From ffb86c05524a8ba32d1e5b251a2ce4b9ad670472 Mon Sep 17 00:00:00 2001
From: Boone Gorges <boonebgorges@git.wordpress.org>
Date: Mon, 4 Dec 2017 21:02:10 +0000
Subject: [PATCH] `get_the_category_by_ID()` should be taxonomy-agnostic.

Prior to 4.9, this function was accidentally taxonomy-agnostic in most cases.
The fix in [40979] caused a regression in this function. For backward
compatibility, we make it explicit that the query is by ID only.

See #42771.

git-svn-id: https://develop.svn.wordpress.org/trunk@42367 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/category-template.php         |  2 +-
 .../tests/category/getTheCategoryById.php     | 53 +++++++++++++++++++
 2 files changed, 54 insertions(+), 1 deletion(-)
 create mode 100644 tests/phpunit/tests/category/getTheCategoryById.php

diff --git a/src/wp-includes/category-template.php b/src/wp-includes/category-template.php
index 27061e7266..f2ed10895c 100644
--- a/src/wp-includes/category-template.php
+++ b/src/wp-includes/category-template.php
@@ -107,7 +107,7 @@ function get_the_category( $id = false ) {
  */
 function get_the_category_by_ID( $cat_ID ) {
 	$cat_ID   = (int) $cat_ID;
-	$category = get_term( $cat_ID, 'category' );
+	$category = get_term( $cat_ID );
 
 	if ( is_wp_error( $category ) ) {
 		return $category;
diff --git a/tests/phpunit/tests/category/getTheCategoryById.php b/tests/phpunit/tests/category/getTheCategoryById.php
new file mode 100644
index 0000000000..3b1a4e4825
--- /dev/null
+++ b/tests/phpunit/tests/category/getTheCategoryById.php
@@ -0,0 +1,53 @@
+<?php
+
+/**
+ * @group taxonomy
+ * @covers ::get_the_category_by_ID
+ */
+class Tests_Category_GetTheCategoryById extends WP_UnitTestCase {
+	public function test_success() {
+		$c = self::factory()->category->create( array(
+			'name' => 'Foo',
+		) );
+
+		$found = get_the_category_by_ID( $c );
+
+		$this->assertSame( 'Foo', $found );
+	}
+
+	/**
+	 * @ticket 42771
+	 */
+	public function test_should_return_link_for_term_from_another_taxonomy_on_primed_cache() {
+		register_taxonomy( 'wptests_tax', 'post' );
+
+		$t = self::factory()->term->create( array(
+			'taxonomy' => 'wptests_tax',
+			'name'     => 'Foo',
+		) );
+
+		$term = get_term( $t );
+
+		$found = get_the_category_by_ID( $t );
+
+		$this->assertSame( 'Foo', $found );
+	}
+
+	/**
+	 * @ticket 42771
+	 */
+	public function test_should_return_link_for_term_from_another_taxonomy_on_empty_cache() {
+		register_taxonomy( 'wptests_tax', 'post' );
+
+		$t = self::factory()->term->create( array(
+			'taxonomy' => 'wptests_tax',
+			'name'     => 'Foo',
+		) );
+
+		clean_term_cache( $t );
+
+		$found = get_the_category_by_ID( $t );
+
+		$this->assertSame( 'Foo', $found );
+	}
+}