I'm working on the migration D7 site to D9 with all content and functionality. During the tasks of vocabularies and terms migration I found a strange bug - "No data found" and MySql errors when I'm trying to check migration status via drush or UI.
MySQL error example for "main_term" vocabulary terms migration:
SQLSTATE[42S21]: Column already exists: 1060 Duplicate column name 'machine_name': SELECT COUNT(*) AS "expression"
FROM
(SELECT DISTINCT td.*, "tv"."machine_name" AS "machine_name", 1 AS "expression"
FROM
{taxonomy_term_data} "td"
LEFT OUTER JOIN {taxonomy_vocabulary} "tv" ON td.vid = tv.vid
WHERE "tv"."machine_name" IN (:db_condition_placeholder_0)) "subquery"; Array
(
[:db_condition_placeholder_0] => main_term
)And the reason is - on D7 site installed and used https://www.drupal.org/project/taxonomy_machine_name → module that added machine_name field to taxonomy_term_data D7 table. And MySQL can't execute queries to get data with the same row names (machine_name from taxonomy_term_data and machine_name from taxonomy_vocabulary).
Just use core migration from D7 with installed taxonomy_machine_name module
In d7_taxonomy_term migration plugin define exact fields from source table instead of "td.*".
core/modules/taxonomy/src/Plugin/migrate/source/d7/Term.php
public function query() {
$query = $this->select('taxonomy_term_data', 'td')
// ->fields('td')
->fields('td', ['tid', 'vid', 'name', 'description', 'format', 'weight'])
Another solution - describe somewhere in the migration documentation "If you are using taxonomy_machine_name D7 module - before the migration you need to rename machine_name field in taxonomy_term_data table."
One more solution - ask taxonomy_machine_name maintainer to rename machine_name field in taxonomy_term_data table and include push users to update the module before upgrading Drupal.
Closed: duplicate
9.0
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
This problem was fixed in #2971457: Drupal 7 Taxonomy Term Source produces MySQL errors for machine_name → , so I am adding that as a related issue. unfortunately, there has not been a release of the module since then.
In fact, I think I will change the status of this issue from Closed (works as designed) to Closed (duplicate). And change it back to a bug report.