Change edit links for templates and template parts

lib/full-site-editing/template-loader.php

@@ -266,3 +266,28 @@ function gutenberg_resolve_template_for_new_post( $wp_query ) {
 		$wp_query->set( 'post_status', 'auto-draft' );
 	}
 }
+
+/**
+ * Redirect the edit links for templates to the site editor.
+ *
+ * @param string $link    The original link.
+ * @param int    $post_id The custom post id.
+ */
+function gutenberg_get_edit_template_link( $link, $post_id ) {
+	$post = get_post( $post_id );
+
+	if ( ! in_array( $post->post_type, array( 'wp_template', 'wp_template_part' ), true ) ) {
+		return $link;
+	}
+
+	$template = _build_block_template_result_from_post( $post );
+
+	if ( is_wp_error( $template ) ) {
+		return $link;
+	}
+
+	$edit_link = 'themes.php?page=gutenberg-edit-site&postId=%1$s&postType=%2$s';
+
+	return admin_url( sprintf( $edit_link, urlencode( $template->id ), $template->type ) );
+}
+add_filter( 'get_edit_post_link', 'gutenberg_get_edit_template_link', 10, 2 );

phpunit/full-site-editing/template-loader-test.php

@@ -0,0 +1,44 @@
+<?php
+/**
+ * This class tests block template loader functions
+ *
+ * @package Gutenberg
+ */
+
+class WP_Template_Loader_Test extends WP_UnitTestCase {
+
+	public function test_gutenberg_get_edit_template_link_returns_admin_url_link_for_template_posts() {
+		$stylesheet = get_stylesheet();
+		$args       = array(
+			'post_type'    => 'wp_template',
+			'post_name'    => 'my_template',
+			'post_title'   => 'My Template',
+			'post_content' => 'Content',
+			'post_excerpt' => 'Description of my template.',
+			'tax_input'    => array(
+				'wp_theme' => array(
+					$stylesheet,
+				),
+			),
+		);
+		$post       = self::factory()->post->create_and_get( $args );
+
+		wp_set_post_terms( $post->ID, get_stylesheet(), 'wp_theme' );
+		$default_url = 'https://some.link';
+		$url         = gutenberg_get_edit_template_link( $default_url, $post->ID );
+		$this->assertIsString( $url );
+		$this->assertNotSame( $default_url, $url );
+		$this->assertStringContainsString( 'themes.php', $url );
+		$this->assertStringContainsString( 'postId', $url );
+		$this->assertStringContainsString( $stylesheet, $url );
+		wp_delete_post( $post->ID );
+	}
+
+	public function test_gutenberg_get_edit_template_link_returns_default_link_for_non_template_posts() {
+		$post        = self::factory()->post->create_and_get();
+		$default_url = 'https://some.link';
+		$url         = gutenberg_get_edit_template_link( $default_url, $post->ID );
+		$this->assertSame( $default_url, $url );
+		wp_delete_post( $post->ID );
+	}
+}