Port of DH-13185: fix FunctionalColumn

engine/table/src/main/java/io/deephaven/engine/table/impl/select/FunctionalColumn.java

@@ -176,7 +176,7 @@ public void fillPrevChunk(@NotNull FillContext fillContext,
                     @NotNull final WritableChunk<? super Values> destination,
                     @NotNull final RowSequence rowSequence) {
                 final FunctionalColumnFillContext ctx = (FunctionalColumnFillContext) fillContext;
-                ctx.chunkFiller.fillByIndices(this, rowSequence, destination);
+                ctx.chunkFiller.fillPrevByIndices(this, rowSequence, destination);
             }
         }, false);
     }

engine/table/src/main/java/io/deephaven/engine/table/impl/select/MultiSourceFunctionalColumn.java

@@ -172,7 +172,7 @@ public void fillPrevChunk(@NotNull FillContext fillContext,
                     @NotNull final WritableChunk<? super Values> destination,
                     @NotNull final RowSequence rowSequence) {
                 final FunctionalColumnFillContext ctx = (FunctionalColumnFillContext) fillContext;
-                ctx.chunkFiller.fillByIndices(this, rowSequence, destination);
+                ctx.chunkFiller.fillPrevByIndices(this, rowSequence, destination);
             }
         }, false);
     }

engine/table/src/test/java/io/deephaven/engine/table/impl/remote/TestConstructSnapshot.java

@@ -5,13 +5,31 @@
 
 import io.deephaven.base.SleepUtil;
 import io.deephaven.engine.context.ExecutionContext;
+import io.deephaven.engine.rowset.RowSetFactory;
+import io.deephaven.engine.table.impl.QueryTable;
+import io.deephaven.engine.table.impl.select.FunctionalColumn;
 import io.deephaven.engine.testutil.ControlledUpdateGraph;
 import io.deephaven.engine.testutil.testcase.RefreshingTableTestCase;
 import io.deephaven.engine.updategraph.LogicalClock;
 import io.deephaven.engine.updategraph.UpdateGraph;
+import io.deephaven.engine.util.TableTools;
 import io.deephaven.util.SafeCloseable;
+import io.deephaven.util.thread.NamingThreadFactory;
 import org.apache.commons.lang3.mutable.MutableLong;
 
+import java.util.BitSet;
+import java.util.List;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+import static io.deephaven.engine.testutil.TstUtils.addToTable;
+import static io.deephaven.engine.testutil.TstUtils.assertTableEquals;
+import static io.deephaven.engine.testutil.TstUtils.i;
+import static io.deephaven.engine.testutil.TstUtils.testRefreshingTable;
+import static io.deephaven.engine.util.TableTools.intCol;
+import static io.deephaven.engine.util.TableTools.stringCol;
+
 public class TestConstructSnapshot extends RefreshingTableTestCase {
 
     public void testClockChange() throws InterruptedException {
@@ -64,4 +82,74 @@ public UpdateGraph getUpdateGraph() {
         t2.join();
         assertEquals(1, changed.longValue());
     }
+
+    public void testUsePrevSnapshot() throws ExecutionException, InterruptedException {
+        final ExecutorService executor = Executors.newSingleThreadExecutor(
+                new NamingThreadFactory(TestConstructSnapshot.class, "TestConstructSnapshot Executor"));
+
+        final QueryTable table = testRefreshingTable(i(1000).toTracking(), intCol("I", 10));
+        FunctionalColumn<Integer, String> plusOneColumn =
+                new FunctionalColumn<>("I", Integer.class, "S2", String.class, (Integer i) -> Integer.toString(i + 1));
+        final QueryTable functionalTable = (QueryTable) table.updateView(List.of(plusOneColumn));
+
+        TableTools.show(functionalTable);
+
+        final BitSet oneBit = new BitSet();
+        oneBit.set(0);
+        final BitSet twoBits = new BitSet();
+        twoBits.set(0);
+        twoBits.set(1);
+        final InitialSnapshot initialSnapshot = ConstructSnapshot.constructInitialSnapshotInPositionSpace(table, table,
+                oneBit, RowSetFactory.fromRange(0, 10));
+        final InitialSnapshot funcSnapshot = ConstructSnapshot.constructInitialSnapshotInPositionSpace(functionalTable,
+                functionalTable, twoBits, RowSetFactory.fromRange(0, 10));
+
+        final InitialSnapshotTable initialSnapshotTable =
+                InitialSnapshotTable.setupInitialSnapshotTable(table.getDefinition(), initialSnapshot);
+        TableTools.showWithRowSet(initialSnapshotTable);
+
+        final InitialSnapshotTable funcSnapshotTable =
+                InitialSnapshotTable.setupInitialSnapshotTable(functionalTable.getDefinition(), funcSnapshot);
+        TableTools.showWithRowSet(funcSnapshotTable);
+
+        assertTableEquals(TableTools.newTable(intCol("I", 10)), initialSnapshotTable);
+        assertTableEquals(TableTools.newTable(intCol("I", 10), stringCol("S2", "11")), funcSnapshotTable);
+
+        ExecutionContext.getContext().getUpdateGraph().<ControlledUpdateGraph>cast().startCycleForUnitTests();
+        addToTable(table, i(1000), intCol("I", 20));
+        final InitialSnapshot initialSnapshot2 = executor.submit(() -> ConstructSnapshot
+                .constructInitialSnapshotInPositionSpace(table, table, oneBit, RowSetFactory.fromRange(0, 10))).get();
+        final InitialSnapshot funcSnapshot2 =
+                executor.submit(() -> ConstructSnapshot.constructInitialSnapshotInPositionSpace(functionalTable,
+                        functionalTable, twoBits, RowSetFactory.fromRange(0, 10))).get();
+        table.notifyListeners(i(), i(), i(1000));
+
+        while (ExecutionContext.getContext().getUpdateGraph().<ControlledUpdateGraph>cast()
+                .flushOneNotificationForUnitTests());
+
+        final InitialSnapshot initialSnapshot3 = executor.submit(() -> ConstructSnapshot
+                .constructInitialSnapshotInPositionSpace(table, table, oneBit, RowSetFactory.fromRange(0, 10))).get();
+        final InitialSnapshot funcSnapshot3 =
+                executor.submit(() -> ConstructSnapshot.constructInitialSnapshotInPositionSpace(functionalTable,
+                        functionalTable, twoBits, RowSetFactory.fromRange(0, 10))).get();
+        ExecutionContext.getContext().getUpdateGraph().<ControlledUpdateGraph>cast().completeCycleForUnitTests();
+
+        final InitialSnapshotTable initialSnapshotTable2 =
+                InitialSnapshotTable.setupInitialSnapshotTable(table.getDefinition(), initialSnapshot2);
+        final InitialSnapshotTable initialSnapshotTable3 =
+                InitialSnapshotTable.setupInitialSnapshotTable(table.getDefinition(), initialSnapshot3);
+
+        assertTableEquals(TableTools.newTable(intCol("I", 10)), initialSnapshotTable2);
+        assertTableEquals(TableTools.newTable(intCol("I", 20)), initialSnapshotTable3);
+
+        final InitialSnapshotTable funcSnapshotTable2 =
+                InitialSnapshotTable.setupInitialSnapshotTable(functionalTable.getDefinition(), funcSnapshot2);
+        final InitialSnapshotTable funcSnapshotTable3 =
+                InitialSnapshotTable.setupInitialSnapshotTable(functionalTable.getDefinition(), funcSnapshot3);
+
+        assertTableEquals(TableTools.newTable(intCol("I", 10), stringCol("S2", "11")), funcSnapshotTable2);
+        assertTableEquals(TableTools.newTable(intCol("I", 20), stringCol("S2", "21")), funcSnapshotTable3);
+
+        executor.shutdownNow();
+    }
 }