From 62327715a0d25eb2ab161cfd3ff72475209885f2 Mon Sep 17 00:00:00 2001
From: Adam Silverstein <adamsilverstein@git.wordpress.org>
Date: Fri, 21 May 2021 15:28:39 +0000
Subject: [PATCH] Revisions: add a new filter for revisions to keep by post
 type.

Add a new `wp_{$post_type}_revisions_to_keep` filter that makes it convenient to filter the number of revisions created for a specific post type.

Overrides both the value of WP_POST_REVISIONS and the `wp_revisions_to_keep` filter.

Props dlh.
Fixes #51550.



git-svn-id: https://develop.svn.wordpress.org/trunk@50949 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/revision.php           | 19 ++++++++-
 tests/phpunit/tests/post/revisions.php | 59 ++++++++++++++++++++++++++
 2 files changed, 77 insertions(+), 1 deletion(-)

diff --git a/src/wp-includes/revision.php b/src/wp-includes/revision.php
index a1aad16812..5a090aaf58 100644
--- a/src/wp-includes/revision.php
+++ b/src/wp-includes/revision.php
@@ -564,7 +564,24 @@ function wp_revisions_to_keep( $post ) {
 	 * @param int     $num  Number of revisions to store.
 	 * @param WP_Post $post Post object.
 	 */
-	return (int) apply_filters( 'wp_revisions_to_keep', $num, $post );
+	$num = apply_filters( 'wp_revisions_to_keep', $num, $post );
+
+	/**
+	 * Filters the number of revisions to save for the given post by its post type.
+	 *
+	 * Overrides both the value of WP_POST_REVISIONS and the {@see 'wp_revisions_to_keep'} filter.
+	 *
+	 * The dynamic portion of the hook name, `$post->post_type`, refers to
+	 * the post type slug.
+	 *
+	 * @since 5.8.0
+	 *
+	 * @param int     $num  Number of revisions to store.
+	 * @param WP_Post $post Post object.
+	 */
+	$num = apply_filters( "wp_{$post->post_type}_revisions_to_keep", $num, $post );
+
+	return (int) $num;
 }
 
 /**
diff --git a/tests/phpunit/tests/post/revisions.php b/tests/phpunit/tests/post/revisions.php
index 7883483e40..5f0131835f 100644
--- a/tests/phpunit/tests/post/revisions.php
+++ b/tests/phpunit/tests/post/revisions.php
@@ -576,4 +576,63 @@ class Tests_Post_Revisions extends WP_UnitTestCase {
 
 		$this->assertSame( $revision_ids, array_values( wp_list_pluck( $revisions, 'ID' ) ) );
 	}
+
+	/*
+	 * @ticket 51550
+	 */
+	public function test_wp_revisions_to_keep_filter() {
+		$post = self::factory()->post->create_and_get(
+			array(
+				'post_title'   => 'some-post',
+				'post_type'    => 'post',
+				'post_content' => 'some_content',
+			)
+		);
+
+		$default  = wp_revisions_to_keep( $post );
+		$expected = $default + 1;
+
+		add_filter(
+			'wp_revisions_to_keep',
+			function () use ( $expected ) {
+				return $expected;
+			}
+		);
+
+		$this->assertSame( $expected, wp_revisions_to_keep( $post ) );
+	}
+
+	/*
+	 * @ticket 51550
+	 */
+	public function test_wp_post_type_revisions_to_keep_filter() {
+		$post = self::factory()->post->create_and_get(
+			array(
+				'post_title'   => 'some-post',
+				'post_type'    => 'post',
+				'post_content' => 'some_content',
+			)
+		);
+
+		$default = wp_revisions_to_keep( $post );
+		$generic = $default + 1;
+
+		add_filter(
+			'wp_revisions_to_keep',
+			function () use ( $generic ) {
+				return $generic;
+			}
+		);
+		$this->assertSame( $generic, wp_revisions_to_keep( $post ) );
+
+		$expected = $generic + 1;
+
+		add_filter(
+			"wp_{$post->post_type}_revisions_to_keep",
+			function () use ( $expected ) {
+				return $expected;
+			}
+		);
+		$this->assertSame( $expected, wp_revisions_to_keep( $post ) );
+	}
 }