Issue #2616282 by peter.walter, mikeryan, chx, alexpott: error creating...

Issue #2616282 by peter.walter, mikeryan, chx, alexpott: error creating migrate_map table with mysql 5.7.9

core/modules/migrate/src/Plugin/MigrateSourceInterface.php

@@ -44,10 +44,14 @@ public function prepareRow(Row $row);
   public function __toString();
 
   /**
-   * Get the source ids.
+   * Defines the source fields uniquely identifying a source row. None of these
+   * fields should contain a NULL value - if necessary, use prepareRow() or
+   * hook_migrate_prepare_row() to rewrite NULL values to appropriate empty
+   * values (such as '' or 0).
    *
    * @return array
-   *   The source ids.
+   *   Array keyed by source field name, with values being a schema array
+   *   describing the field (such as ['type' => 'string]).
    */
   public function getIds();
 

core/modules/migrate/src/Plugin/migrate/id_map/Sql.php

@@ -287,6 +287,7 @@ protected function ensureTables() {
       foreach ($this->migration->getSourcePlugin()->getIds() as $id_definition) {
         $mapkey = 'sourceid' . $count++;
         $source_id_schema[$mapkey] = $this->getFieldSchema($id_definition);
+        $source_id_schema[$mapkey]['not null'] = TRUE;
 
         // With InnoDB, utf8mb4-based primary keys can't be over 191 characters.
         // Use ASCII-based primary keys instead.