Change default scope for PreferenceService.set

Signed-off-by: Colin Grant <colin.grant@ericsson.com>

packages/core/src/browser/preferences/preference-service.ts

@@ -149,6 +149,7 @@ export interface PreferenceService extends Disposable {
      * @param value the new value of the preference.
      * @param scope the scope for which the value shall be set, i.e. user, workspace etc.
      * When the folder scope is specified a resourceUri must be provided.
+     * Defaults to folder scope if resourceUri is provided, user scope otherwise.
      * @param resourceUri the uri of the resource for which the preference is stored. This used to store
      * a potentially different value for the same preference for different resources, for example `files.encoding`.
      *
@@ -401,9 +402,9 @@ export class PreferenceServiceImpl implements PreferenceService {
     }
 
     async set(preferenceName: string, value: any, scope: PreferenceScope | undefined, resourceUri?: string): Promise<void> {
-        const resolvedScope = scope !== undefined ? scope : (!resourceUri ? PreferenceScope.Workspace : PreferenceScope.Folder);
-        if (resolvedScope === PreferenceScope.User && this.configurations.isSectionName(preferenceName.split('.', 1)[0])) {
-            throw new Error(`Unable to write to User Settings because ${preferenceName} does not support for global scope.`);
+        const resolvedScope = scope ?? (resourceUri ? PreferenceScope.Folder : PreferenceScope.User);
+        if (!this.schema.isValidInScope(preferenceName, resolvedScope)) {
+            throw new Error(`Unable to write to ${PreferenceScope[resolvedScope]} scope because ${preferenceName} is not supported in that scope.`);
         }
         if (resolvedScope === PreferenceScope.Folder && !resourceUri) {
             throw new Error('Unable to write to Folder Settings because no resource is provided.');