kennknowles commented on a change in pull request #14059:
URL: https://github.com/apache/beam/pull/14059#discussion_r583236807
##########
File path:
sdks/java/core/src/main/java/org/apache/beam/sdk/util/IdentityWindowFn.java
##########
@@ -25,26 +25,19 @@
import org.apache.beam.sdk.transforms.GroupByKey;
import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
import org.apache.beam.sdk.transforms.windowing.IncompatibleWindowException;
-import org.apache.beam.sdk.transforms.windowing.InvalidWindows;
import org.apache.beam.sdk.transforms.windowing.NonMergingWindowFn;
import org.apache.beam.sdk.transforms.windowing.Window;
import org.apache.beam.sdk.transforms.windowing.WindowFn;
import org.apache.beam.sdk.transforms.windowing.WindowMappingFn;
import org.apache.beam.sdk.values.PCollection;
-import org.apache.beam.sdk.values.WindowingStrategy;
import org.joda.time.Instant;
/**
* A {@link WindowFn} that leaves all associations between elements and
windows unchanged.
*
* <p>This {@link WindowFn} is applied when elements must be passed through a
{@link GroupByKey},
- * but should maintain their existing {@link Window} assignments. Because
windows may have been
- * merged, the earlier {@link WindowFn} may not appropriately maintain the
existing window
- * assignments. For example, if the earlier {@link WindowFn} merges windows,
after a {@link
- * GroupByKey} the {@link WindowingStrategy} uses {@link InvalidWindows}, and
no further {@link
- * GroupByKey} can be applied without applying a new {@link WindowFn}. This
{@link WindowFn} allows
- * existing window assignments to be maintained across a single group by key,
at which point the
- * earlier {@link WindowingStrategy} should be restored.
+ * but should maintain their existing {@link Window} assignments. This will
prevent merging if the
Review comment:
This reminds me that you caught a bug: even if the user does use
`Window.into(merging windowfn)` this will use `Window.configure()` that will
keep the already merged bit. I will update the PR to reset the "already merged"
bit whenever the WindowFn changes.
----------------------------------------------------------------
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]
