Recreate missing connect terms if post is published

If a post is published, but somehow does not have an associated
_connect term, and the post is updated, recreate the _connect term
and re-associate any lost associations.

Author: jeremyfelt

includes/sync.php

@@ -87,6 +87,27 @@ function sync_shadow_taxonomies( int $post_id, \WP_Post $post_after, bool $updat
 		return;
 	}
 
+	// If a post is already published and not undergoing a status change, but does not
+	// have an associated term, create one.
+	if ( 'publish' === $status_before && 'publish' === $status_after && false === $term_after ) {
+		// In the very unlikely condition that a term _was_ associated, but now is
+		// lost to the ether, attempt to restore previous post associations.
+		$existing_associations = (array) get_post_meta( $post_id, "{$taxonomy}_associated_posts", true );
+		$existing_associations = array_filter( $existing_associations );
+
+		$new_term = wp_insert_term( $title_after, $taxonomy );
+
+		if ( is_wp_error( $new_term ) ) {
+			return;
+		}
+
+		foreach ( $existing_associations as $association ) {
+			wp_set_object_terms( $association, $new_term['term_id'], $taxonomy );
+		}
+
+		return;
+	}
+
 	// If the post transitioned from published to not published, remove the associated term.
 	if ( 'publish' !== $status_after && $term_before ) {
 		$associated_posts = get_objects_in_term( $term_before->term_id, $taxonomy );

tests/test-term-sync.php

@@ -539,6 +539,44 @@ public function test_post_trash_to_publish_creates_term_and_restores_relationshi
 		$this->assertEquals( array( $term->slug ), $associated_terms, 'Existing shadow term relationships should be restored when its connected post is moved from trash to publish.' );
 	}
 
+	/**
+	 * A published post without a shadow term should have one created on update.
+	 */
+	public function test_post_publish_to_publish_creates_missing_term(): void {
+		$post = $this->factory()->post->create(
+			array(
+				'post_type'   => 'example',
+				'post_title'  => 'Hazelnut',
+				'post_status' => 'publish',
+			)
+		);
+
+		if ( is_wp_error( $post ) ) {
+			$this->fail( 'Failed to create post.' );
+		}
+
+		$post = get_post( $post );
+		$term = get_term_by( 'slug', 'hazelnut', 'example_connect', 'OBJECT' );
+
+		if ( ! $term ) {
+			$this->fail( 'Expected term not available.' );
+		}
+
+		// Delete the shadow term to simulate the missing term condition.
+		wp_delete_term( $term->term_id, 'example_connect' );
+
+		$term = get_term_by( 'slug', 'hazelnut', 'example_connect', 'OBJECT' );
+		$this->assertFalse( $term, 'Shadow term should have been deleted.' );
+
+		// Update the post without changing its status.
+		wp_update_post( $post );
+
+		$term      = get_term_by( 'name', 'Hazelnut', 'example_connect', 'OBJECT' );
+		$term_name = ! $term ? '' : $term->name;
+
+		$this->assertEquals( 'Hazelnut', $term_name, 'A published post without a shadow term should have one created on update.' );
+	}
+
 	/**
 	 * An existing published post that has its title changed should change the
 	 * title of its shadow term.