The Variable (variable) migrate source plugin has been given a new variables_no_row_if_missing configuration option. From now on, if any of the variables listed below this new variables_no_row_if_missing key are missing from the source Drupal database, the plugin will return zero rows.
The pre-existing variables configuration continues to operate as before: the variables listed under that key do not have to exist in the source Drupal database, if they are missing the plugin will return a row with an empty value for the variable.
Examples:
With this configuration, the source will return one row even when the filter_fallback_format variable isn't available:
source:
plugin: variable
variables:
- filter_fallback_format
With this configuration, the source will return one row if the file_public_path variable is available, and zero if it isn't:
source:
plugin: variable
variables:
- file_private_path
- file_temporary_path
variables_no_row_if_missing:
- file_public_path
The variables that are guaranteed to exist (variables) and the ones that aren't (variables_no_row_if_missing) are always merged together. All of the following configurations are valid:
source:
plugin: variable
variables:
- book_child_type
- book_block_mode
- book_allowed_types
variables_no_row_if_missing:
- book_child_type
- book_block_mode
- book_allowed_types
source:
plugin: variable
variables:
- book_child_type
- book_block_mode
variables_no_row_if_missing:
- book_allowed_types
source:
plugin: variable
variables_no_row_if_missing:
- book_child_type
- book_block_mode
- book_allowed_types
