Bug 1920419 - Fix what happens if an *.oauth2.scope pref is empty. r=mkmelin

Differential Revision: https://phabricator.services.mozilla.com/D223251

--HG--
extra : rebase_source : 5cf4f446f51d7d4226fedde55143413ecbdc516e

mailnews/base/src/OAuth2Module.sys.mjs

@@ -73,7 +73,9 @@ OAuth2Module.prototype = {
     const details = OAuth2Providers.getHostnameDetails(aHostname);
     if (
       details &&
-      (details[0] != issuer || !scopeSet(details[1]).isSupersetOf(prefScopes))
+      (details[0] != issuer ||
+        !scope ||
+        !scopeSet(details[1]).isSupersetOf(prefScopes))
     ) {
       if (details[0] != issuer) {
         log.info(
@@ -82,7 +84,7 @@ OAuth2Module.prototype = {
       }
       if (!scopeSet(details[1]).isSupersetOf(prefScopes)) {
         log.info(
-          `${root}oauth2.scope "${scope}" is not a superset of "${details[1]}"`
+          `${root}oauth2.scope "${scope}" is not a subset of "${details[1]}"`
         );
       }
       // Found in the list of hardcoded providers. Use the hardcoded values.