaryType, BooleanType, DoubleType, LongType, StringType, StructField, 
StructType}
+import org.apache.spark.unsafe.types.UTF8String
+
+/**
+ * Tests for [[org.apache.spark.sql.catalyst.analysis.ResolveChangelogTable]] 
using the
+ * in-memory changelog catalog. These tests don't depend on Delta or any 
specific connector;
+ * they directly control what the connector "returns" by populating the 
in-memory changelog
+ * with hand-crafted change rows.
+ *
+ * Each test sets up [[ChangelogProperties]] on the catalog to enable specific 
post-processing
+ * paths (carry-over removal, update detection) and then verifies that Spark's 
analyzer rule
+ * correctly transforms the plan and produces the expected output.
+ */
+class ResolveChangelogTablePostProcessingSuite
+    extends QueryTest
+    with SharedSparkSession
+    with BeforeAndAfterEach {
+
+  private val catalogName = "cdc_test_catalog"
+  private val testTableName = "events"
+
+  override def beforeAll(): Unit = {
+    super.beforeAll()
+    spark.conf.set(
+      s"spark.sql.catalog.$catalogName",
+      classOf[InMemoryChangelogCatalog].getName)
+  }
+
+  override def beforeEach(): Unit = {
+    super.beforeEach()
+    val cat = catalog
+    val ident = Identifier.of(Array.empty, testTableName)
+    if (cat.tableExists(ident)) cat.dropTable(ident)
+    cat.clearChangeRows(ident)
+    cat.setChangelogProperties(ident, ChangelogProperties())
+    cat.createTable(
+      ident,
+      Array(
+        Column.create("id", LongType),
+        Column.create("name", StringType),
+        Column.create("row_commit_version", LongType, false)),
+      Array.empty[Transform],
+      Collections.emptyMap[String, String]())
+  }
+
+  private def catalog: InMemoryChangelogCatalog = {
+    spark.sessionState.catalogManager
+      .catalog(catalogName)
+      .asInstanceOf[InMemoryChangelogCatalog]
+  }
+
+  private def ident = Identifier.of(Array.empty, testTableName)
+
+  /**
+   * Helper to create a change row matching schema
+   * (id, name, row_commit_version, _change_type, _commit_version, 
_commit_timestamp).
+   *
+   * `rowCommitVersion` follows Delta row-tracking semantics: carry-over pairs 
(CoW-rewritten
+   * unchanged rows) share the same value on both sides; real updates carry 
the OLD value on
+   * the delete side and the NEW value on the insert side. Defaults to 
`commitVersion` for
+   * tests that don't exercise carry-over removal.
+   */
+  private def changeRow(
+      id: Long,
+      name: String,
+      changeType: String,
+      commitVersion: Long,
+      rowCommitVersion: Long = -1L,
+      commitTimestamp: Long = 0L): InternalRow = {
+    val rcv = if (rowCommitVersion == -1L) commitVersion else rowCommitVersion
+    InternalRow(
+      id,
+      UTF8String.fromString(name),
+      rcv,
+      UTF8String.fromString(changeType),
+      commitVersion,
+      commitTimestamp)
+  }
+
+  // 
===========================================================================
+  // Carry-Over Removal
+  // 
===========================================================================
+
+  test("carry-over removal drops identical delete+insert pairs") {
+    catalog.setChangelogProperties(ident, ChangelogProperties(
+      containsCarryoverRows = true,
+      rowIdNames = Seq("id"),
+      rowVersionName = Some("row_commit_version")))
+
+    // v1: insert Alice and Bob (rcv=1 each)
+    // v2: real delete Alice (preimage carries old rcv=1);
+    //     carry-over for Bob (CoW, rcv unchanged on both sides)
+    catalog.addChangeRows(ident, Seq(
+      changeRow(1L, "Alice", "insert", 1L, rowCommitVersion = 1L),
+      changeRow(2L, "Bob", "insert", 1L, rowCommitVersion = 1L),
+      changeRow(1L, "Alice", "delete", 2L, rowCommitVersion = 1L),
+      changeRow(2L, "Bob", "delete", 2L, rowCommitVersion = 1L),  // carry-over
+      changeRow(2L, "Bob", "insert", 2L, rowCommitVersion = 1L))) // 
carry-over (same rcv)
+
+    val rows = sql(

Review Comment:
   Use `checkAnswer()` to validate results



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