Investigation: e4xmi refactoring issue requires fix in eclipse.jdt.ui repository

[Copilot]

Issue Summary

This PR documents the investigation of issue #1169: "[e4][editor] refactoring produces garbage in fragment.e4xmi"

Investigation Findings

After extensive investigation of the eclipse.platform.ui repository, I've determined that this issue cannot be fixed in this repository. The problem requires changes in the eclipse.jdt.ui repository instead.

Root Cause

When refactoring Java class names in Eclipse, JDT's rename refactoring updates references in e4xmi files. However, it appears to use simple text search-and-replace without understanding the structure of bundleclass URIs or inner class references.

For example, when renaming a class MyPart to NewPart, the following e4xmi entries exist:

<element contributionURI="bundleclass://my.bundle/com.example.MyPart"/>
<handler contributionURI="bundleclass://my.bundle/com.example.MyPart$MyHandler"/>

The text-based replacement can produce "garbage" results because:

1. It doesn't understand that MyPart$MyHandler is an inner class reference
2. Multiple occurrences of the class name in the same file can lead to incorrect replacements
3. The bundleclass URI structure bundleclass://bundle/fully.qualified.ClassName requires special handling

Evidence from Investigation

1. No e4-aware rename participant exists in platform.ui: Searched the entire codebase for any code that updates e4xmi files during refactoring - none found
2. JDT owns Java refactoring: The rename participant that handles Java type renames is in eclipse.jdt.ui, not eclipse.platform.ui
3. Similar patterns exist: Found NLSAccessorFieldRenameParticipant in JDT that handles NLS field renames, indicating the pattern to follow

Required Solution

The fix needs to be implemented in eclipse.jdt.ui by creating a rename participant that:

• Parses bundleclass URIs correctly (bundleclass://bundle.name/fully.qualified.ClassName)
• Handles inner class references (e.g., ClassName$InnerClass)
• Updates only the appropriate parts of the class name
• Validates that replacements maintain valid bundleclass URI syntax

Repository Context

This PR is being closed as the work cannot be completed in eclipse.platform.ui. A new issue should be opened in the eclipse.jdt.ui repository to implement the required rename participant.

References

• Issue [e4][editor] refactoring produces garbage in fragment.e4xmi #1169
• bundleclass URI format: bundleclass://symbolic.bundle.name/fully.qualified.ClassName
• Related file: bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/URIHelper.java

Original prompt

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This section details on the original issue you should resolve

<issue_title>[e4][editor] refactoring produces garbage in fragment.e4xmi</issue_title>
<issue_description>If I have a class (e.g. in a shared class) in fragment.e4xmi and refactor the classname this results in a wild mixture of old and new name somewhere in the middle.

This seem to happen mostly if more than one reference is in the fragment.e4xmi, e.g. if I have MyPart and a Handler that is an inner class (e.g.MyPart$MyHandler) in a toolbar.
</issue_description>

<agent_instructions>This is likely somewhere in the refactoring participant of e4</agent_instructions>

Comments on the Issue (you are @copilot in this section)

Fixes #1169

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[laeubi]

Need to check if refactoring of e4 actually happen in platform repository :-\