From e3d7978bc6005265ee08059ffe986a60143a0c3e Mon Sep 17 00:00:00 2001
From: =?utf8?q?Gerg=C5=91=20Tisza?= <tgr.huwiki@gmail.com>
Date: Wed, 27 Apr 2016 12:28:55 +0200
Subject: [PATCH] Enforce calling HTMLForm::prepareForm before displayForm

Bug: T133163
Change-Id: Idd5d117cb0dd65c195019dcd321cd4bf9024b426
---
 includes/htmlform/HTMLForm.php                | 11 +++++++++-
 .../includes/htmlform/HTMLFormTest.php        | 21 +++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)
 create mode 100644 tests/phpunit/includes/htmlform/HTMLFormTest.php

diff --git a/includes/htmlform/HTMLForm.php b/includes/htmlform/HTMLForm.php
index 8f8caf2b1b..d671029a25 100644
--- a/includes/htmlform/HTMLForm.php
+++ b/includes/htmlform/HTMLForm.php
@@ -1474,13 +1474,22 @@ class HTMLForm extends ContextSource {
 	 * @param string $fieldsetIDPrefix ID prefix for the "<fieldset>" tag of
 	 *   each subsection, ignored if empty.
 	 * @param bool &$hasUserVisibleFields Whether the section had user-visible fields.
+	 * @throws LogicException When called on uninitialized field data, e.g. When
+	 *  HTMLForm::displayForm was called without calling HTMLForm::prepareForm
+	 *  first.
 	 *
 	 * @return string
 	 */
 	public function displaySection( $fields,
 		$sectionName = '',
 		$fieldsetIDPrefix = '',
-		&$hasUserVisibleFields = false ) {
+		&$hasUserVisibleFields = false
+	) {
+		if ( $this->mFieldData === null ) {
+			throw new LogicException( 'HTMLForm::displaySection() called on uninitialized field data. '
+				. 'You probably called displayForm() without calling prepareForm() first.' );
+		}
+
 		$displayFormat = $this->getDisplayFormat();
 
 		$html = [];
diff --git a/tests/phpunit/includes/htmlform/HTMLFormTest.php b/tests/phpunit/includes/htmlform/HTMLFormTest.php
new file mode 100644
index 0000000000..b7e0053c72
--- /dev/null
+++ b/tests/phpunit/includes/htmlform/HTMLFormTest.php
@@ -0,0 +1,21 @@
+<?php
+
+
+class HTMLFormTest extends MediaWikiTestCase {
+	public function testGetHTML_empty() {
+		$form = new HTMLForm( [] );
+		$form->setTitle( Title::newFromText( 'Foo' ) );
+		$form->prepareForm();
+		$html = $form->getHTML( false );
+		$this->assertRegExp( '/<form\b/', $html );
+	}
+
+	/**
+	 * @expectedException LogicException
+	 */
+	public function testGetHTML_noPrepare() {
+		$form = new HTMLForm( [] );
+		$form->setTitle( Title::newFromText( 'Foo' ) );
+		$form->getHTML( false );
+	}
+}
-- 
2.20.1