Hello I am very excited about the new Apollo Kotlin and I wa

Question

Hello I am very excited about the new Apollo Kotlin and I was looking at what it would take to upgrade the project from work from v2 to v3 but unfortunately it seems like a migration would be extremely difficult from what I could tell so far Even if using `codegenModels` set to `compat` or with `useVersion2Compat ` which I think that it might do the same thing there would be thousands of changes to go through in the project the vast majority of them would be just removing function invocations from GQL fields quite a few of them would be changing how polymorphic fragments are accessed and a lot of mutation and query builders need to be changed too to constructor invocations It would be a huuuuge time sink to do all of this changes in one go so I was wondering is it possible to have v2 and v3 running side by side in the same app but using the same SQL cache So that we can keep the old code using Apollo Android and slowly migrate to Apollo Kotlin This would actually solve another issue for us we have a lot of custom code that allows us to pass references to fragments from one activity to another and then observe for updates and we would have to rewrite most of it but again it s hard to do it in one go Thankfully `ApolloStore readFragment ` from v3 does a lot of this already smile I imagine that even if it would be possible to have two instances writing to and reading from the same database observing the cache for updates using ` watch ` won t trigger any updates if the write was done by the other instance isn t it Is there any hope to ease the migration for such a complex project I want the new and fancy test builders haha Sorry for the wall of text

mbonnin · Answer

Using apollo2 and apollo3 side by side is possible but sharing the cache is not unfortunately Mainly because locking would have to be shared and like you said `watch` would come with challenges too

mbonnin · Answer

From what you re saying looks like you re migrating from java models `compat` models are compatible with Kotlin codegen <https github com apollographql apollo kotlin issues 3359|with a few exceptions> but have a lot more differences with Java models

mbonnin · Answer

If that s the case you can as an intermediate step enable Kotlin models in your apollo2 codebase `generateKotlinModels set true `

mbonnin · Answer

Another option is to write a script that does this automatically Most of the changes are automatic enough so that they could be scripted

Eduard Boloș · Answer

Yes we re still using Java models disappointed Indeed migrating first to Kotlin models sounds like it would ease the migration Thanks for the pointers Martin slightly smiling face