How can I programatically change the (D8 core) workflow state of an entity with Content Moderation?

Question

I'm using Drupal 8.4-rc2. When you enable the Workflow and Content Moderation modules, you automatically get the Editorial Workflow as a demonstration.

The states are as follows:

• Archived
• Draft
• Published

And the transitions are as follows:

• Create new draft (from draft/published to draft)
• Publish (from draft/published to published)

How can I programatically call a transition? Or, how can I programatically change the state without calling a transition (although this seems to violate the spirit of having transitions defined in the first place)?

Specifically, I have a node subject to content moderation (states: archived, draft, published). By default, on the edit node page, the node is saved in the original state (so a draft node is saved as a draft). I want to add a second button "save as published" with a submit handler, but I don't understand how I can programatically change the state.

What I do understand so far is that workflows are entities and so are states, so it's different than Drupal 7 in which most workflow-type modules used fields to track what was going on.

I checked the Examples module but there's nothing on configuration management/workflows yet.

Answer 1

A great example could be found in Content Moderation module's code.

$entity->set('moderation_state', $new_state);
if ($entity instanceof RevisionLogInterface) {
  $entity->setRevisionLogMessage($form_state->getValue('revision_log'));
  $entity->setRevisionUserId($this->currentUser()->id());
}
$entity->save();

Answer 2

I'm not heavily using D8 yet, but in D7's Workbench Moderation module nodes had a moderation_state field that was Draft or Published. Transitions in D7 were typically for User Role workflows whereas in code you typically modified the node states directly via node_load and node_save .... If D8 was inspired by the d7 module, the implementation may be similar.

Did you see the Tests referenced here found in the Examples links: https://www.drupal.org/docs/8/core/modules/workflows/overview and example node moderation field modifications here http://cgit.drupalcode.org/drupal/tree/core/modules/content_moderation/tests/src/Functional/ModerationStateNodeTest.php