Issue #3211866 by mondrake, daffie: Upsert::execute() return values are inconsistent

(cherry picked from commit 8e4a7d250dd2a8c24353b7d54bdb892efaa9cd67)

core/lib/Drupal/Core/Database/Driver/pgsql/Upsert.php

@@ -20,6 +20,7 @@ public function execute() {
     }
 
     $stmt = $this->connection->prepareStatement((string) $this, $this->queryOptions);
+    $stmt->allowRowCount = TRUE;
 
     // Fetch the list of blobs and sequences used on that table.
     $table_information = $this->connection->schema()->queryTableInformation($this->table);
@@ -82,13 +83,12 @@ public function execute() {
     try {
       $stmt->execute(NULL, $options);
       $this->connection->releaseSavepoint();
+      return $stmt->rowCount();
     }
     catch (\Exception $e) {
       $this->connection->rollbackSavepoint();
       throw $e;
     }
-
-    return TRUE;
   }
 
   /**

core/lib/Drupal/Core/Database/Query/Upsert.php

@@ -88,7 +88,12 @@ protected function preExecute() {
   }
 
   /**
-   * {@inheritdoc}
+   * Executes the UPSERT operation.
+   *
+   * @return int
+   *   An integer indicating the number of rows affected by the operation. Do
+   *   not rely on this value as a precise indication of the actual rows
+   *   affected: different database engines return different values.
    */
   public function execute() {
     if (!$this->preExecute()) {
@@ -103,12 +108,12 @@ public function execute() {
       }
     }
 
-    $last_insert_id = $this->connection->query((string) $this, $values, $this->queryOptions);
+    $affected_rows = $this->connection->query((string) $this, $values, $this->queryOptions);
 
     // Re-initialize the values array so that we can re-use this query.
     $this->insertValues = [];
 
-    return $last_insert_id;
+    return $affected_rows;
   }
 
 }

core/tests/Drupal/KernelTests/Core/Database/UpsertTest.php

@@ -37,7 +37,9 @@ public function testUpsert() {
       'name' => 'Meredith',
     ]);
 
-    $upsert->execute();
+    $result = $upsert->execute();
+    $this->assertIsInt($result);
+    $this->assertGreaterThanOrEqual(2, $result, 'The result of the upsert operation should report that at least two rows were affected.');
 
     $num_records_after = $connection->query('SELECT COUNT(*) FROM {test_people}')->fetchField();
     $this->assertEqual($num_records_before + 1, $num_records_after, 'Rows were inserted and updated properly.');
@@ -75,7 +77,9 @@ public function testUpsertWithKeywords() {
       'update' => 'Update value 1 updated',
     ]);
 
-    $upsert->execute();
+    $result = $upsert->execute();
+    $this->assertIsInt($result);
+    $this->assertGreaterThanOrEqual(2, $result, 'The result of the upsert operation should report that at least two rows were affected.');
 
     $num_records_after = $this->connection->query('SELECT COUNT(*) FROM {select}')->fetchField();
     $this->assertEquals($num_records_before + 1, $num_records_after, 'Rows were inserted and updated properly.');