persistable_state_embeddable_clashes.md

Corner cases:

1. Registrar wants to add a migration to every registry item. Specific example: Author of Embeddable api wants to migrate base EmbeddableInput.
2. Enhancer wants to add a migration to every registry item. Specific example: Author of EnhancedEmbeddableDrilldowns wants to migrate EnhancedEmbeddableInput.
3. Registrator wants to add a migration to it's specific registry item. Example: Author of Visualize plugin wants to migrate VisualizeEmbeddableInput

Corner case 1 & avoiding clashes.

Solve for:

Base state:

interface EmbeddableInput {
  defaultTitle: string
}

Extended state:

interface VisualizeEmbeddableInput extends EmbeddableInput {
  title: string
}

Embeddable plugin wishes to migrate defaultTitle to title. It shouldn't have to know about VisualizeEmbeddableInput to do so safely (third party developers are out there that we can't collaborate with).