bug: migrate schema with multiple connected storages

[jameshclrk]

This PR contains:

A test case for #7009

Describe the problem you have without this PR

If a collection has multiple connected storages, for example with multiple replication handlers, there is a race condition where the underlying collection used for the migration is removed because the name is the same (see sqlite-trial error).

I haven't tried all storages, but I have seen it on memory and sqlite-trial.

error with npm run test:node:memory

     RxError (DM4):

Error message: Migration errored
Error code: DM4
Find out more about this error here: https://rxdb.info/errors.html?console=errors#DM4

--------------------
Parameters:
collection: "mycollection"
error: {
  "name": "Error",
  "message": "removed",
  "rxdb": null,
  "parameters": null,
  "extensions": null,
  "code": null,
  "url": null,
  "stack": "Error: removed \n     at ensureNotRemoved (file:///Users/jamesclark/code/rxdb/src/plugins/storage-memory/memory-helper.ts:36:15) \n     at RxStorageInstanceMemory.oldBulkWrite [as bulkWrite] (file:///Users/jamesclark/code/rxdb/src/plugins/storage-memory/rx-storage-instance-memory.ts:108:9) \n     at RxStorageInstanceMemory.bulkWrite (file:///Users/jamesclark/code/rxdb/src/plugin-helpers.ts:129:29) \n     at file:///Users/jamesclark/code/rxdb/src/replication-protocol/upstream.ts:441:48"
}

error with npm run test:node:sqlite-trial

Error: no such table: rx-migration-state-meta-mycollection-1-0
    at Object.all (file:///Users/jamesclark/code/rxdb/src/plugins/storage-sqlite/sqlite-basics-helpers.ts:94:33)
    at sqliteTransaction.databaseName (file:///Users/jamesclark/code/rxdb/src/plugins/storage-sqlite/sqlite-storage-instance.ts:128:32)
    at file:///Users/jamesclark/code/rxdb/src/plugins/storage-sqlite/sqlite-helpers.ts:179:31
{
    "code": "ERR_SQLITE_ERROR",
    "errcode": 1,
    "errstr": "SQL logic error"
}

Todos

• Tests
• Documentation
• Typings
• Changelog

[pubkey]

You have to close the old database before creating a new one with a changed schema.

[jameshclrk]

You have to close the old database before creating a new one with a changed schema.

I added an await db.close() before creating the second database and still see an error thrown.

[pubkey]

@jameshclrk Thank you for the test case, this helps a lot. Could reproduce your error, working on a fix..