About Inheritance of Snapshot Labels

Snapshot labels are inherited by all files that are referenced by a document with a snapshot label applied.

If a DITA map with a snapshot references a structured document, any children of that structured document in the map hierarchy also inherit the snapshot when processed with the label. Inheritance also applies to referenced graphics and any reuse targets, such as conrefs, entities, or external files.

For example, a DITA map has a topicref to a concept topic, and the concept topic references a graphic. If you attach a snapshot label with a timestamp of March 1 to the DITA map, and process using that snapshot label, the DITA map is processed as it existed on March 1, and the referenced concept topic and the graphic are processed as they existed on March 1 as well.

The inheritance of an snapshot can be overridden by applying the same snapshot label on a lower-level object with a different timestamp. The ability to override the timestamp of a snapshot on objects that would otherwise inherit the original date allows you to reprocess a release of a previous document version with a few minor changes even if updates for a subsequent release have begun.

So in the above example, suppose you updated the concept topic and revised the graphic it references on April 10. You then apply the snapshot label to the concept topic with a date of April 15. When you process the DITA map using the snapshot label, the concept topic (and the graphic it references) is processed as it existed on April 15. All other objects in the DITA map are processed as they existed on March 1, even if they have been updated after March 1.

Note: A structured document that inherits a snapshot label from a parent map or structured document may also be referenced in a different context by another map or structured document with a different snapshot label or no snapshot label. In this case, during processing in the new context, no inheritance occurs from the snapshot label on the first parent map or structured document. Relying on inheritance of the snapshot label instead of adding the label explicitly to an object provides flexibility for documents that are reused in multiple contexts.

If you don't want to rely on inheritance of snapshot labels, in dialogs where you apply the label, you can select the option to add the label explicitly to referenced objects.