Allow custom actions in Differential to explicitly override "accept" stickiness

Summary:
See PHI431. Ref T13102. An install is interested in a custom "non-sticky" accept action, roughly.

On the one hand, this is a pretty hacky patch. However, I suspect it inches us closer to T731, and I'm generally comfortable with exploring the realms of "Accept Next Update", "Unblock Without Accepting", etc., as long as most of it doesn't end up enabled by default in the upstream.

Test Plan:
  - Accepted and updated revisions normally, saw accepts respect global stickiness.
  - Modified the "Accept" action to explicitly be unsticky, saw nonsticky accept behavior after update.

Maniphest Tasks: T13102

Differential Revision: https://secure.phabricator.com/D19211

resources/sql/autopatches/20180312.reviewers.01.options.sql

@@ -0,0 +1,2 @@
+ALTER TABLE {$NAMESPACE}_differential.differential_reviewer
+  ADD options LONGTEXT NOT NULL COLLATE {$COLLATE_TEXT};

resources/sql/autopatches/20180312.reviewers.02.optionsdefault.sql

@@ -0,0 +1,2 @@
+UPDATE {$NAMESPACE}_differential.differential_reviewer
+  SET options = '{}' WHERE options = '';

src/applications/differential/editor/DifferentialTransactionEditor.php

@@ -154,59 +154,41 @@ final class DifferentialTransactionEditor
 
     $edge_ref_task = DifferentialRevisionHasTaskEdgeType::EDGECONST;
 
-    $is_sticky_accept = PhabricatorEnv::getEnvConfig(
-      'differential.sticky-accept');
-
-    $downgrade_rejects = false;
-    $downgrade_accepts = false;
+    $want_downgrade = array();
+    $must_downgrade = array();
     if ($this->getIsCloseByCommit()) {
       // Never downgrade reviewers when we're closing a revision after a
       // commit.
     } else {
       switch ($xaction->getTransactionType()) {
         case DifferentialRevisionUpdateTransaction::TRANSACTIONTYPE:
-          $downgrade_rejects = true;
-          if (!$is_sticky_accept) {
-            // If "sticky accept" is disabled, also downgrade the accepts.
-            $downgrade_accepts = true;
-          }
+          $want_downgrade[] = DifferentialReviewerStatus::STATUS_ACCEPTED;
+          $want_downgrade[] = DifferentialReviewerStatus::STATUS_REJECTED;
           break;
         case DifferentialRevisionRequestReviewTransaction::TRANSACTIONTYPE:
-          $downgrade_rejects = true;
-          if ((!$is_sticky_accept) ||
-              (!$object->isChangePlanned())) {
-            // If the old state isn't "changes planned", downgrade the accepts.
-            // This exception allows an accepted revision to go through
-            // "Plan Changes" -> "Request Review" and return to "accepted" if
-            // the author didn't update the revision, essentially undoing the
-            // "Plan Changes".
-            $downgrade_accepts = true;
+          if (!$object->isChangePlanned()) {
+            // If the old state isn't "Changes Planned", downgrade the accepts
+            // even if they're sticky.
+
+            // We don't downgrade for "Changes Planned" to allow an author to
+            // undo a "Plan Changes" by immediately following it up with a
+            // "Request Review".
+            $want_downgrade[] = DifferentialReviewerStatus::STATUS_ACCEPTED;
+            $must_downgrade[] = DifferentialReviewerStatus::STATUS_ACCEPTED;
           }
+          $want_downgrade[] = DifferentialReviewerStatus::STATUS_REJECTED;
           break;
       }
     }
 
-    $new_accept = DifferentialReviewerStatus::STATUS_ACCEPTED;
-    $new_reject = DifferentialReviewerStatus::STATUS_REJECTED;
-    $old_accept = DifferentialReviewerStatus::STATUS_ACCEPTED_OLDER;
-    $old_reject = DifferentialReviewerStatus::STATUS_REJECTED_OLDER;
-
-    $downgrade = array();
-    if ($downgrade_accepts) {
-      $downgrade[] = DifferentialReviewerStatus::STATUS_ACCEPTED;
-    }
-
-    if ($downgrade_rejects) {
-      $downgrade[] = DifferentialReviewerStatus::STATUS_REJECTED;
-    }
-
-    if ($downgrade) {
+    if ($want_downgrade) {
       $void_type = DifferentialRevisionVoidTransaction::TRANSACTIONTYPE;
 
       $results[] = id(new DifferentialTransaction())
         ->setTransactionType($void_type)
         ->setIgnoreOnNoEffect(true)
-        ->setNewValue($downgrade);
+        ->setMetadataValue('void.force', $must_downgrade)
+        ->setNewValue($want_downgrade);
     }
 
     $is_commandeer = false;

src/applications/differential/storage/DifferentialReviewer.php

@@ -10,12 +10,16 @@ final class DifferentialReviewer
   protected $lastCommentDiffPHID;
   protected $lastActorPHID;
   protected $voidedPHID;
+  protected $options = array();
 
   private $authority = array();
   private $changesets = self::ATTACHABLE;
 
   protected function getConfiguration() {
     return array(
+      self::CONFIG_SERIALIZATION => array(
+        'options' => self::SERIALIZATION_JSON,
+      ),
       self::CONFIG_COLUMN_SCHEMA => array(
         'reviewerStatus' => 'text64',
         'lastActionDiffPHID' => 'phid?',
@@ -64,6 +68,15 @@ final class DifferentialReviewer
     return $this->assertAttached($this->changesets);
   }
 
+  public function setOption($key, $value) {
+    $this->options[$key] = $value;
+    return $this;
+  }
+
+  public function getOption($key, $default = null) {
+    return idx($this->options, $key, $default);
+  }
+
   public function isResigned() {
     $status_resigned = DifferentialReviewerStatus::STATUS_RESIGNED;
     return ($this->getReviewerStatus() == $status_resigned);

src/applications/differential/xaction/DifferentialRevisionReviewTransaction.php

@@ -164,7 +164,14 @@ abstract class DifferentialRevisionReviewTransaction
     DifferentialRevision $revision,
     PhabricatorUser $viewer,
     $value,
-    $status) {
+    $status,
+    array $reviewer_options = array()) {
+
+    PhutilTypeSpec::checkMap(
+      $reviewer_options,
+      array(
+        'sticky' => 'optional bool',
+      ));
 
     $map = array();
 
@@ -253,6 +260,8 @@ abstract class DifferentialRevisionReviewTransaction
         // accepted.
         $reviewer->setVoidedPHID(null);
 
+        $reviewer->setOption('sticky', idx($reviewer_options, 'sticky'));
+
         try {
           $reviewer->save();
         } catch (AphrontDuplicateKeyQueryException $ex) {

src/applications/differential/xaction/DifferentialRevisionVoidTransaction.php

@@ -16,21 +16,43 @@ final class DifferentialRevisionVoidTransaction
   }
 
   public function generateNewValue($object, $value) {
-    $table = new DifferentialReviewer();
-    $table_name = $table->getTableName();
-    $conn = $table->establishConnection('w');
-
-    $rows = queryfx_all(
-      $conn,
-      'SELECT reviewerPHID FROM %T
-        WHERE revisionPHID = %s
+    $reviewers = id(new DifferentialReviewer())->loadAllWhere(
+      'revisionPHID = %s
         AND voidedPHID IS NULL
         AND reviewerStatus IN (%Ls)',
-      $table_name,
       $object->getPHID(),
       $value);
 
-    return ipull($rows, 'reviewerPHID');
+    $must_downgrade = $this->getMetadataValue('void.force', array());
+    $must_downgrade = array_fuse($must_downgrade);
+
+    $default = PhabricatorEnv::getEnvConfig('differential.sticky-accept');
+    foreach ($reviewers as $key => $reviewer) {
+      $status = $reviewer->getReviewerStatus();
+
+      // If this void is forced, always downgrade. For example, this happens
+      // when an author chooses "Request Review": existing reviews are always
+      // voided, even if they're sticky.
+      if (isset($must_downgrade[$status])) {
+        continue;
+      }
+
+      // Otherwise, if this is a sticky accept, don't void it. Accepts may be
+      // explicitly sticky or unsticky, or they'll use the default value if
+      // no value is specified.
+      $is_sticky = $reviewer->getOption('sticky');
+      $is_sticky = coalesce($is_sticky, $default);
+
+      if ($status === DifferentialReviewerStatus::STATUS_ACCEPTED) {
+        if ($is_sticky) {
+          unset($reviewers[$key]);
+          continue;
+        }
+      }
+    }
+
+
+    return mpull($reviewers, 'getReviewerPHID');
   }
 
   public function getTransactionHasEffect($object, $old, $new) {