From 8b426c7e5c223d6034c3d2ebd06917b781e4b9aa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bartosz=20Dziewo=C5=84ski?= <matma.rex@gmail.com>
Date: Tue, 11 Jan 2022 22:58:57 +0100
Subject: [PATCH] Fix placeholder headings causing exceptions in
 getTranscludedFrom()

Follow-up to 8de940b58784391669b92663db7cd2c8da50e88b.

Change-Id: Iddf045105fac6ab8cdaa933fd2abcf6dbbd37d42
---
 includes/CommentUtils.php |  6 ++++--
 includes/HeadingItem.php  | 11 +++++++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/includes/CommentUtils.php b/includes/CommentUtils.php
index 0bb3a39da..b7bce0fad 100644
--- a/includes/CommentUtils.php
+++ b/includes/CommentUtils.php
@@ -518,10 +518,11 @@ class CommentUtils {
 	}
 
 	/**
-	 * @param ImmutableRange $range
+	 * @param ImmutableRange $range (must not be collapsed)
 	 * @return Node
 	 */
 	public static function getRangeFirstNode( ImmutableRange $range ): Node {
+		Assert::precondition( !$range->collapsed, 'Range is not collapsed' );
 		// PHP bug: childNodes can be null
 		return $range->startContainer->childNodes && $range->startContainer->childNodes->length ?
 			$range->startContainer->childNodes[ $range->startOffset ] :
@@ -529,10 +530,11 @@ class CommentUtils {
 	}
 
 	/**
-	 * @param ImmutableRange $range
+	 * @param ImmutableRange $range (must not be collapsed)
 	 * @return Node
 	 */
 	public static function getRangeLastNode( ImmutableRange $range ): Node {
+		Assert::precondition( !$range->collapsed, 'Range is not collapsed' );
 		// PHP bug: childNodes can be null
 		return $range->endContainer->childNodes && $range->endContainer->childNodes->length ?
 			$range->endContainer->childNodes[ $range->endOffset - 1 ] :
diff --git a/includes/HeadingItem.php b/includes/HeadingItem.php
index 1da1a6df5..b97a4c17c 100644
--- a/includes/HeadingItem.php
+++ b/includes/HeadingItem.php
@@ -97,4 +97,15 @@ class HeadingItem extends ThreadItem {
 			$this->getName() !== 'h-'
 		);
 	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function getTranscludedFrom() {
+		// Placeholder headings break the usual logic, because their ranges are collapsed
+		if ( $this->isPlaceholderHeading() ) {
+			return false;
+		}
+		return parent::getTranscludedFrom();
+	}
 }