Side note:

My initial attempt was to update to edition 2024, which I successfully did. However, when running the CI locally, I was blocked by the MSRV, which doesn’t support edition2024 yet. it was only stabilized in Rust 1.85.

https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#edition-2024

For the role crates, MSRV doesn’t really matter since they’re just applications built on top of our protocol layer.

if a dependency is attached to some MSRV, doesn't that mean the crate that depends on it is also bound to that MSRV?

in other words: what happens if I try to build pool_sv2 with rustc 1.74.0?

Thanks for this! Could you run cargo fix --edition once and check if the lock file changes? Also, it'd be great if you can take a quick look to see if any new features in the edition might actually help us. For the role crates, MSRV doesn’t really matter since they’re just applications built on top of our protocol layer. But for the protocol crates, we do need to stick to an MSRV mainly to guarantee that downstream users can compile them with any stable compiler starting from 1.75. That also means we shouldn't use any syntax or features that aren’t supported in 1.75.

@Shourya742, thanks for the review!

I’ve completed the migration using cargo fix --edition, and it didn’t require any changes to the lock file.

I also took a quick look at the changes in the 2021 edition and didn’t notice anything particularly useful for our case.
Edition Guide - Rust 2021

The primary reason for opening this PR is that I noticed some mismatched editions between roles, with some on 2018 and others on 2021.

This is more of a housekeeping thing.

For the role crates, MSRV doesn’t really matter since they’re just applications built on top of our protocol layer.

if a dependency is attached to some MSRV, doesn't that mean the crate that depends on it is also bound to that MSRV?

in other words: what happens if I try to build pool_sv2 with rustc 1.74.0?

@plebhash, just a practical response:

$ pwd && cargo +1.74.0 build
/home/lucasbalieiro/Projects/stratum/roles/pool
error: package `config v0.14.1` cannot be built because it requires rustc 1.75.0 or newer, while the currently active rustc version is 1.74.0
Either upgrade to rustc 1.75.0 or newer, or use
cargo update config@0.14.1 --precise ver
where `ver` is the latest version of `config` supporting rustc 1.74.0

As you can see, it throws an error about the config package, which is used by config_helpers. So, I guess the answer to your question is: yes, if a dependency has an MSRV requirement, it does impact the crates that depend on it.

For the role crates, MSRV doesn’t really matter since they’re just applications built on top of our protocol layer.

if a dependency is attached to some MSRV, doesn't that mean the crate that depends on it is also bound to that MSRV?

in other words: what happens if I try to build pool_sv2 with rustc 1.74.0?

Yes, the Rust version used to build these top-level crates should be greater than or equal to the highest MSRV among their dependencies. So, the role crates should be built with rustc >= 1.75.0. Any version above 1.75 will work, and you're free to use features introduced in those versions even if they wouldn't compile on 1.75. What I meant is: code that compiles with 1.75 will also compile with 1.80, but the reverse isn't necessarily true features from 1.80 may not be compatible with the 1.75 compiler.

LGTM, but I'm curious to know: have you tried to bump also protocol crates' editions during your testing?

LGTM, but I'm curious to know: have you tried to bump also protocol crates' editions during your testing?

Yes, I ran cargo fix --edition and tested the changes locally. Everything works as expected. No additional modifications were needed aside from updating the edition in Cargo.toml.

Would you like me to include this in the current PR?

Why not?
For coherence among our entire codebase I think it would make sense to have 2021 edition also there.

Why not? For coherence among our entire codebase I think it would make sense to have 2021 edition also there.

protocols edition bumped in: upgrade protocols to rust edition 2021

We still have stratum-common, integration_tests_sv2, buffer_sv2, and buffer-fuzz with 2018 edition.

We still have stratum-common, integration_tests_sv2, buffer_sv2, and buffer-fuzz with 2018 edition.

@GitGab19, the buffer ones are a bit tricky.

buffer-fuzz relies on a specific toolchain that doesn't support the 2021 edition, which in turn prevents buffer_sv2 from being upgraded as well.

I added the commits for stratum-common and integration-tests: a7db02b feaf4c6

Can you elaborate more on the toolchain? Which toolchain is used there?

Can you elaborate more on the toolchain? Which toolchain is used there?

Apologies 😅, while writing up the explanation, I realized that the buffer-fuzz toolchain is actually using nightly, whereas I had been running cargo fix --edition with the stable toolchain.

$ cat utils/buffer/fuzz/rust-toolchain.toml 
[toolchain]
channel = "nightly-2020-04-06" #here is the toolchain for the buffer-fuzz

I've just updated the buffer crate accordingly.