system/HTTP/RedirectResponse.php
public function withInput()
	{
		$session = $this->ensureSession();

		$input = [
			'get'  => $_GET ?? [],
			'post' => $_POST ?? [],
		];

		$session->setFlashdata('_ci_old_input', $input);

		// If the validator has any errors, transmit those back
		// so they can be displayed when the validation is
		// handled within a method different than displaying the form.
		$validator = Services::validation();
		if (! empty($validator->getErrors()))
		{
			$session->setFlashdata('_ci_validation_errors', serialize($validator->getErrors()));
		}

		return $this;
	}
public function withInput()
	{
		$session = $this->ensureSession();

		$input = [
			'get'  => $_GET ?? [],
			'post' => $_POST ?? [],
		];

		$session->setFlashdata('_ci_old_input', $input);

		// If the validator has any errors, transmit those back
		// so they can be displayed when the validation is
		// handled within a method different than displaying the form.
		$validator = Services::validation();
		if (! empty($validator->getErrors()))
		{
			$session->setFlashdata('_ci_validation_errors', serialize($validator->getErrors()));
		}

		return $this;
	}
Specifies that the current $_GET and $_POST arrays should be
packaged up with the response. It will then be available via
the 'old()' helper function.

@return $this