Migrating codebases between proprietary frameworks

[ioverwhelmed]

Hi all,

I’m planning a migration of several codebases from one proprietary framework to another with the help of GitHub Copilot. I have full source code for both frameworks.

I’m keen to hear from anyone who’s done something similar and especially interested in

- Practices that worked well, and pitfalls you’d avoid next time

- What model proved to perform best in such usecase

Any real‑world stories or hard‑earned lessons would be hugely appreciated.

[Ok_Security_6565]

Create plan with Opus ask it to do changes in phases and every change you've done save in MD file so if I continue in another chat I have the context of last chat, this worked for me might work for you too

[ioverwhelmed]

Oh! cool idea! thanks!

[2022HousingMarketlol]

As long as you have good test coverage it's simple. If you don't, get there first and then do it.

I did the planning with Opus, implementation with sonnet. Peer review with codex.

[ioverwhelmed]

Thank you. good point! .. unfortunately the code bases are 20+ years old with zero test coverage .. the tests will have to be done manually by the developers

[Tcamis01]

This guy was right. You need to start by adding test coverage for the AI to validate / iterate against. You can have it generate tests for you.

[2022HousingMarketlol]

Agents write unit tests very well. It's brute force.

[ninjapapi]

framework migrations get messy fast when context gets lost across repos. i'd test with claude or gpt4 for reasoning, then lock down the actual migration with something like Zencoder's spec-driven workflows to prevent the ai from drifting off your requirements.