From 76f27bec85364d1b397ff7764d5ed7299ca465fb Mon Sep 17 00:00:00 2001
From: Nate Bauernfeind <natebauernfeind@deephaven.io>
Date: Wed, 21 Aug 2024 14:30:18 -0600
Subject: [PATCH] fix: Parallel Where should not NPE on a Big TableUpdate With
 Both Adds and Mods (#5961)

---
 .../table/impl/AbstractFilterExecution.java   |  4 +-
 .../impl/QueryTableWhereParallelTest.java     | 48 +++++++++++++++++++
 2 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/engine/table/src/main/java/io/deephaven/engine/table/impl/AbstractFilterExecution.java b/engine/table/src/main/java/io/deephaven/engine/table/impl/AbstractFilterExecution.java
index 3659e8bb530..6c388b3ee7d 100644
--- a/engine/table/src/main/java/io/deephaven/engine/table/impl/AbstractFilterExecution.java
+++ b/engine/table/src/main/java/io/deephaven/engine/table/impl/AbstractFilterExecution.java
@@ -190,12 +190,12 @@ private void doFilterParallel(
                         // Clean up the row sets created by the filter.
                         try (final RowSet ignored = adds;
                                 final RowSet ignored2 = mods) {
-                            if (addedResult != null) {
+                            if (addedResult != null && adds != null) {
                                 synchronized (addedResult) {
                                     addedResult.insert(adds);
                                 }
                             }
-                            if (modifiedResult != null) {
+                            if (modifiedResult != null && mods != null) {
                                 synchronized (modifiedResult) {
                                     modifiedResult.insert(mods);
                                 }
diff --git a/engine/table/src/test/java/io/deephaven/engine/table/impl/QueryTableWhereParallelTest.java b/engine/table/src/test/java/io/deephaven/engine/table/impl/QueryTableWhereParallelTest.java
index 65b27a6b380..0659f11a139 100644
--- a/engine/table/src/test/java/io/deephaven/engine/table/impl/QueryTableWhereParallelTest.java
+++ b/engine/table/src/test/java/io/deephaven/engine/table/impl/QueryTableWhereParallelTest.java
@@ -5,12 +5,23 @@
 
 import gnu.trove.list.TLongList;
 import gnu.trove.list.array.TLongArrayList;
+import io.deephaven.engine.context.ExecutionContext;
 import io.deephaven.engine.rowset.RowSet;
+import io.deephaven.engine.rowset.RowSetFactory;
+import io.deephaven.engine.rowset.RowSetShiftData;
 import io.deephaven.engine.rowset.WritableRowSet;
+import io.deephaven.engine.table.ModifiedColumnSet;
 import io.deephaven.engine.table.Table;
 import io.deephaven.engine.table.TableDefinition;
+import io.deephaven.engine.table.TableUpdate;
 import io.deephaven.engine.table.impl.select.WhereFilter;
 import io.deephaven.engine.table.impl.select.WhereFilterImpl;
+import io.deephaven.engine.table.impl.sources.RowKeyColumnSource;
+import io.deephaven.engine.table.impl.sources.RowPositionColumnSource;
+import io.deephaven.engine.testutil.ControlledUpdateGraph;
+import io.deephaven.engine.testutil.EvalNugget;
+import io.deephaven.engine.testutil.EvalNuggetInterface;
+import io.deephaven.engine.testutil.TstUtils;
 import io.deephaven.engine.util.TableTools;
 import io.deephaven.test.types.OutOfBandTest;
 import org.jetbrains.annotations.NotNull;
@@ -21,6 +32,7 @@
 
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 
 import static org.junit.Assert.assertEquals;
 
@@ -119,4 +131,40 @@ public WhereFilter copy() {
             QueryTable.PARALLEL_WHERE_ROWS_PER_SEGMENT = oldSize;
         }
     }
+
+    @Test
+    public void testParallelExecutionViaTableUpdate() {
+        final ControlledUpdateGraph updateGraph = ExecutionContext.getContext().getUpdateGraph().cast();
+
+        final long oldSize = QueryTable.PARALLEL_WHERE_ROWS_PER_SEGMENT;
+        try {
+            QueryTable.PARALLEL_WHERE_ROWS_PER_SEGMENT = 1_000;
+            final QueryTable table = TstUtils.testRefreshingTable(RowSetFactory.flat(1500).toTracking())
+                    .withAdditionalColumns(Map.of("K", new RowKeyColumnSource()));
+            table.setRefreshing(true);
+            table.setAttribute(BaseTable.TEST_SOURCE_TABLE_ATTRIBUTE, true);
+            final Table source = table.updateView("J = ii % 2 == 0 ? K : 0");
+
+            final EvalNuggetInterface[] en = new EvalNuggetInterface[] {
+                    EvalNugget.from(() -> source.where("K == J")),
+            };
+
+            updateGraph.runWithinUnitTestCycle(() -> {
+                final RowSet added = RowSetFactory.fromRange(1500, 2999);
+                final RowSet modified = RowSetFactory.fromRange(0, 1499);
+                table.getRowSet().writableCast().insert(added);
+
+                final TableUpdate upstream = new TableUpdateImpl(
+                        added, RowSetFactory.empty(), modified, RowSetShiftData.EMPTY, ModifiedColumnSet.ALL);
+
+                table.notifyListeners(upstream);
+            });
+
+            // Ensure the table is as expected.
+            TstUtils.validate(en);
+
+        } finally {
+            QueryTable.PARALLEL_WHERE_ROWS_PER_SEGMENT = oldSize;
+        }
+    }
 }