Node Migration Race Condition

[Jotschi]

Situation

1. Create Node
2. Update schema (with failing migration)
3. Update schema again (no error since no other node needs migration)
4. Invoke /api/v1/:project/branches/:branchUuid/migrateSchemas

or

1. Create Node
2. Update Schema (with failing migration)
3. Unassign schema from project
4. Invoke /api/v1/:project/branches/:branchUuid/migrateSchemas

Issue

An error should be observed because the preparation would create indices for older schema versions which the NodeIndexHandler rejects (since it deems them to no longer be active).

Solutions

• Ignore NodeIndexHandler checks and create the index.
• Update NodeIndexHandler to also check for older not migrated nodes (could be a performance issue since all NGFC or SchemaVersions would need to be checked)