PHPLIB-570: Consult NamespaceNotFound error code in DropCollection

Also changes the try/catch to CommandException and allows the original command reply to be returned instead of a synthetic document (based on pre-3.2 server responses).

Author: jmikola

src/Operation/DropCollection.php

@@ -18,7 +18,7 @@
 namespace MongoDB\Operation;
 
 use MongoDB\Driver\Command;
-use MongoDB\Driver\Exception\RuntimeException as DriverRuntimeException;
+use MongoDB\Driver\Exception\CommandException;
 use MongoDB\Driver\Server;
 use MongoDB\Driver\Session;
 use MongoDB\Driver\WriteConcern;
@@ -38,6 +38,9 @@
  */
 class DropCollection implements Executable
 {
+    /** @var integer */
+    private static $errorCodeNamespaceNotFound = 26;
+
     /** @var string */
     private static $errorMessageNamespaceNotFound = 'ns not found';
 
@@ -122,13 +125,13 @@ public function execute(Server $server)
 
         try {
             $cursor = $server->executeWriteCommand($this->databaseName, $command, $this->createOptions());
-        } catch (DriverRuntimeException $e) {
+        } catch (CommandException $e) {
             /* The server may return an error if the collection does not exist.
-             * Check for an error message (unfortunately, there isn't a code)
-             * and NOP instead of throwing.
-             */
-            if ($e->getMessage() === self::$errorMessageNamespaceNotFound) {
-                return (object) ['ok' => 0, 'errmsg' => self::$errorMessageNamespaceNotFound];
+             * Check for an error code (or message for pre-3.2 servers) and
+             * return the command reply instead of throwing. */
+            if ($e->getCode() === self::$errorCodeNamespaceNotFound ||
+                $e->getMessage() === self::$errorMessageNamespaceNotFound) {
+                return $e->getResultDocument();
             }
 
             throw $e;

tests/Operation/DropCollectionFunctionalTest.php

@@ -38,8 +38,9 @@ public function testDropExistingCollection()
         $this->assertEquals(1, $writeResult->getInsertedCount());
 
         $operation = new DropCollection($this->getDatabaseName(), $this->getCollectionName());
-        $operation->execute($server);
+        $commandResult = $operation->execute($server);
 
+        $this->assertCommandSucceeded($commandResult);
         $this->assertCollectionDoesNotExist($this->getCollectionName());
     }
 
@@ -51,7 +52,11 @@ public function testDropNonexistentCollection()
         $this->assertCollectionDoesNotExist($this->getCollectionName());
 
         $operation = new DropCollection($this->getDatabaseName(), $this->getCollectionName());
-        $operation->execute($this->getPrimaryServer());
+        $commandResult = $operation->execute($this->getPrimaryServer());
+
+        $this->assertIsObject($commandResult);
+        $this->assertObjectHasAttribute('ok', $commandResult);
+        $this->assertEquals(0, $commandResult->ok);
     }
 
     public function testSessionOption()