[CALCITE-5949] RexExecutable should return unchanged original express…

…ions when it fails

Co-authored-by: arkanovicz <claude@renegat.net>

core/src/main/java/org/apache/calcite/rex/RexExecutable.java

@@ -32,6 +32,7 @@
 import java.io.StringReader;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
@@ -87,11 +88,14 @@ public void reduce(RexBuilder rexBuilder, List<RexNode> constExps,
         values = new Object[constExps.size()];
       } else {
         assert values.length == constExps.size();
+        final List<RexNode> successfullyReduced = new ArrayList<>(constExps.size());
         final List<@Nullable Object> valueList = Arrays.asList(values);
         for (Pair<RexNode, @Nullable Object> value : Pair.zip(constExps, valueList)) {
-          reducedValues.add(
+          successfullyReduced.add(
               rexBuilder.makeLiteral(value.right, value.left.getType(), true));
         }
+        assert successfullyReduced.size() == constExps.size();
+        reducedValues.addAll(successfullyReduced);
       }
     } catch (RuntimeException e) {
       // One or more of the expressions failed.

core/src/test/java/org/apache/calcite/rex/RexExecutorTest.java

@@ -378,4 +378,28 @@ public void run() {
   interface Action {
     void check(RexBuilder rexBuilder, RexExecutorImpl executor);
   }
+
+  /** Test case for
+   * <a href="https://issues.apache.org/jira/browse/CALCITE-5949">[CALCITE-5949]
+   * RexExecutable should return unchanged original expressions when it fails</a>.
+   */
+  @Test void testInvalidExpressionInList() {
+    check((rexBuilder, executor) -> {
+      final List<RexNode> reducedValues = new ArrayList<>();
+      final RelDataTypeFactory typeFactory = rexBuilder.getTypeFactory();
+      final RelDataType integer =
+          typeFactory.createSqlType(SqlTypeName.INTEGER);
+      final RexCall first =
+          (RexCall) rexBuilder.makeCall(SqlStdOperatorTable.LN,
+          rexBuilder.makeLiteral(3, integer, true));
+      final RexCall second =
+          (RexCall) rexBuilder.makeCall(SqlStdOperatorTable.LN,
+          rexBuilder.makeLiteral(-2, integer, true));
+      executor.reduce(rexBuilder, ImmutableList.of(first, second),
+          reducedValues);
+      assertThat(reducedValues, hasSize(2));
+      assertThat(reducedValues.get(0), instanceOf(RexCall.class));
+      assertThat(reducedValues.get(1), instanceOf(RexCall.class));
+    });
+  }
 }