Remove trivial implementations of getPagingColumn()

Summary:
Ref T7803. Some Query subclasses implement getPagingColumn() in a trivial way, usually to provide a table alias.

Formalize the concept of a primary table alias, and remove obsoleted getPagingColumn() implementations.

Test Plan: Issued affected queries.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T7803

Differential Revision: https://secure.phabricator.com/D12356

src/applications/files/query/PhabricatorFileQuery.php

@@ -331,8 +331,8 @@ final class PhabricatorFileQuery
     return $this->formatWhereClause($where);
   }
 
-  protected function getPagingColumn() {
-    return 'f.id';
+  protected function getPrimaryTableAlias() {
+    return 'f';
   }
 
   public function getQueryApplicationClass() {

src/applications/macro/query/PhabricatorMacroQuery.php

@@ -225,8 +225,8 @@ final class PhabricatorMacroQuery
     return $macros;
   }
 
-  protected function getPagingColumn() {
-    return 'm.id';
+  protected function getPrimaryTableAlias() {
+    return 'm';
   }
 
   public function getQueryApplicationClass() {

src/applications/maniphest/query/ManiphestTaskQuery.php

@@ -1137,8 +1137,8 @@ final class ManiphestTaskQuery extends PhabricatorCursorPagedPolicyAwareQuery {
       ));
   }
 
-  protected function getApplicationSearchObjectPHIDColumn() {
-    return 'task.phid';
+  protected function getPrimaryTableAlias() {
+    return 'task';
   }
 
   public function getQueryApplicationClass() {

src/applications/metamta/query/PhabricatorMetaMTAApplicationEmailQuery.php

@@ -114,12 +114,8 @@ final class PhabricatorMetaMTAApplicationEmailQuery
     return $this->formatWhereClause($where);
   }
 
-  protected function getPagingColumn() {
-    return 'appemail.id';
-  }
-
-  protected function getApplicationSearchObjectPHIDColumn() {
-    return 'appemail.phid';
+  protected function getPrimaryTableAlias() {
+    return 'appemail';
   }
 
   public function getQueryApplicationClass() {

src/applications/people/query/PhabricatorPeopleQuery.php

@@ -288,12 +288,8 @@ final class PhabricatorPeopleQuery
     return $this->formatWhereClause($where);
   }
 
-  protected function getPagingColumn() {
-    return 'user.id';
-  }
-
-  protected function getApplicationSearchObjectPHIDColumn() {
-    return 'user.phid';
+  protected function getPrimaryTableAlias() {
+    return 'user';
   }
 
   public function getQueryApplicationClass() {

src/applications/project/query/PhabricatorProjectQuery.php

@@ -380,8 +380,8 @@ final class PhabricatorProjectQuery
     return 'PhabricatorProjectApplication';
   }
 
-  protected function getApplicationSearchObjectPHIDColumn() {
-    return 'p.phid';
+  protected function getPrimaryTableAlias() {
+    return 'p';
   }
 
 }

src/applications/slowvote/query/PhabricatorSlowvoteQuery.php

@@ -174,8 +174,8 @@ final class PhabricatorSlowvoteQuery
     return implode(' ', $joins);
   }
 
-  protected function getPagingColumn() {
-    return 'p.id';
+  protected function getPrimaryTableAlias() {
+    return 'p';
   }
 
   public function getQueryApplicationClass() {

src/infrastructure/query/policy/PhabricatorCursorPagedPolicyAwareQuery.php

@@ -147,6 +147,21 @@ abstract class PhabricatorCursorPagedPolicyAwareQuery
   }
 
 
+  /**
+   * Return the alias this query uses to identify the primary table.
+   *
+   * Some automatic query constructions may need to be qualified with a table
+   * alias if the query performs joins which make column names ambiguous. If
+   * this is the case, return the alias for the primary table the query
+   * uses; generally the object table which has `id` and `phid` columns.
+   *
+   * @return string Alias for the primary table.
+   */
+  protected function getPrimaryTableAlias() {
+    return null;
+  }
+
+
 /* -(  Paging  )------------------------------------------------------------- */
 
 
@@ -450,7 +465,7 @@ abstract class PhabricatorCursorPagedPolicyAwareQuery
 
     return array(
       'id' => array(
-        'table' => null,
+        'table' => $this->getPrimaryTableAlias(),
         'column' => 'id',
         'reverse' => false,
         'type' => 'int',
@@ -657,15 +672,23 @@ abstract class PhabricatorCursorPagedPolicyAwareQuery
 
   /**
    * Get the name of the query's primary object PHID column, for constructing
-   * JOIN clauses. Normally (and by default) this is just `"phid"`, but if the
-   * query construction requires a table alias it may be something like
-   * `"task.phid"`.
+   * JOIN clauses. Normally (and by default) this is just `"phid"`, but it may
+   * be something more exotic.
+   *
+   * See @{method:getPrimaryTableAlias} if the column needs to be qualified with
+   * a table alias.
    *
    * @return string Column name.
    * @task appsearch
    */
   protected function getApplicationSearchObjectPHIDColumn() {
-    return 'phid';
+    if ($this->getPrimaryTableAlias()) {
+      $prefix = $this->getPrimaryTableAlias().'.';
+    } else {
+      $prefix = '';
+    }
+
+    return $prefix.'phid';
   }