From 22618cef9affc032537930d3f1144759e5d90893 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@git.wordpress.org>
Date: Tue, 16 Feb 2021 17:32:58 +0000
Subject: [PATCH] Feeds: Fix the URL returned by `get_feed_link()` when pretty
 permalinks are not in use.

Props hauvong, peterwilsoncc, SergeyBiryukov

Fixes #51839


git-svn-id: https://develop.svn.wordpress.org/trunk@50354 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/link-template.php        |  2 +-
 tests/phpunit/tests/link/getFeedLink.php | 67 ++++++++++++++++++++++++
 2 files changed, 68 insertions(+), 1 deletion(-)
 create mode 100644 tests/phpunit/tests/link/getFeedLink.php

diff --git a/src/wp-includes/link-template.php b/src/wp-includes/link-template.php
index 85b61e3a5a..9554de3d2f 100644
--- a/src/wp-includes/link-template.php
+++ b/src/wp-includes/link-template.php
@@ -690,7 +690,7 @@ function get_feed_link( $feed = '' ) {
 
 	$permalink = $wp_rewrite->get_feed_permastruct();
 
-	if ( '' !== $permalink ) {
+	if ( $permalink ) {
 		if ( false !== strpos( $feed, 'comments_' ) ) {
 			$feed      = str_replace( 'comments_', '', $feed );
 			$permalink = $wp_rewrite->get_comment_feed_permastruct();
diff --git a/tests/phpunit/tests/link/getFeedLink.php b/tests/phpunit/tests/link/getFeedLink.php
new file mode 100644
index 0000000000..41d6d922d2
--- /dev/null
+++ b/tests/phpunit/tests/link/getFeedLink.php
@@ -0,0 +1,67 @@
+<?php
+
+/**
+ * @group link
+ * @covers ::get_feed_link
+ */
+class Tests_Link_GetFeedLink extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 51839
+	 * @dataProvider data_plain_permastruct
+	 *
+	 * @param string $expected Expected suffix to home_url().
+	 * @param string $type     Feed type to request.
+	 */
+	public function tests_plain_permastruct( $expected, $type ) {
+		$this->set_permalink_structure( '' );
+
+		$this->assertSame( home_url( $expected ), get_feed_link( $type ) );
+	}
+
+	public function data_plain_permastruct() {
+		return array(
+			array( '?feed=rss2', '' ),
+			array( '?feed=atom', 'atom' ),
+			array( '?feed=get-feed-link', 'get-feed-link' ),
+			array( '?feed=comments-rss2', 'comments_rss2' ),
+			array( '?feed=comments-atom', 'comments_atom' ),
+		);
+	}
+
+	/**
+	 * @ticket 51839
+	 * @dataProvider data_pretty_permastruct
+	 *
+	 * @param string $expected Expected suffix to home_url().
+	 * @param string $type     Feed type to request.
+	 */
+	public function tests_pretty_permastruct( $expected, $type ) {
+		$this->set_permalink_structure( '/%year%/%monthnum%/%day%/%postname%/' );
+
+		$this->assertSame( home_url( $expected ), get_feed_link( $type ) );
+	}
+
+	/**
+	 * @ticket 51839
+	 * @dataProvider data_pretty_permastruct
+	 *
+	 * @param string $expected Expected suffix to home_url().
+	 * @param string $type     Feed type to request.
+	 */
+	public function tests_pretty_permastruct_with_prefix( $expected, $type ) {
+		$this->set_permalink_structure( '/archives/%post_id%/%postname%/' );
+
+		$this->assertSame( home_url( $expected ), get_feed_link( $type ) );
+	}
+
+	public function data_pretty_permastruct() {
+		return array(
+			array( '/feed/', '' ),
+			array( '/feed/atom/', 'atom' ),
+			array( '/feed/get-feed-link/', 'get-feed-link' ),
+			array( '/comments/feed/', 'comments_rss2' ),
+			array( '/comments/feed/atom/', 'comments_atom' ),
+		);
+	}
+}