Fix two Passphrase credential type issues

Summary:
Fixes T4991. Two issues:

  - These error messages pass an object to "%s", when they mean to pass a type constant.
  - The check for noncreatable credentials is incorrectly in the "edit" branch of the controller.

Test Plan:
  - Edited a "SSH Key on disk" credential.
  - Tried to create a credential with a bogus type.

Reviewers: btrahan, joshuaspence

Reviewed By: joshuaspence

Subscribers: epriestley

Maniphest Tasks: T4991

Differential Revision: https://secure.phabricator.com/D9299

Author: epriestley

src/applications/passphrase/controller/PassphraseCredentialEditController.php

@@ -26,23 +26,18 @@ public function processRequest() {
         return new Aphront404Response();
       }
 
-      $type = PassphraseCredentialType::getTypeByConstant(
-        $credential->getCredentialType());
-      if (!$type) {
-        throw new Exception(pht('Credential has invalid type "%s"!', $type));
-      }
-
-      if (!$type->isCreateable()) {
-        throw new Exception(
-          pht('Credential has noncreateable type "%s"!', $type));
-      }
+      $type = $this->getCredentialType($credential->getCredentialType());
 
       $is_new = false;
     } else {
       $type_const = $request->getStr('type');
-      $type = PassphraseCredentialType::getTypeByConstant($type_const);
-      if (!$type) {
-        return new Aphront404Response();
+      $type = $this->getCredentialType($type_const);
+
+      if (!$type->isCreateable()) {
+        throw new Exception(
+          pht(
+            'Credential has noncreateable type "%s"!',
+            $credential->getCredentialType()));
       }
 
       $credential = PassphraseCredential::initializeNewCredential($viewer)
@@ -358,4 +353,15 @@ public function processRequest() {
       ));
   }
 
+  private function getCredentialType($type_const) {
+    $type = PassphraseCredentialType::getTypeByConstant($type_const);
+
+    if (!$type) {
+      throw new Exception(
+        pht('Credential has invalid type "%s"!', $type_const));
+    }
+
+    return $type;
+  }
+
 }