Support plugin_customization.ini for e4.ui.workbench.renderer.swt prefs

[soethoff]

Before this change, only the InstanceScope was queried explicitly.

Therefore, any preferences set in 'plugin_customization.ini', which end up in the DefaultScope, were never respected.

Ideally, we would use org.eclipse.ui.preferences.ScopedPreferenceStore, but that lies in a layer above us, so cannot be used.

Instead, we use the
org.eclipse.core.runtime.preferences.IPreferencesService when reading preferences. This searches all relevant scopes in the proper order.

When writing preferences, we write explicitly into InstanceScope.

When performing 'Restore Defaults' in the preference page, we take the DefaultScope into account.

Fixes #1794.

[github-actions]

Test Results

   918 files  +    1     918 suites  +1   1h 11m 20s ⏱️ + 32m 38s
 7 510 tests ±    0   7 356 ✅  -     1  151 💤 ±  0  3 ❌ +1 
23 679 runs  +1 573  23 171 ✅ +1 453  505 💤 +119  3 ❌ +1 

For more details on these failures, see this check.

Results for commit f5a282c. ± Comparison against base commit 8f59241.

[BeckerWdf]

How can I test this with a Run Configuration? So I mean I want to start a target IDE from my workspace (that includes this PR). How do I set the preference value in the run configuration?

[soethoff]

How can I test this with a Run Configuration? So I mean I want to start a target IDE from my workspace (that includes this PR). How do I set the preference value in the run configuration?

Create a 'plugin_customization.ini' and add one or more settings you want to set as new default, e.g.: org.eclipse.e4.ui.workbench.renderers.swt/SHOW_FULL_TEXT_FOR_VIEW_TABS=true

In your run configuration add the created 'plugin_customization.ini' as 'Program argument':

-pluginCustomization 
<path/to/your/plugin_customization.ini>

Note: The option 'Clear the configuration area before launching' should be enabled

[BeckerWdf]

How can I test this with a Run Configuration? So I mean I want to start a target IDE from my workspace (that includes this PR). How do I set the preference value in the run configuration?

Create a 'plugin_customization.ini' and add one or more settings you want to set as new default, e.g.: org.eclipse.e4.ui.workbench.renderers.swt/SHOW_FULL_TEXT_FOR_VIEW_TABS=true

In your run configuration add the created 'plugin_customization.ini' as 'Program argument':

-pluginCustomization 
<path/to/your/plugin_customization.ini>

Note: The option 'Clear the configuration area before launching' should be enabled

That worked. Thanks. It also worked without the "Clear" option.
From my point of view this PR looks good.

[BeckerWdf]

Failed test are know and already reported:
#275
#1807
#195

[fedejeanne]

Failed test are know and already reported: #275 #1427 #195

1427 was not correct, the stack traces are different. I edited the comment to avoid confusions