Fix issue 966 dot array in old() function

system/HTTP/IncomingRequest.php

@@ -466,7 +466,7 @@ public function getUserAgent()
 	/**
 	 * Attempts to get old Input data that has been flashed to the session
 	 * with redirect_with_input(). It first checks for the data in the old
-	 * POST data, then the old GET data.
+	 * POST data, then the old GET data and finally check for dot arrays
 	 *
 	 * @param string $key
 	 *
@@ -490,6 +490,28 @@ public function getOldInput(string $key)
 		{
 			return $_SESSION['_ci_old_input']['get'][$key];
 		}
+
+		helper('array');
+
+		// Check for an array value in POST.
+		if (isset($_SESSION['_ci_old_input']['post']))
+		{
+			$value = dot_array_search($key, $_SESSION['_ci_old_input']['post']);
+			if ( ! is_null($value))
+			{
+				return $value;
+			}
+		}
+
+		// Check for an array value in GET.
+		if (isset($_SESSION['_ci_old_input']['get']))
+		{
+			$value = dot_array_search($key, $_SESSION['_ci_old_input']['get']);
+			if ( ! is_null($value))
+			{
+				return $value;
+			}
+		}
 	}
 
 	/**

user_guide_src/source/general/common_functions.rst

@@ -100,6 +100,8 @@ Service Accessors
 
 		// In the view
 		<input type="email" name="email" value="<?= old('email') ?>">
+		// Or with arrays
+		<input type="email" name="user[email]" value="<?= old('user.email') ?>">
 
 .. note:: If you are using the :doc:`form helper </helpers/form_helper>`, this feature is built-in. You only
 		need to use this function when not using the form helper.