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tokio-rs / prost

PROST! a Protocol Buffers implementation for the Rust Language
Apache License 2.0
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chore: Update internal crates to Rust edition 2021 #1039

Closed caspermeijn closed 5 months ago

caspermeijn commented 5 months ago

The published crates were already using edition 2021. Update all internal crates as well.

Also add a new tests-2018 crate that runs all tests using edition 2018.

gibbz00 commented 5 months ago

Hii, two things 😊

1) Why are we testing against old editions?

https://doc.rust-lang.org/edition-guide/editions/#editions-do-not-split-the-ecosystem

The most important rule for editions is that crates in one edition can interoperate seamlessly with crates compiled in other editions. This ensures that the decision to migrate to a newer edition is a "private one" that the crate can make without affecting others.

2) Maybe the test-2018 addition should be made into a separate PR so that we can discuss 1) separately without blocking this one for #1036

caspermeijn commented 5 months ago
  1. Why are we testing against old editions?

I am not sure, but I assume this is because we generate code that must be compatible with older and newer editions. For example, in some test code is a cfg_if that adds extern crate statements for 2015 edition only.

Well, I see two options:

  1. Add the tests-2018 crate. I mostly did this because the tests-2015 crate exists. I am not sure what the added value is over just running the tests with the oldest edition.
  2. Update main tests crate to edition 2021 and don't explicitly test 2018. I am fine with that, as I think the difference between 2018 and 2021 is small enough to not cause any problems.

What do you think is best?

gibbz00 commented 5 months ago

we generate code that must be compatible with older and newer editions.

Ahh, I see. Makes perfect sense.

Also agree that it's worth testing against the 2018 edition given that it's quite easy.