Projects - add "lock membership", which prevents people from leaving

Summary:
Fixes T5603. Puts the toggling of locking membership into the editor so we get exceptions and all that.

I think the dialogue when you try to leave a project that is locked could be a little better maybe? Right now it just says "You can't leave" and "The membership is locked" more or less; should I surface a link to the policy stuff there too?

Test Plan:
 - made a project, toggled the "lock" setting, observed stickiness and good transactions being made
 - locked a project and tried to leave as a non-editor - got a dialogue letting me know i couldn't
 - locked a project and tried to leave as an editor - left successfully

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Maniphest Tasks: T5603

Differential Revision: https://secure.phabricator.com/D10508

src/applications/project/controller/PhabricatorProjectEditDetailsController.php

@@ -49,6 +49,7 @@ final class PhabricatorProjectEditDetailsController
     $v_slugs = $project_slugs;
     $v_color = $project->getColor();
     $v_icon = $project->getIcon();
+    $v_locked = $project->getIsMembershipLocked();
 
     $validation_exception = null;
 
@@ -63,6 +64,7 @@ final class PhabricatorProjectEditDetailsController
       $v_join = $request->getStr('can_join');
       $v_color = $request->getStr('color');
       $v_icon = $request->getStr('icon');
+      $v_locked = $request->getInt('is_membership_locked', 0);
 
       $xactions = $field_list->buildFieldTransactionsFromRequest(
         new PhabricatorProjectTransaction(),
@@ -73,6 +75,7 @@ final class PhabricatorProjectEditDetailsController
       $type_edit = PhabricatorTransactions::TYPE_EDIT_POLICY;
       $type_icon = PhabricatorProjectTransaction::TYPE_ICON;
       $type_color = PhabricatorProjectTransaction::TYPE_COLOR;
+      $type_locked = PhabricatorProjectTransaction::TYPE_LOCKED;
 
       $xactions[] = id(new PhabricatorProjectTransaction())
         ->setTransactionType($type_name)
@@ -102,6 +105,10 @@ final class PhabricatorProjectEditDetailsController
         ->setTransactionType($type_color)
         ->setNewValue($v_color);
 
+      $xactions[] = id(new PhabricatorProjectTransaction())
+        ->setTransactionType($type_locked)
+        ->setNewValue($v_locked);
+
       $editor = id(new PhabricatorProjectTransactionEditor())
         ->setActor($viewer)
         ->setContentSourceFromRequest($request)
@@ -148,6 +155,10 @@ final class PhabricatorProjectEditDetailsController
 
     $icon_uri = $this->getApplicationURI('icon/'.$project->getID().'/');
     $icon_display = PhabricatorProjectIcon::renderIconForChooser($v_icon);
+    list($can_lock, $lock_message) = $this->explainApplicationCapability(
+      ProjectCanLockProjectsCapability::CAPABILITY,
+      pht('You can update the Lock Project setting.'),
+      pht('You can not update the Lock Project setting.'));
 
     $form
       ->appendChild(
@@ -201,6 +212,16 @@ final class PhabricatorProjectEditDetailsController
           ->setPolicyObject($project)
           ->setPolicies($policies)
           ->setCapability(PhabricatorPolicyCapability::CAN_JOIN))
+      ->appendChild(
+        id(new AphrontFormCheckboxControl())
+        ->setLabel(pht('Lock Project'))
+        ->setDisabled(!$can_lock)
+        ->addCheckbox(
+          'is_membership_locked',
+          1,
+          pht('Prevent members from leaving this project.'),
+          $v_locked)
+        ->setCaption($lock_message))
       ->appendChild(
         id(new AphrontFormSubmitControl())
           ->addCancelButton($edit_uri)