[BEAM-2808] Improve error message when DoFn @ProcessElement has the wrong window type

• Type: Improvement
• Status: Resolved
• Priority: P3
• Resolution: Fixed
• Fix Version/s: 2.2.0
• Component/s: sdk-java-core
• Labels: Done starter
• Assignee: Daniel Oliveira
• Reporter: Kenneth Knowles
• Created: 25/Aug/17 17:19
• Updated: 06/Oct/20 21:50
• Resolved: 17/Jan/18 01:16

Description

The message today is something like this:

processElement(org.apache.beam.sdk.transforms.DoFn$ProcessContext,org.apache.beam.sdk.transforms.windowing.IntervalWindow) expects window type org.apache.beam.sdk.transforms.windowing.IntervalWindow, which is not a supertype of actual window type org.apache.beam.sdk.transforms.windowing.GlobalWindow

Someone suggested this:

processElement(org.apache.beam.sdk.transforms.DoFn$ProcessContext,org.apache.beam.sdk.transforms.windowing.IntervalWindow) unable to provide window --  expects window type org.apache.beam.sdk.transforms.windowing.IntervalWindow (from parameter), which is not a supertype of actual window type org.apache.beam.sdk.transforms.windowing.GlobalWindow (assigned by windowing)

If anyone wants to pick this up and wordsmith it more, strip some of the namespaces (where reasonable), etc, that would be great.

Issue Links

• links to: GitHub Pull Request #3857