Make sure linked preferences remain in-sync after external file change by ptziegler · Pull Request #2914 · eclipse-platform/eclipse.platform

ptziegler · 2026-09-08T20:49:17Z

When a preference file is changed by an external process (e.g. a Git update), it may happen that the preference node for projects that link to this file are not updated properly. Those projects will then continue working with outdated preferences, until either the application is restarted or the preference file is manually updated.

ptziegler · 2026-09-08T20:51:40Z

Here's a short video demonstrating the problem. When restoring the original preferences by clicking on "Replace with HEAD revision", I would expect the project scope of the project with those linked preferences to also update. This doesn't happen and instead it's stuck with the outdated scope.

Screencast_20260908_224550.webm

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🟡 Changes recommended

Reverse alias refresh remains incomplete, and the external-change test may be flaky due to timestamp granularity.

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Pull request overview

Updates project preference synchronization when linked preference files change externally.

Changes:

Refreshes metadata for changed linked files.
Adds linked-project preference synchronization tests.

File summaries

File	Description
`RefreshLocalVisitor.java`	Reloads metadata for changed linked files.
`ProjectPreferencesTest.java`	Tests linked preference synchronization paths.

Review details

Files reviewed: 2/2 changed files
Comments generated: 2
Review effort level: Balanced

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Copilot

🟡 Changes recommended

The new test must create project2’s .settings parent folder before creating the link.

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Review details

Files reviewed: 2/2 changed files
Comments generated: 1
Review effort level: Balanced

ptziegler · 2026-09-08T21:36:43Z

+
+		IFile prefFile1 = getFileInWorkspace(project1, nodeName);
+		IFile prefFile2 = getFileInWorkspace(project2, nodeName);
+		prefFile2.createLink(prefFile1.getLocationURI(), IResource.ALLOW_MISSING_LOCAL, createTestMonitor());


That is not true. When project2 is created, the Platform automatically creates the .settings/org.eclipse.core.resources.prefs file. So the settings folder will always exist, which is also the reason why no error is thrown when executing the test without this change.

github-actions · 2026-09-08T22:15:52Z

Test Results

45 files - 9 45 suites - 9 55m 37s ⏱️ - 3m 32s
4 550 tests - 217 4 527 ✅ - 218 22 💤 ±0 1 ❌ +1
11 541 runs - 651 11 385 ✅ - 654 153 💤 ±0 3 ❌ +3

For more details on these failures, see this check.

Results for commit 67e12fd. ± Comparison against base commit e9ab4bb.

This pull request removes 220 and adds 3 tests. Note that renamed tests count towards both.

org.eclipse.compare.tests.AsyncExecTests ‑ testCancelOnRequeue
org.eclipse.compare.tests.AsyncExecTests ‑ testQueueAdd
org.eclipse.compare.tests.AsyncExecTests ‑ testWorker
org.eclipse.compare.tests.CompareFileRevisionEditorInputTest ‑ testPrepareCompareInputWithNonLocalResourceTypedElements
org.eclipse.compare.tests.CompareOpenEfficiencyTest ‑ testBinaryContentsAreNotReadAhead
org.eclipse.compare.tests.CompareOpenEfficiencyTest ‑ testGetContentsCallCountPerSide
org.eclipse.compare.tests.CompareOpenEfficiencyTest ‑ testPrepareInputOffUiThreadUnifiedOff
org.eclipse.compare.tests.CompareOpenEfficiencyTest ‑ testPrepareInputOffUiThreadUnifiedOn
org.eclipse.compare.tests.CompareOpenEfficiencyTest ‑ testPrepareInputRunsOnceUnifiedOff
org.eclipse.compare.tests.CompareOpenEfficiencyTest ‑ testPrepareInputRunsOnceUnifiedOn
…

org.eclipse.core.tests.internal.resources.ProjectPreferencesTest ‑ testLinkedProjectPreferences
org.eclipse.core.tests.internal.resources.ProjectPreferencesTest ‑ testLinkedProjectPreferencesFolder
org.eclipse.core.tests.internal.resources.ProjectPreferencesTest ‑ testSymLinkedProjectPreferences

♻️ This comment has been updated with latest results.

merks · 2026-09-09T05:27:17Z

I wonder about the general handling of the tree under a linked folder. E.g., if one linked the .settings folder, would that have similar/different problems with respect the the IDE seeing the preference changes?

ptziegler · 2026-09-09T07:04:48Z

E.g., if one linked the .settings folder, would that have similar/different problems with respect the the IDE seeing the preference changes?

AFAIK, you can only link files, not folders. You even get a funny error message when trying to do so,

When trying to use the "New" wizard, you get a similar error:

iloveeclipse · 2026-09-09T07:13:48Z

AFAIK, you can only link files, not folders.

Of course links are not restricted to files, just try to use "new folder" wizard :-)

iloveeclipse · 2026-09-09T07:15:35Z

if one linked the .settings folder, would that have similar/different problems with respect the the IDE seeing the preference changes?

One can check, with real FS links it works for sure, probably also should work with "virtual", we link .settings since years on Linux.

merks · 2026-09-09T07:26:36Z

It seems to offer it, which is why I asked...

ptziegler · 2026-09-09T07:40:34Z

Of course links are not restricted to files, just try to use "new folder" wizard :-)

Good point, I missed that it's a different wizard.

After a quick test I can tell that when the folder is linked and the preference file is changed, the test is still successful, regardless of whether the refresh is done on the file or the folder (and also fails without the change). Which I don't think is really surprising, because when a folder is linked, the containing files are obviously also linked. The only relevant part is that a resource-changed event is fired for the file.

Though I'll try to write a dedicated test for that once I'm back at my PC.

One can check, with real FS links it works for sure, probably also should work with "virtual", we link .settings since years on Linux.

I don't have any way of testing that.

ptziegler · 2026-09-09T17:03:03Z

I've added an additional test case to also check the correctness when linking folders. Regarding virtual file systems: As said before, I don't have any means of testing this. But conceptually, the only requirement is that resource-change events are fired correctly.

iloveeclipse · 2026-09-09T17:30:30Z

Regarding virtual file systems

I probably was not clear enough in my previous comment. Links you were fixing/testing here are "Eclipse-only", thus "virtual", compared with real file system links.

ptziegler · 2026-09-09T19:25:50Z

I probably was not clear enough in my previous comment. Links you were fixing/testing here are "Eclipse-only", thus "virtual", compared with real file system links.

Ah, you meant physical and symbolic links. Yes, those won't work (yet) because they aren't tracked by the alias-manager. I've added a new test case which covers this configuration as well, but which will fail.

When a preference file is changed by an external process (e.g. a Git update), it may happen that the preference node for projects that link to this file are not updated properly. Those projects will then continue working with outdated preferences, until either the application is restarted or the preference file is manually updated.

ptziegler · 2026-09-09T19:50:51Z

those won't work (yet) because they aren't tracked by the alias-manager

Bug 198291 - AliasManager should track symlinks

iloveeclipse requested a balanced review from Copilot September 8, 2026 20:51

Copilot started reviewing on behalf of iloveeclipse September 8, 2026 20:51 View session

ptziegler mentioned this pull request Sep 8, 2026

Move PDE/JDT prefs to ".eclipse" project and reference by resource link eclipse-gef/gef-classic#1182

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Copilot AI reviewed Sep 8, 2026

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Comment thread ...org.eclipse.core.resources/src/org/eclipse/core/internal/localstore/RefreshLocalVisitor.java Outdated

Comment thread ...re.tests.resources/src/org/eclipse/core/tests/internal/resources/ProjectPreferencesTest.java

ptziegler force-pushed the linked-preference-scope branch from 7092e38 to ff9ec1e Compare September 8, 2026 21:17

iloveeclipse requested a balanced review from Copilot September 8, 2026 21:26

Copilot started reviewing on behalf of iloveeclipse September 8, 2026 21:27 View session

Copilot AI reviewed Sep 8, 2026

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ptziegler force-pushed the linked-preference-scope branch from ff9ec1e to a34a529 Compare September 9, 2026 04:42

ptziegler force-pushed the linked-preference-scope branch from a34a529 to 14bcc05 Compare September 9, 2026 16:59

ptziegler force-pushed the linked-preference-scope branch from 14bcc05 to 965873b Compare September 9, 2026 19:24

ptziegler force-pushed the linked-preference-scope branch from 965873b to 67e12fd Compare September 9, 2026 19:26

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