Prevent Target Editor reverts for marker-only resource changes

[vlakn]

Summary

The issue first surfaced with the m2e PDE integration, which triggers marker updates while editing a .target definition. These marker updates cause TargetEditor to revert the editor, discarding unsaved source-page input.

The behavior is not specific to m2e. Creating a bookmark on the open .target file also produces a marker-only resource delta and triggers the same revert.

For example, enter any unsaved XML change in the source page and then create a bookmark on the .target file. The Target Editor discards the working copy although the file content remains unchanged.

This change prevents the Target Editor from reverting unsaved source-page edits when the workspace reports a marker-only change for the opened .target file.

Background

Commit 68642a1 extended TargetEditor.doRevert() to also revert dirty text-editor pages.

TargetEditor.InputHandler.resourceChanged() currently invokes doRevert() for every IResourceDelta.CHANGED delta on the target file. This includes marker-only deltas, although they do not alter the target definition content.

With the m2e PDE integration installed, workspace refreshes and marker updates trigger such deltas. While editing the XML source page, typing a character such as < then discards the unsaved working copy.

Before

After

[merks]

That looks like a nice simple change to fix behavior that drives me crazy. 😕

[vogella]

Ah, that is that? Drove me also crazy, I always assumed that it is the XML language server.

[merks]

Ignore the license failure, it's been flaky again:

Received an error response from the Eclipse Foundation

[vogella]

Big thanks @vlakn for this fix

[github-actions]

Test Results

  129 files  ±0    129 suites  ±0   37m 7s ⏱️ -13s
3 531 tests ±0  3 477 ✅ +40   54 💤 ±0  0 ❌  - 40 
9 396 runs  ±0  9 266 ✅ +40  130 💤 ±0  0 ❌  - 40 

Results for commit e06b3b5. ± Comparison against base commit b5aa639.

[HeikoKlare]

I did some manuel testing of the change (in particular that marker/bookmark changes do not revert changes of the editor content) and found everything to work fine so far.

Awesome to have this fixed. Thank you, @vlakn!

[merks]

FYI, I manually test this in a self-hosted launch, first reproducing the problem (with the language server stuff in the target platform), then applying the patch to verify that the reverts don't happen, and then also verifying that if I edit the file via a different editor and save, the revert does happen.

So this looks great! 🏆 🏅