Add DB schema check and instructions for updating the schema version #219
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| .sort((a, b) => (a.name < b.name ? 1 : -1)), | ||
| ); | ||
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| const hasSchemaChanged = async (db: Dexie) => { |
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Would be nice to have some tests for this. Feels like it could be a finicky process.
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will do! that's an easy add, it's just a string comparison.
| await db.open(); | ||
| if (await hasSchemaChanged(db)) { | ||
| throw new Error( | ||
| `The local DB schema has changed and must be upgraded. |
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Are we only changing the schema on major version's? Seems like that is a requirement, given it requires an explicit user migration to update their schema version
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that's a good question and something i've thought about a lot. sometimes adding a new feature requires a schema change, but adding to the schema doesn't usually create an issue. it's only when updating/removing an existing schema that requires a new version.
that being said, having to add/update a component prop for an SDK update could be considered a breaking change in that it does require a code change. however, it's not an involved refactor, usually just a single character change. is that a breaking change? i could be convinced that it is... or isn't.
ideally, this is something that we would manage internally so that developers don't have to think about it. how we're currently managing the schema for content type caching makes this more difficult since we're not storing all versions of the schema over time.
i'm definitely open to going down this route. it was something i originally considered but went with a simpler solution at the time.
| import App from "./App.tsx"; | ||
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| export const MyApp: React.FC = () => ( | ||
| <XMTPProvider dbVersion={2}> |
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What happens when I increment this version? Is it going to wipe out my entire local DB and force re-create it?
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just informs Dexie about the new schema so it understands how to work with the data. the current DB and its data should remain intact.
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different error when version is set to 2:
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when you set the dbVersion to 2, did you have another tab open with the app? i haven't encountered that error yet, but this issue may provide some insight.
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no other tab was open in firefox, but the same app dev instance was open in chrome - do you think this messed up the firefox dexie database?
this is the actual error in the console:
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that's strange. chrome shouldn't affect firefox and vice versa.
Summary
When the local DB schema is updated as part of a code change in the React SDK, client apps must upgrade their schema version to include the changes. To help with this, instructions and a DB schema check have been added. If the schema check detects change, it will throw an error that informs app developers to upgrade the schema version.