rubenada commented on a change in pull request #2329:
URL: https://github.com/apache/calcite/pull/2329#discussion_r562005253



##########
File path: 
linq4j/src/main/java/org/apache/calcite/linq4j/EnumerableDefaults.java
##########
@@ -4683,4 +4683,191 @@ private void flush() {
       }
     };
   }
+
+  /**
+   * Merge Union Enumerable.
+   * Performs a union (or union all) of all its inputs (which must be already 
sorted),
+   * respecting the order.
+   *
+   * @param sources input enumerables (must be already sorted)
+   * @param sortKeySelector sort key selector
+   * @param sortComparator sort comparator to decide the next item
+   * @param all whether duplicates will be considered or not
+   * @param equalityComparer {@link EqualityComparer} to control duplicates,
+   *                         only used if {@code all} is {@code false}
+   * @param <TSource> record type
+   * @param <TKey> sort key
+   */
+  public static <TSource, @Nullable TKey> Enumerable<TSource> mergeUnion(

Review comment:
       I understand. The complication is that this `sortKeySelector` is / can 
be created by dynamic code (`PhysTpe#generateCollationKey`), and (it's not so 
easy to guess) I believe a null in there can lead to a NPE.
   I have committed a new workaround based on 
`@SuppressWarnings("argument.type.incompatible")`




----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

For queries about this service, please contact Infrastructure at:
[email protected]


Reply via email to