Bug 1665281 - Follow-up, always check subkeys, even if primary key is usable. r=PatrickBrunschwig DONTBUILD

Differential Revision: https://phabricator.services.mozilla.com/D91581

--HG--
extra : amend_source : b28e0151f7117d1d02f2a031172c5897f26206af

mail/extensions/openpgp/content/modules/RNP.jsm

@@ -1963,16 +1963,13 @@ var RNP = {
   },
 
   addSuitableEncryptKey(key, op) {
-    let use_sub = null;
+    // Prefer usable subkeys, because they are always newer
+    // (or same age) as primary key.
 
-    // looks like this will be unnecessary ???
-
-    if (!this.isKeyUsableFor(key, str_encrypt)) {
-      use_sub = this.getSuitableSubkey(key, str_encrypt);
-      if (!use_sub) {
+    let use_sub = this.getSuitableSubkey(key, str_encrypt);
+    if (!use_sub && !this.isKeyUsableFor(key, str_encrypt)) {
       throw new Error("no suitable subkey found for " + str_encrypt);
     }
-    }
 
     if (
       RNPLib.rnp_op_encrypt_add_recipient(op, use_sub != null ? use_sub : key)
@@ -2101,13 +2098,14 @@ var RNP = {
         this.addSuitableEncryptKey(senderKey, op);
       }
       if (args.sign) {
-        let use_sub = null;
-        if (!this.isKeyUsableFor(senderKey, str_sign)) {
-          use_sub = this.getSuitableSubkey(senderKey, str_sign);
-          if (!use_sub) {
+        // Prefer usable subkeys, because they are always newer
+        // (or same age) as primary key.
+
+        let use_sub = this.getSuitableSubkey(senderKey, str_sign);
+        if (!use_sub && !this.isKeyUsableFor(senderKey, str_sign)) {
           throw new Error("no suitable subkey found for " + str_sign);
         }
-        }
+
         if (args.encrypt) {
           if (
             RNPLib.rnp_op_encrypt_add_signature(