Revert migrations running in reverse order

Issue type:

[ ] question [x] bug report [ ] feature request [ ] documentation issue

Database system/driver:

[ ] cordova [x] mongodb [ ] mssql [ ] mysql / mariadb [ ] oracle [ ] postgres [ ] cockroachdb [ ] sqlite [ ] sqljs [ ] react-native [ ] expo

TypeORM version:

[ ] latest [ ] @next [x] 0.2.18 (or put your version here)

Steps to reproduce or a small repository showing the problem:

I created two migrations, one on August and the other today. After running this last migration I wanted to check that the down would be applied correctly. However I run into the following:

Before running revert:

> db.migrations.find()
{ "_id" : ObjectId("5d7118c2bfc3a0f771f3ea4a"), "timestamp" : 1566560354098, "name" : "UpdateContacts1566560354098" }
{ "_id" : ObjectId("5d7118c2bfc3a0f771f3ea4b"), "timestamp" : 1567689639607, "name" : "MergeConfigs1567689639607" }

Running revert:

2 migrations are already loaded in the database.
UpdateContacts1566560354098 is the last executed migration. It was executed on Fri Aug 23 2019 13:39:14 GMT+0200 (Central European Summer Time).
Now reverting it...
Migration UpdateContacts1566560354098 has been reverted successfully.

After running revert:

> db.migrations.find()
{ "_id" : ObjectId("5d7118c2bfc3a0f771f3ea4b"), "timestamp" : 1567689639607, "name" : "MergeConfigs1567689639607" }

Is this a known issue of some sort? Is there any flag or anything which I might be missing?

[RecuencoJones]

@DimaIT, I like option 1. We can add a comment to getLatestExecutedMigration with a precondition like Migration array must be sorted by descending ID.

[DimaIT]

@RecuencoJones, thanks for clarification. Now your solution looks much more reasonable to me. I think it’s makes sense to add comment describing situation with mongo ids to your code.

We could probably try to parse the timestamp or the incremental part and sort by it, but not sure if that’s the right way to fix this.

That may work, but seems kind of tricky.

I have couple more ideas:

1. We can sort migrations by id in loadExecutedMigrations. Than getLatestExecutedMigration needs just peek the last one.
2. Or if we want to keep logic related to relational databases untouched, than we can only sort migrations for mongo by _id in reverse order. getLatestExecutedMigration will pick the first migration, wich will be the latest one. I think it’s the simpliest fix that can be made.