Solana: What is the best way to CPI between programs that use two different Anchor versions?

CPI Between Programs Using Anchor Versions: A Step-by-Step Guide to Raydium-CP-Swap

As an Anchor developer, you are probably familiar with the concept of Cross-Program (CP) swapping, which allows you to run different programs on top of the Anchor blockchain without downgrading. However, when using a library like “raydium-cp-swap”, it is essential to understand how CPI (Cross-Program Interoperability) is done between programs that use two different Anchor versions.

Problem: Downgrading

When you run a program with an older Anchor version on top of another program that is on top of a newer version, you may encounter issues due to differences in their architectures and software. This is where downgrading your program comes in. However, if you are using “raydium-cp-swap”, which uses Anchor version 0.29.0 (code), you may be concerned about upgrading your program.

Solution: CPI without Downgrade

To solve this problem, we explore a few approaches to CPI between programs that use two different Anchor versions:

• Update the newer program: Update a program that uses an older Anchor version (e.g. 0.30.1) to match or be compatible with the newer Anchor version (0.29.0). This requires careful consideration of the software architecture and compatibility issues.

• Use a compatibility layer: Implement a compatibility layer, such as a custom library or service, that eliminates the differences between Anchor versions. This way, you can ensure that your program interacts with both versions without worrying about downgrading.

• Optimize for compatibility: If neither of the above options is possible, optimize your program to be compatible with different Anchor versions. For example, you can rewrite your code in a way that is more suitable for specific Anchor versions.

Implementation

In this article, we will focus on the first approach: updating a newer program to match or be compatible with an older Anchor version. Here is an example of how you can upgrade a Code program using the “raydium-cp-swap” command:

use raydium_cp_swap::{AnchorVersion, Program};
use anchor_lang::program::ProgramResult;
fn main() -> ProgramResult {
let mut provider = AnchorStore::new(&Key::from_static(b"program_name"));
provider.set_next_version(0.29.0);
// Upgrade the program to match or be compatible with version 0.30.1
provider.upgrade::("upgrade", "YourProgram")?;
give updated_program = provider.get();
// Now you can run your program in version 0.30.1 using the updated library
Ok (())
}

Conclusion

CPI between programs using two different Anchor versions can be challenging. However, by investigating updates and compatibility levels or optimizing compatibility, you can ensure a smooth transition to new Anchor versions. Remember to weigh the tradeoffs of updating your program against the potential performance impacts.

If you are looking for more information on implementing raydium-cp-swap or finding compatibility solutions, feel free to ask!