MAGETWO-88018: [Forwardport] Display a more meaningful error message in case of misspelt module name #13731

 - Merge Pull Request #13731 from nmalevanec/magento2:2.3-develop-PR-port-12843
 - Merged commits:
   1. 34a1dee
   2. 82f701a
   3. 7a0ce57
   4. 57a6e17
   5. 70b2722
   6. d77d9a0

Author: magento-engcom-team

lib/internal/Magento/Framework/Module/Dir.php

@@ -45,6 +45,12 @@ public function getDir($moduleName, $type = '')
     {
         $path = $this->componentRegistrar->getPath(ComponentRegistrar::MODULE, $moduleName);
 
+        // An empty $type means it's getting the directory of the module itself.
+        if (empty($type) && !isset($path)) {
+            // Note: do not throw \LogicException, as it would break backwards-compatibility.
+            throw new \InvalidArgumentException("Module '$moduleName' is not correctly registered.");
+        }
+
         if ($type) {
             if (!in_array($type, [
                 self::MODULE_ETC_DIR,

lib/internal/Magento/Framework/Module/Test/Unit/DirTest.php

@@ -59,4 +59,17 @@ public function testGetDirModuleSubDirUnknown()
 
         $this->_model->getDir('Test_Module', 'unknown');
     }
+
+    /**
+     * @expectedException \InvalidArgumentException
+     * @expectedExceptionMessage Module 'Test Module' is not correctly registered.
+     */
+    public function testGetDirModuleIncorrectlyRegistered()
+    {
+        $this->moduleRegistryMock->expects($this->once())
+            ->method('getPath')
+            ->with($this->identicalTo(ComponentRegistrar::MODULE), $this->identicalTo('Test Module'))
+            ->willReturn(null);
+        $this->_model->getDir('Test Module');
+    }
 }