# `MishkaCmsCore.Runtime.Resources.Changes.ReleaseBuilderHistory`
[🔗](https://github.com/mishka-group/mishka_cms_core/blob/v0.0.1/lib/mishka_cms_core/runtime/resources/__changes/release_builder_history.ex#L5)

Detaches a draft's editing history from it as the draft is deleted, so the rows survive and join
the live record's own timeline.

Add it to a destroy action on any resource the page builder keeps drafts in:

    destroy :destroy do
      change MishkaCmsCore.Runtime.Resources.Changes.ReleaseBuilderHistory
      ...
    end

## Why this is not a foreign key

It was one. `MishkaCmsCore.Runtime.PageBuilderEvent.draft_id` was a `belongs_to` to
`MishkaCmsCore.Runtime.PageDraft` with `on_delete: :nilify`, which did exactly this job — for
pages. But `source_type` names all four editable kinds and three of them keep their drafts in
tables of their own, so a change made on a layout's or an error page's draft violated that one key
and the row was refused: the History sheet was simply empty for those two sections, and the flush
logged a warning nobody reads.

A single key cannot name three tables, so the column became a plain id and the nilify moved here —
to the resource, which is the same level the constraint was at, rather than to any one caller.
That matters because a draft is deleted from several places: the picker's Delete goes through the
resource's own destroy, publishing spends the draft through
`MishkaCmsCore.Runtime.PageBuilder.Drafts.discard/3`, and the twenty-draft sweep prunes through
`prune/3`. Only the resource sees all of them.

## Best effort, deliberately

A draft the author asked to delete must go even if its history could not be released. A row left
pointing at a draft that no longer exists is invisible rather than wrong — no read names a dead
branch — so failing the delete to protect the tidiness of the log would be the worse trade.

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*Consult [api-reference.md](api-reference.md) for complete listing*