Let Herald activation depend on which transactions are being applied, and generate transactions

Summary:
Ref T2222. Ref T4484. This is a stepping stone to getting Herald supported in the new Differental code. Generally:

  - Instead of an Editor either supporting or not supporting Herald, let it choose based on transactions. Specifically, Differential only runs rules on revision creation and diff updates.
  - Optionally, allow an Editor to return some transactions to apply instead of having to apply everything itself. This lets us make it clear why changes happend in the transaction log, and share more code.
  - I updated only one transaction type (owners in Maniphest) since it was the easiest and cleanest to update and test. Everything else still works like it used to, it just won't generate a transaction record yet.
  - The transaction records are a touch rough, but we can clean them up later.

Test Plan: {F122282}

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T4484, T2222

Differential Revision: https://secure.phabricator.com/D8404

src/applications/maniphest/editor/ManiphestTransactionEditor.php

@@ -317,7 +317,9 @@ final class ManiphestTransactionEditor
     return true;
   }
 
-  protected function supportsHerald() {
+  protected function shouldApplyHeraldRules(
+    PhabricatorLiskDAO $object,
+    array $xactions) {
     return true;
   }
 
@@ -334,6 +336,9 @@ final class ManiphestTransactionEditor
     HeraldAdapter $adapter,
     HeraldTranscript $transcript) {
 
+    // TODO: Convert these to transactions. The way Maniphest deals with these
+    // transactions is currently unconventional and messy.
+
     $save_again = false;
     $cc_phids = $adapter->getCcPHIDs();
     if ($cc_phids) {
@@ -343,12 +348,6 @@ final class ManiphestTransactionEditor
       $save_again = true;
     }
 
-    $assign_phid = $adapter->getAssignPHID();
-    if ($assign_phid) {
-      $object->setOwnerPHID($assign_phid);
-      $save_again = true;
-    }
-
     $project_phids = $adapter->getProjectPHIDs();
     if ($project_phids) {
       $existing_projects = $object->getProjectPHIDs();
@@ -361,6 +360,17 @@ final class ManiphestTransactionEditor
     if ($save_again) {
       $object->save();
     }
+
+    $xactions = array();
+
+    $assign_phid = $adapter->getAssignPHID();
+    if ($assign_phid) {
+      $xactions[] = id(new ManiphestTransaction())
+        ->setTransactionType(ManiphestTransaction::TYPE_OWNER)
+        ->setNewValue($assign_phid);
+    }
+
+    return $xactions;
   }
 
   protected function requireCapabilities(

src/applications/metamta/contentsource/PhabricatorContentSource.php

@@ -10,6 +10,7 @@ final class PhabricatorContentSource {
   const SOURCE_TABLET   = 'tablet';
   const SOURCE_FAX      = 'fax';
   const SOURCE_CONSOLE  = 'console';
+  const SOURCE_HERALD   = 'herald';
   const SOURCE_LEGACY   = 'legacy';
 
   private $source;
@@ -70,7 +71,8 @@ final class PhabricatorContentSource {
       self::SOURCE_FAX      => pht('Fax'),
       self::SOURCE_CONSOLE  => pht('Console'),
       self::SOURCE_LEGACY   => pht('Legacy'),
-      self::SOURCE_UNKNOWN  => pht('Other'),
+      self::SOURCE_HERALD   => pht('Herald'),
+      self::SOURCE_UNKNOWN  => pht('Old World'),
     );
   }
 

src/applications/metamta/contentsource/PhabricatorContentSourceView.php

@@ -12,15 +12,7 @@ final class PhabricatorContentSourceView extends AphrontView {
   public function render() {
     require_celerity_resource('phabricator-content-source-view-css');
 
-    $map = array(
-      PhabricatorContentSource::SOURCE_WEB      => pht('Web'),
-      PhabricatorContentSource::SOURCE_CONDUIT  => pht('Conduit'),
-      PhabricatorContentSource::SOURCE_EMAIL    => pht('Email'),
-      PhabricatorContentSource::SOURCE_MOBILE   => pht('Mobile'),
-      PhabricatorContentSource::SOURCE_TABLET   => pht('Tablet'),
-      PhabricatorContentSource::SOURCE_FAX      => pht('Fax'),
-      PhabricatorContentSource::SOURCE_LEGACY   => pht('Old World'),
-    );
+    $map = PhabricatorContentSource::getSourceNameMap();
 
     $source = $this->contentSource->getSource();
     $type = idx($map, $source, null);

src/applications/pholio/editor/PholioMockEditor.php

@@ -412,7 +412,9 @@ final class PholioMockEditor extends PhabricatorApplicationTransactionEditor {
     return true;
   }
 
-  protected function supportsHerald() {
+  protected function shouldApplyHeraldRules(
+    PhabricatorLiskDAO $object,
+    array $xactions) {
     return true;
   }
 
@@ -429,6 +431,8 @@ final class PholioMockEditor extends PhabricatorApplicationTransactionEditor {
     HeraldAdapter $adapter,
     HeraldTranscript $transcript) {
 
+    // TODO: Convert this to be transaction-based.
+
     $cc_phids = $adapter->getCcPHIDs();
     if ($cc_phids) {
       id(new PhabricatorSubscriptionsEditor())
@@ -437,6 +441,8 @@ final class PholioMockEditor extends PhabricatorApplicationTransactionEditor {
         ->subscribeImplicit($cc_phids)
         ->save();
     }
+
+    return array();
   }
 
   protected function sortTransactions(array $xactions) {

src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php

@@ -23,6 +23,20 @@ abstract class PhabricatorApplicationTransactionEditor
   private $subscribers;
 
   private $isPreview;
+  private $isHeraldEditor;
+  private $actingAsPHID;
+
+  public function setActingAsPHID($acting_as_phid) {
+    $this->actingAsPHID = $acting_as_phid;
+    return $this;
+  }
+
+  public function getActingAsPHID() {
+    if ($this->actingAsPHID) {
+      return $this->actingAsPHID;
+    }
+    return $this->getActor()->getPHID();
+  }
 
   /**
    * When the editor tries to apply transactions that have no effect, should
@@ -105,6 +119,15 @@ abstract class PhabricatorApplicationTransactionEditor
     return $this->isPreview;
   }
 
+  public function setIsHeraldEditor($is_herald_editor) {
+    $this->isHeraldEditor = $is_herald_editor;
+    return $this;
+  }
+
+  public function getIsHeraldEditor() {
+    return $this->isHeraldEditor;
+  }
+
   public function getTransactionTypes() {
     $types = array();
 
@@ -391,9 +414,14 @@ abstract class PhabricatorApplicationTransactionEditor
 
     // TODO: This needs to be more sophisticated once we have meta-policies.
     $xaction->setViewPolicy(PhabricatorPolicies::POLICY_PUBLIC);
-    $xaction->setEditPolicy($actor->getPHID());
 
-    $xaction->setAuthorPHID($actor->getPHID());
+    if ($actor->isOmnipotent()) {
+      $xaction->setEditPolicy(PhabricatorPolicies::POLICY_NOONE);
+    } else {
+      $xaction->setEditPolicy($actor->getPHID());
+    }
+
+    $xaction->setAuthorPHID($this->getActingAsPHID());
     $xaction->setContentSource($this->getContentSource());
     $xaction->attachViewer($actor);
     $xaction->attachObject($object);
@@ -575,10 +603,6 @@ abstract class PhabricatorApplicationTransactionEditor
         $this->applyExternalEffects($object, $xaction);
       }
 
-      if ($this->supportsHerald()) {
-        $this->applyHeraldRules($object, $xactions);
-      }
-
       $xactions = $this->applyFinalEffects($object, $xactions);
 
       if ($read_locking) {
@@ -588,6 +612,63 @@ abstract class PhabricatorApplicationTransactionEditor
 
     $object->saveTransaction();
 
+    // Now that we've completely applied the core transaction set, try to apply
+    // Herald rules. Herald rules are allowed to either take direct actions on
+    // the database (like writing flags), or take indirect actions (like saving
+    // some targets for CC when we generate mail a little later), or return
+    // transactions which we'll apply normally using another Editor.
+
+    // First, check if *this* is a sub-editor which is itself applying Herald
+    // rules: if it is, stop working and return so we don't descend into
+    // madness.
+
+    // Otherwise, we're not a Herald editor, so process Herald rules (possibly
+    // using a Herald editor to apply resulting transactions) and then send out
+    // mail, notifications, and feed updates about everything.
+
+    if ($this->getIsHeraldEditor()) {
+      // We are the Herald editor, so stop work here and return the updated
+      // transactions.
+      return $xactions;
+    } else if ($this->shouldApplyHeraldRules($object, $xactions)) {
+      // We are not the Herald editor, so try to apply Herald rules.
+      $herald_xactions = $this->applyHeraldRules($object, $xactions);
+
+      if ($herald_xactions) {
+        // NOTE: We're acting as the omnipotent user because rules deal with
+        // their own policy issues. We use a synthetic author PHID (the
+        // Herald application) as the author of record, so that transactions
+        // will render in a reasonable way ("Herald assigned this task ...").
+        $herald_actor = PhabricatorUser::getOmnipotentUser();
+        $herald_phid = id(new PhabricatorApplicationHerald())->getPHID();
+
+        // TODO: It would be nice to give transactions a more specific source
+        // which points at the rule which generated them. You can figure this
+        // out from transcripts, but it would be cleaner if you didn't have to.
+
+        $herald_source = PhabricatorContentSource::newForSource(
+          PhabricatorContentSource::SOURCE_HERALD,
+          array());
+
+        $herald_editor = newv(get_class($this), array())
+          ->setContinueOnNoEffect(true)
+          ->setContinueOnMissingFields(true)
+          ->setParentMessageID($this->getParentMessageID())
+          ->setIsHeraldEditor(true)
+          ->setActor($herald_actor)
+          ->setActingAsPHID($herald_phid)
+          ->setContentSource($herald_source);
+
+        $herald_xactions = $herald_editor->applyTransactions(
+          $object,
+          $herald_xactions);
+
+        // Merge the new transactions into the transaction list: we want to
+        // send email and publish feed stories about them, too.
+        $xactions = array_merge($xactions, $herald_xactions);
+      }
+    }
+
     $this->loadHandles($xactions);
 
     $mail = null;
@@ -1792,7 +1873,9 @@ abstract class PhabricatorApplicationTransactionEditor
 /* -(  Herald Integration )-------------------------------------------------- */
 
 
-  protected function supportsHerald() {
+  protected function shouldApplyHeraldRules(
+    PhabricatorLiskDAO $object,
+    array $xactions) {
     return false;
   }
 
@@ -1832,14 +1915,14 @@ abstract class PhabricatorApplicationTransactionEditor
     $this->setHeraldAdapter($adapter);
     $this->setHeraldTranscript($xscript);
 
-    $this->didApplyHeraldRules($object, $adapter, $xscript);
+    return $this->didApplyHeraldRules($object, $adapter, $xscript);
   }
 
   protected function didApplyHeraldRules(
     PhabricatorLiskDAO $object,
     HeraldAdapter $adapter,
     HeraldTranscript $transcript) {
-
+    return array();
   }