Add dedicated "reviewers" storage to Differential and do double writes

Summary:
Ref T10967. This is an incremental step toward removing "reviewers" back to a dedicated storage table so we can handle changes like T11050.

This adds the storage table, and starts doing double writes to it (so new or updated reviewers write to both the old edge table and the new "reviewers" table).

Then we can do a migration, swap readers over one at a time, and eventually remove the old write and old storage and then implement new features.

This change has no user-facing impact, it just causes us to write new data to two places instead of one.

This is not completely exhaustive: the Herald "Add Reviewers" action is still doing a manual EDGE transaction. I'll clean that up next and do another pass to look for anything else I missed.

This is also a bit copy/pastey for now but the logic around "RESIGN" is a little different in the two cases until T11050. I'll unify it in future changes.

Test Plan:
  - Did a no-op edit.
  - Did a no-op comment.
  - Added reviewers.
  - Removed reviewers.
  - Accepted and rejected revisions.

After all of these edits, did a `SELECT * FROM differential_reviewer` manually and saw consistent-looking rows in the database.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10967

Differential Revision: https://secure.phabricator.com/D17495

resources/sql/autopatches/20170313.reviewers.01.sql

@@ -0,0 +1,9 @@
+CREATE TABLE {$NAMESPACE}_differential.differential_reviewer (
+  id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
+  revisionPHID VARBINARY(64) NOT NULL,
+  reviewerPHID VARBINARY(64) NOT NULL,
+  reviewerStatus VARCHAR(64) NOT NULL COLLATE {$COLLATE_TEXT},
+  dateCreated INT UNSIGNED NOT NULL,
+  dateModified INT UNSIGNED NOT NULL,
+  UNIQUE KEY `key_revision` (revisionPHID, reviewerPHID)
+) ENGINE=InnoDB, COLLATE {$COLLATE_TEXT};

src/__phutil_library_map__.php

@@ -491,6 +491,7 @@ phutil_register_library_map(array(
     'DifferentialRevertPlanCommitMessageField' => 'applications/differential/field/DifferentialRevertPlanCommitMessageField.php',
     'DifferentialRevertPlanField' => 'applications/differential/customfield/DifferentialRevertPlanField.php',
     'DifferentialReviewedByCommitMessageField' => 'applications/differential/field/DifferentialReviewedByCommitMessageField.php',
+    'DifferentialReviewer' => 'applications/differential/storage/DifferentialReviewer.php',
     'DifferentialReviewerDatasource' => 'applications/differential/typeahead/DifferentialReviewerDatasource.php',
     'DifferentialReviewerForRevisionEdgeType' => 'applications/differential/edge/DifferentialReviewerForRevisionEdgeType.php',
     'DifferentialReviewerProxy' => 'applications/differential/storage/DifferentialReviewerProxy.php',
@@ -5247,6 +5248,7 @@ phutil_register_library_map(array(
     'DifferentialRevertPlanCommitMessageField' => 'DifferentialCommitMessageCustomField',
     'DifferentialRevertPlanField' => 'DifferentialStoredCustomField',
     'DifferentialReviewedByCommitMessageField' => 'DifferentialCommitMessageField',
+    'DifferentialReviewer' => 'DifferentialDAO',
     'DifferentialReviewerDatasource' => 'PhabricatorTypeaheadCompositeDatasource',
     'DifferentialReviewerForRevisionEdgeType' => 'PhabricatorEdgeType',
     'DifferentialReviewerProxy' => 'Phobject',

src/applications/differential/storage/DifferentialReviewer.php

@@ -0,0 +1,24 @@
+<?php
+
+final class DifferentialReviewer
+  extends DifferentialDAO {
+
+  protected $revisionPHID;
+  protected $reviewerPHID;
+  protected $reviewerStatus;
+
+  protected function getConfiguration() {
+    return array(
+      self::CONFIG_COLUMN_SCHEMA => array(
+        'reviewerStatus' => 'text64',
+      ),
+      self::CONFIG_KEY_SCHEMA => array(
+        'key_revision' => array(
+          'columns' => array('revisionPHID', 'reviewerPHID'),
+          'unique' => true,
+        ),
+      ),
+    ) + parent::getConfiguration();
+  }
+
+}

src/applications/differential/xaction/DifferentialRevisionReviewTransaction.php

@@ -116,6 +116,9 @@ abstract class DifferentialRevisionReviewTransaction
       );
     }
 
+    // This is currently double-writing: to the old (edge) store and the new
+    // (reviewer) store. Do the old edge write first.
+
     $src_phid = $revision->getPHID();
     $edge_type = DifferentialRevisionHasReviewerEdgeType::EDGECONST;
 
@@ -131,6 +134,42 @@ abstract class DifferentialRevisionReviewTransaction
     }
 
     $editor->save();
+
+    // Now, do the new write.
+
+    if ($map) {
+      $table = new DifferentialReviewer();
+
+      $reviewers = $table->loadAllWhere(
+        'revisionPHID = %s AND reviewerPHID IN (%Ls)',
+        $src_phid,
+        array_keys($map));
+      $reviewers = mpull($reviewers, null, 'getReviewerPHID');
+
+      foreach ($map as $dst_phid => $edge_data) {
+        $reviewer = idx($reviewers, $dst_phid);
+        if (!$reviewer) {
+          $reviewer = id(new DifferentialReviewer())
+            ->setRevisionPHID($src_phid)
+            ->setReviewerPHID($dst_phid);
+        }
+
+        $reviewer->setReviewerStatus($status);
+
+        if ($status == DifferentialReviewerStatus::STATUS_RESIGNED) {
+          if ($reviewer->getID()) {
+            $reviewer->delete();
+          }
+        } else {
+          try {
+            $reviewer->save();
+          } catch (AphrontDuplicateKeyQueryException $ex) {
+            // At least for now, just ignore it if we lost a race.
+          }
+        }
+      }
+    }
+
   }
 
 }

src/applications/differential/xaction/DifferentialRevisionReviewersTransaction.php

@@ -106,6 +106,9 @@ final class DifferentialRevisionReviewersTransaction
   public function applyExternalEffects($object, $value) {
     $src_phid = $object->getPHID();
 
+    // This is currently double-writing: to the old (edge) store and the new
+    // (reviewer) store. Do the old edge write first.
+
     $old = $this->generateOldValue($object);
     $new = $value;
     $edge_type = DifferentialRevisionHasReviewerEdgeType::EDGECONST;
@@ -138,6 +141,51 @@ final class DifferentialRevisionReviewersTransaction
     }
 
     $editor->save();
+
+    // Now, do the new write.
+
+    $table = new DifferentialReviewer();
+    $table_name = $table->getTableName();
+    $conn = $table->establishConnection('w');
+
+    if ($rem) {
+      queryfx(
+        $conn,
+        'DELETE FROM %T WHERE revisionPHID = %s AND reviewerPHID IN (%Ls)',
+        $table_name,
+        $src_phid,
+        array_keys($rem));
+    }
+
+    if ($new) {
+      $reviewers = $table->loadAllWhere(
+        'revisionPHID = %s AND reviewerPHID IN (%Ls)',
+        $src_phid,
+        array_keys($new));
+      $reviewers = mpull($reviewers, null, 'getReviewerPHID');
+
+      foreach ($new as $dst_phid => $status) {
+        $old_status = idx($old, $dst_phid);
+        if ($old_status === $status) {
+          continue;
+        }
+
+        $reviewer = idx($reviewers, $dst_phid);
+        if (!$reviewer) {
+          $reviewer = id(new DifferentialReviewer())
+            ->setRevisionPHID($src_phid)
+            ->setReviewerPHID($dst_phid);
+        }
+
+        $reviewer->setReviewerStatus($status);
+
+        try {
+          $reviewer->save();
+        } catch (AphrontDuplicateKeyQueryException $ex) {
+          // At least for now, just ignore it if we lost a race.
+        }
+      }
+    }
   }
 
   public function getTitle() {