I’m writing migrations to import source data as paragraphs.

Here is the main migration (which is working):

id: resource_chapter_section_text label: Import content from the resource.body column in the source database as chapter_section_text paragraphs. migration_group: redacted_web source:   plugin: resource_chapter_section_text   key: migrate_web process:   # a real value will be placed here by the resource_chapter_section_text_content migration   # we have to do it in a second pass to avoid creating a circular dependency   field_text/value:     plugin: default_value     default_value: 'placeholder'   field_text/format:     plugin: default_value     default_value: 'plain_text' destination:   plugin: entity_reference_revisions:paragraph   default_bundle: chapter_section_text dependencies:   enforced:     module:       - redacted_migration 

Note that field_text is being populated with a placeholder value. That’s because the source data for that field needs to be transformed in certain ways before I can import it. In order to avoid a circular dependency, this transformation must be done after all chapter_section_text paragraphs have been imported.

So, I’m trying to write a second migration, which will do a second pass over the same source table, and will update the paragraphs that were created by the first migration. Here is that second migration:

id: resource_chapter_section_text_content label: Converts the contents of resource_chapter_section_text paragraphs from pseudo-Markdown to HTML, and updates link URLs. migration_group: redacted_web source:   plugin: resource_chapter_section_text_content   key: migrate_web process:   id:     plugin: migration_lookup     migration: resource_chapter_section_text     source: section_id   field_text/value: content_converted   field_text/format:     plugin: default_value     default_value: 'full_html' destination:   plugin: entity_reference_revisions:paragraph   default_bundle: chapter_section_text   overwrite_properties:     - field_text/value     - field_text/format migration_dependencies:   required:     - resource_chapter_section_text     - collection_term     - document_node     - theme     - resource dependencies:   enforced:     module:       - redacted_migration 

As you can see, I’m specifying the existing paragraph ID, and using destination.overwrite_properties to specify the fields to be updated.

I’ve successfully used the same technique in another migration to update existing nodes. However, it’s not working here. Migrate seems to be trying to create new paragraphs instead. I get this error:

[error]  DrupalCoreDatabaseIntegrityConstraintViolationException: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '3829' for key 'PRIMARY': INSERT INTO "paragraphs_item" ("id", "revision_id", "type", "uuid", "langcode") VALUES (:db_insert_placeholder_0, :db_insert_placeholder_1, :db_insert_placeholder_2, :db_insert_placeholder_3, :db_insert_placeholder_4); 

Is it possible to do this with paragraph entities? Am I doing something wrong?

Thanks!