Issue #2827897 by quietone, danflanagan8, mikelutz, smustgrave, mikeryan,...

Issue #2827897 by quietone, danflanagan8, mikelutz, smustgrave, mikeryan, osopolar, xurizaemon, benjifisher: Update documentation for handling dots in the static_map plugin

core/modules/migrate/src/Plugin/migrate/process/StaticMap.php

@@ -29,6 +29,13 @@
  * - default_value: (optional) The value to return if the source is not found in
  *   the map array.
  *
+ * While this plugin supports map key values which contain a dot (.), Drupal
+ * configuration export does not export keys which contain a dot. Be careful
+ * when using this feature with migrations that are stored as configuration
+ * entities. These entities cannot contain keys with a dot. In this case,
+ * additional manipulation with either custom or contrib process plugins is
+ * needed.
+ *
  * Examples:
  *
  * If the value of the source property 'foo' is 'from' then the value of the
@@ -134,11 +141,6 @@
  *       1: bar
  * @endcode
  *
- * Mapping from a string which contains a period is not supported. A custom
- * process plugin can be written to handle this kind of a transformation.
- * Another option which may be feasible in certain use cases is to first pass
- * the value through the machine_name process plugin.
- *
  * @see https://www.drupal.org/project/drupal/issues/2827897
  * @see \Drupal\migrate\Plugin\MigrateProcessInterface
  */

core/modules/migrate/tests/src/Unit/process/StaticMapTest.php

@@ -113,4 +113,14 @@ public function testWithNullSource() {
     $this->assertSame('mapped NULL', $value);
   }
 
+  /**
+   * Tests when there is a dot in a map key.
+   */
+  public function testMapDotInKey(): void {
+    $configuration['map']['foo.bar'] = 'baz';
+    $this->plugin = new StaticMap($configuration, 'map', []);
+    $value = $this->plugin->transform('foo.bar', $this->migrateExecutable, $this->row, 'destination_property');
+    $this->assertSame('baz', $value);
+  }
+
 }