Compatibility Issue with WooCommerce Variable Products and MultilingualPress

We are getting an issue when creating a Variable Product with WooCommerce and then attempting to translate that error via MultilingualPress.

Steps to recreate:

On a multisite install with at least two sites
Ensure WooCommerce is installed and network active
Ensure MultilingualPress is installed and network active
- Ensure MultilingualPress has been configured to work with WooCommerce in the settings screen, and the Product post type is translatable
Create a new Woo product, give it a test title and some content
In the Product data meta box, set the project type to Variable product
In the attributes tab Add an attribute, something like Attribute 1 with the values 1 | 2, be sure to save the attributes when you have finished
In the Variations tab generate the variations from the attributes
Publish the product
Scroll down to the Translation for... that relates to the other site on your network
Click the Create a new Product, and use it as translation in... radio button
Click the post publish button to trigger the translation
The following error will occur:

Fatal error: Uncaught Error: Return value of AssetManagerFramework\replace_attached_file() must be of the type string, bool returned
in /usr/src/app/vendor/humanmade/asset-manager-framework/inc/namespace.php on line 217

Call stack:

AssetManagerFramework\replace_attached_file()
wp-includes/class-wp-hook.php:307
WP_Hook::apply_filters()
wp-includes/plugin.php:189
apply_filters()
wp-includes/post.php:744
get_attached_file()
content/plugins/multilingualpress/src/modules/WooCommerce/TranslationUi/Product/MetaboxAction.php:1064
Inpsyde\M\M\W\T\P\MetaboxAction::getSourceProductVariationAttachmentData()
content/plugins/multilingualpress/src/modules/WooCommerce/TranslationUi/Product/MetaboxAction.php:172
Inpsyde\M\M\W\T\P\MetaboxAction::doSaveOperation()
content/plugins/multilingualpress/src/modules/WooCommerce/TranslationUi/Product/MetaboxAction.php:131
Inpsyde\M\M\W\T\P\MetaboxAction::save()
content/plugins/multilingualpress/src/modules/WooCommerce/ProductMetaboxesBehaviorActivator.php:140
Inpsyde\M\M\W\ProductMetaboxesBehaviorActivator::saveMetaboxes()
wp-includes/class-wp-hook.php:309
WP_Hook::apply_filters()
wp-includes/class-wp-hook.php:331
WP_Hook::do_action()
wp-includes/plugin.php:474
do_action()
content/plugins/multilingualpress/src/multilingualpress/TranslationUi/Post/MetaboxAction.php:470
Inpsyde\M\T\P\MetaboxAction::savePost()
content/plugins/multilingualpress/src/multilingualpress/TranslationUi/Post/MetaboxAction.php:279
Inpsyde\M\T\P\MetaboxAction::doSaveOperation()
content/plugins/multilingualpress/src/multilingualpress/TranslationUi/Post/MetaboxAction.php:114
Inpsyde\M\T\P\MetaboxAction::save()
content/plugins/multilingualpress/src/framework/Admin/Metabox/MetaboxUpdater.php:127
Inpsyde\M\F\A\M\MetaboxUpdater::saveMetabox()
content/plugins/multilingualpress/src/framework/Admin/Metabox/Metaboxes.php:455
Inpsyde\M\F\A\M\Metaboxes::saveMetaBoxes()
content/plugins/multilingualpress/src/framework/Admin/Metabox/Metaboxes.php:420
Inpsyde\M\F\A\M\Metaboxes::onPostSave()
content/plugins/multilingualpress/src/framework/Admin/Metabox/Metaboxes.php:245
Inpsyde\M\F\A\M\Metaboxes::Inpsyde\M\F\A\M\{closure}()
wp-includes/class-wp-hook.php:309
WP_Hook::apply_filters()
wp-includes/class-wp-hook.php:331
WP_Hook::do_action()
wp-includes/plugin.php:474
do_action()
wp-includes/post.php:4698
wp_insert_post()
wp-includes/post.php:4789
wp_update_post()
wp-admin/includes/post.php:426
edit_post()
wp-admin/post.php:227

Mitigation

If you override the default image that is added to each product variation, and attempt to translate the product again, the above error does not occur.

humanmade / asset-manager-framework

Compatibility Issue with WooCommerce Variable Products and MultilingualPress #54