[Fatal] Author override can cause infinite loop on post list screen

[peterwilsoncc]

Describe the bug

The post list can go in an infinite loop if the author replacement option is set.

A git bisect suggests it's following the merge of #1035 but it's possibly an interaction with a subsequently merged PR as the failure is intermittent.

Steps to Reproduce

1. Create multiple sites running Distributor on develop branch
2. Connect them
3. Create a few posts on the first site
4. Pull a few posts to the second site
5. Visit the posts listing in the dashboard
6. An infinite loop occurs.

Screenshots, screen recording, code snippet

Environment information

No response

WordPress information

Site info

### wp-core ###

version: 6.2.3-alpha-55842
site_language: en_US
user_language: en_US
timezone: +00:00
permalink: /%year%/%monthnum%/%postname%/
https_status: false
multisite: false
user_registration: 0
blog_public: 1
default_comment_status: open
environment_type: local
user_count: 5
dotorg_communication: true

### wp-paths-sizes ###

wordpress_path: /vagrant/wp-build
wordpress_size: loading...
uploads_path: /vagrant/content/uploads
uploads_size: loading...
themes_path: /vagrant/content/themes
themes_size: loading...
plugins_path: /vagrant/content/plugins
plugins_size: loading...
database_size: loading...
total_size: loading...

### wp-dropins (1) ###

db.php: true

### wp-active-theme ###

name: Twenty Twenty-Three (twentytwentythree)
version: 1.1
author: the WordPress team
author_website: https://wordpress.org
parent_theme: none
theme_features: core-block-patterns, post-thumbnails, responsive-embeds, editor-styles, html5, automatic-feed-links, block-templates, widgets-block-editor
theme_path: /vagrant/wp-build/wp-content/themes/twentytwentythree

### wp-themes-inactive (12) ###

Twenty Eleven: version: 4.3, author: the WordPress team
Twenty Fifteen: version: 3.4, author: the WordPress team
Twenty Fourteen: version: 3.6, author: the WordPress team
Twenty Nineteen: version: 2.5, author: the WordPress team
Twenty Seventeen: version: 3.2, author: the WordPress team
Twenty Sixteen: version: 2.9, author: the WordPress team
Twenty Ten: version: 3.8, author: the WordPress team
Twenty Thirteen: version: 3.8, author: the WordPress team
Twenty Twelve: version: 3.9, author: the WordPress team
Twenty Twenty: version: 2.2, author: the WordPress team
Twenty Twenty-One: version: 1.8, author: the WordPress team
Twenty Twenty-Two: version: 1.4, author: the WordPress team

### wp-mu-plugins (6) ###

nope-post-abstraction-dumps.php: author: (undefined), version: (undefined)
nope-push-nope-pull.php: author: (undefined), version: (undefined)
query-monitor-file-mappings.php: author: (undefined), version: (undefined)
show-stable-dist.php: author: (undefined), version: (undefined)
snippet-auto-unlink.php: author: (undefined), version: (undefined)
unsafe-app-passwords.php: author: (undefined), version: (undefined)

### wp-plugins-active (3) ###

Distributor: version: 1.9.1, author: 10up Inc.
Query Monitor: version: 3.12.3, author: John Blackbourn
User Switching: version: 1.7.0, author: John Blackbourn & contributors

### wp-plugins-inactive (6) ###

Classic Editor: version: 1.6.3, author: WordPress Contributors
Distributor: version: 1.9.1, author: 10up Inc.
Distributor - Edit Remote Post Meta: version: 0.2.1, author: 10up
Newspack Image Credits: version: 1.0.1, author: Automattic, INN Labs, Project Argo
Test block: author: (undefined), version: (undefined)
Yoast SEO: version: 20.7, author: Team Yoast (latest version: 20.8)

### wp-media ###

image_editor: WP_Image_Editor_GD
imagick_module_version: Not available
imagemagick_version: Not available
imagick_version: Not available
file_uploads: File uploads is turned off
post_max_size: 1024M
upload_max_filesize: 1024M
max_effective_size: 1 GB
max_file_uploads: 20
gd_version: 2.3.3
gd_formats: GIF, JPEG, PNG, WebP, BMP, XPM
ghostscript_version: not available

### wp-server ###

server_architecture: Linux 5.15.0-30-generic x86_64
httpd_software: nginx/1.18.0
php_version: 7.4.33 64bit
php_sapi: fpm-fcgi
max_input_variables: 1000
time_limit: 900
memory_limit: 128M
admin_memory_limit: 256M
max_input_time: 900
upload_max_filesize: 1024M
php_post_max_size: 1024M
curl_version: 7.81.0 OpenSSL/3.0.2
suhosin: false
imagick_availability: false
pretty_permalinks: true

### wp-database ###

extension: mysqli
server_version: 8.0.30-0ubuntu0.22.04.1
client_version: mysqlnd 7.4.33
max_allowed_packet: 16777216
max_connections: 151

### wp-constants ###

WP_HOME: http://xu-distributor.local
WP_SITEURL: http://xu-distributor.local/wp
WP_CONTENT_DIR: /vagrant/content
WP_PLUGIN_DIR: /vagrant/content/plugins
WP_MEMORY_LIMIT: 40M
WP_MAX_MEMORY_LIMIT: 256M
WP_DEBUG: true
WP_DEBUG_DISPLAY: false
WP_DEBUG_LOG: true
SCRIPT_DEBUG: true
WP_CACHE: false
CONCATENATE_SCRIPTS: undefined
COMPRESS_SCRIPTS: undefined
COMPRESS_CSS: undefined
WP_ENVIRONMENT_TYPE: local
DB_CHARSET: utf8
DB_COLLATE: undefined

### wp-filesystem ###

wordpress: writable
wp-content: writable
uploads: writable
plugins: writable
themes: writable
mu-plugins: writable

### distributor ###

0: 1.9.1
1: No
2: N/A
3: 
	Override Author Byline: Yes
	Media Handling: Featured image only
4: N/A
5: 
	XU Single 2: 
- URL: http://vagrant.local/wp-json/
- Version: 1.9.1
- Status: valid
- Auth method: Username / Password
- Username: admin
- Roles Allowed to Push: administrator, editor
- Additional data: {"errors":[], "can_post":["post", "page", "attachment", "nav_menu_item", "wp_block", "wp_template", "wp_template_part", "wp_navigation"], "can_get":["post", "page", "attachment", "nav_menu_item", "wp_block", "wp_template", "wp_template_part", "wp_navigation"], "endpoint_suggestion":false, "is_authenticated":"yes"}

Code of Conduct

• I agree to follow this project's Code of Conduct

[peterwilsoncc]

This is an edge case caused by a post without an author specified or an author with the display name set to ''.

The DistributorPost::get_author_name() method is used by the author replacement hook and doesn't allow for the use case of an empty author display name. When running on the replacment hook, it triggers an infinite loop.

distributor/includes/classes/DistributorPost.php

Lines 496 to 515 in 3e44218

	protected function get_author_name( $author_name = '' ) {
	$settings = Utils\get_settings();
	if (
	empty( $settings['override_author_byline'] )
	|| $this->is_source
	|| $this->original_deleted
	|| ! $this->is_linked
	|| ! $this->connection_id
	|| ! $this->original_post_url
	) {
	if ( empty( $author_name ) ) {
	return get_the_author_meta( 'display_name', $this->post->post_author );
	}
	return $author_name;
	}
	$this->populate_source_site();
	return $this->source_site['name'];
	}

We're not seeing it in the E2E tests as the author display name is specified, I'm seeing it locally because I'm generating posts with wp post generate which produces posts without an author specified.

An empty display name is an edge case but probably something we should account for.