The project specific preferences are ignored and overridden by the workspace one

[kittaakos]

Steps to reproduce:

• Have a boolean preference key with false default value.
• Enabled this preference at workspace level by setting the value to true.
• Create a project, and the enable project specific preferences. Configure the preference value on the project to false.
• The project specific preference value will be true although I would expect false.

In the FixedScopedPreferenceStore.setValue(String, boolean); we remove the project-level preferences because it equals to the default one. Then later, when we are trying to get the value for the project specific preference, we invoke FixedScopedPreferenceStore.internalGet(String) which delegates to the PreferencesService.get(String, String, Preferences[]). Although we have the chain of preferences (starting with the project scoped one), we get the workspace level value because we have removed the preference entry from the project-level preferences earlier.

[kittaakos]

A very simple example can be found here.

One has to

• Clone the repo.
• Import projects.
• Run the workflow.
• Start an application.
• Create a project with a .mydsl file.
• Enable the generate-timestamp option in the preference page.
• Enable project specific preferences AND disable the generate-timestamp in the preferences.

The timestamp is being generated into the output file, although I would expect the opposite. Could be that I have messed up something in the code. I will add some tests too.

[cdietrich]

this was reported here as well: https://www.eclipse.org/forums/index.php/m/1489371/

[kittaakos]

I took some time to look into the issue again. I wanted to reproduce the same (or at least a very similar) defect by only modifying Xtend preferences in my local Eclipse environment.

By default, Xtend does not generate the @Generated annotation into the code. So I thought this preference entry would be the perfect candidate to reproduce the issue.

First, I have enabled the @Generated annotation on the workspace level by setting the preference value to true, then I've enabled the project-specific preferences and disabled the annotation generation. I've expected that although the annotation generation is disabled at the project-specific level, the annotation is going to be generated due to this defect. It did not happen.

Then I've looked into the code again. For this particular case, I was playing with, a subclass of the OptionsConfigurationBlock is being used to alter the preferences. This implementation never calls setValue but the putValue method instead. The putValue method does not remove the entry from the preference store if the new value equals to the default one. Only the setValue does that. So I've changed the code in OptionsConfigurationBlock, and instead of calling putValue, I've invoked setValue. Finally, I was able to reproduce the defect with pure Xtend preferences. That means there is a huge behavior difference between calling the putValue and the setValue.

Here is the local change I have made to break the behavior in the Xtend preference page.

diff --git a/org.eclipse.xtext.ui/src/org/eclipse/xtext/ui/preferences/OptionsConfigurationBlock.java b/org.eclipse.xtext.ui/src/org/eclipse/xtext/ui/preferences/OptionsConfigurationBlock.java
index 6d026f4..738821c 100755
--- a/org.eclipse.xtext.ui/src/org/eclipse/xtext/ui/preferences/OptionsConfigurationBlock.java
+++ b/org.eclipse.xtext.ui/src/org/eclipse/xtext/ui/preferences/OptionsConfigurationBlock.java
@@ -468,7 +468,7 @@
             return disabledProjectSettings.put(key, value);
         }
         String oldValue = getValue(key);
-        preferenceStore.putValue(key, value);
+        preferenceStore.setValue(key, value);
         return oldValue;
     }

@@ -489,7 +489,7 @@
                 for (int i = 0; i < keys.length; i++) {
                     String curr = keys[i];
                     String val = disabledProjectSettings.get(curr);
-                    preferenceStore.putValue(curr, val);
+                    preferenceStore.setValue(curr, val);
                 }
                 disabledProjectSettings = null;
                 updateControls();