Corona: Throw if JSONView encoding fails

src/Lunr/Corona/JsonView.php

@@ -13,6 +13,7 @@
 use Lunr\Core\Configuration;
 use stdClass;
 use Throwable;
+use Lunr\Corona\Exceptions\InternalServerErrorException;
 
 /**
  * View class for displaying JSON return values.
@@ -81,14 +82,22 @@ public function print_page()
         header('Content-type: application/json');
         http_response_code($code);
 
+        $return = NULL;
         if ($this->request->sapi == 'cli')
         {
-            echo json_encode($json, JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT) . "\n";
+            $return = json_encode($json, JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT) . "\n";
         }
         else
         {
-            echo json_encode($json, JSON_UNESCAPED_UNICODE);
+            $return = json_encode($json, JSON_UNESCAPED_UNICODE);
         }
+
+        if (json_last_error() !== JSON_ERROR_NONE)
+        {
+            throw new InternalServerErrorException('JSON encoding failed: ' . json_last_error_msg());
+        }
+
+        echo $return;
     }
 
     /**

src/Lunr/Corona/Tests/JsonViewPrintTest.php

@@ -135,6 +135,58 @@ public function testPrintPagePrintsJsonWithoutMessage(): void
         $this->unmock_function('http_response_code');
     }
 
+    /**
+     * Test that print_page() prints JSON with an empty string as message if message is missing.
+     *
+     * @runInSeparateProcess
+     * @requires PHP 5.5.12
+     * @covers   \Lunr\Corona\JsonView::print_page
+     */
+    public function testPrintPageThrowsOnEncodingFailure()
+    {
+        $this->response->expects($this->once())
+                       ->method('get_return_code_identifiers')
+                       ->with($this->equalTo(TRUE))
+                       ->will($this->returnValue('id'));
+
+        $this->response->expects($this->once())
+                       ->method('get_error_info')
+                       ->with($this->equalTo('id'))
+                       ->will($this->returnValue(NULL));
+
+        $this->response->expects($this->once())
+                       ->method('get_error_message')
+                       ->with($this->equalTo('id'))
+                       ->will($this->returnValue(NULL));
+
+        $this->response->expects($this->once())
+                       ->method('get_return_code')
+                       ->with($this->equalTo('id'))
+                       ->will($this->returnValue(404));
+
+        $this->response->expects($this->once())
+                       ->method('get_response_data')
+                       ->will($this->returnValue($this->json));
+
+        $this->request->expects($this->once())
+                      ->method('__get')
+                      ->with($this->equalTo('sapi'))
+                      ->will($this->returnValue('cli'));
+
+        $this->expectException('Lunr\Corona\Exceptions\InternalServerErrorException');
+        $this->expectExceptionMessage('JSON encoding failed: some error occurred');
+
+        $this->mock_function('header', function() {});
+        $this->mock_function('json_last_error', function() { return 1; });
+        $this->mock_function('json_last_error_msg', function() { return 'some error occurred'; });
+
+        $this->class->print_page();
+
+        $this->unmock_function('json_last_error_msg');
+        $this->unmock_function('json_last_error');
+        $this->unmock_function('header');
+    }
+
     /**
      * Test that print_page() prints JSON.
      *