[Feature Request]: improve stream consistency checks

[liosc]

What would you like to happen?

When developing a pipeline with converging streams I find useful deleting an hop and re-creating it to check if the streams are identical in case I changed something in one or both. It's a fast and useful test to check your work without having to run the pipeline. Re-creating the hop triggers the checks about number of fields, field names and types. It would be useful to have a re-creation option in the window that appears clicking on an hop. Another option could be having in the same window an icon to trigger the validations, something like "Check streams consistency".

Issue Priority

Priority: 3

Issue Component

Component: Hop Gui

[mattcasters]

A good idea. I'll add a context action on the merging transform "Layout Check".
We should get detailed feedback and also offer the end-user to replace a Dummy merging streams with a Stream Schema Merge transform

[mattcasters]

Walkthrough - Layout Check Context Action

We added a new context action on pipeline transforms called Layout Check which validates that the row layouts of all previous input transforms are identical. We also added support to offer replacing the transform with a Stream Schema Merge transform if it is a Dummy transform.

Changes Made

Hop GUI

• Modified HopGuiPipelineGraph.java to implement the layoutCheck(HopGuiPipelineTransformContext context) method annotated with @GuiContextAction.
• Implemented checkLayoutOfTransformInput in HopGuiPipelineHopDelegate.java:
  • The validation retrieves the row layouts of all previous input transforms and compares them field-by-field.
  • On mismatch, it lists all fields for each input and highlights details of differences (mismatched name, mismatched type, missing fields) in a read-only, fixed-font EnterTextDialog.
  • If the checked transform is a Dummy transform, the action prompts the user using a MessageBox offering to replace it with a Stream Schema Merge transform, swap it in place preserving coordinates and hops, and registers an undo step.
  • Configures the instantiated StreamSchemaMeta's transformsToMerge list with the names of the previous transforms using Java reflection (with Class.forName using streamSchemaMeta's classloader) to avoid compile-time dependencies on the plugin.
• Refactored checkLayoutOfTransformInput to use BaseMessages.getString(PKG, "key") for all user-facing strings and placeholders, storing all localization keys in messages_en_US.properties.
• Replaced the generic ErrorDialog call in the HopRowException catch block inside performNewPipelineHopChecks in HopGuiPipelineHopDelegate.java with a call to the new layout checker checkLayoutOfTransformInput.

Verification & Testing

Compilation & Tests

• Cleanly compiled both engine and ui modules successfully:

  ./mvnw test-compile -pl engine,ui

• Checked code formatting with spotless:

  ./mvnw spotless:check -pl ui

• Executed unit tests for ui and projects modules, with all passing:

  ./mvnw test -pl ui
  ./mvnw test -pl plugins/misc/projects