syn 1.x and 2.x both used in sea-query

[sartak]

Description

I'm shipping a crate that uses sea-query, but getting a warning that multiple versions of syn are being pulled in.

I'm sure it wouldn't be trivial to upgrade sea-query-derive to syn 2.x, but it would make downstream compile times faster, (possibly) binaries smaller, and reduce warnings that are not feasibly fixable.

Steps to Reproduce

1. cargo new --lib foo
2. cd foo
3. add #![warn(clippy::cargo)] to the top of src/lib.rs
4. cargo add sea-query
5. cargo clippy

Expected Behavior

Adding sea-query to my project is clippy::cargo-clean.

Actual Behavior

Adding sea-query to my project generates a new clippy::cargo warning;

warning: multiple versions for dependency `syn`: 1.0.109, 2.0.35
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#multiple_crate_versions

Reproduces How Often

Every time.

Versions

λ cargo tree | grep sea-
└── sea-query v0.30.1
    └── sea-query-derive v0.4.0 (proc-macro)

Additional Information

sea-query-derive depends on syn 1.x here:

sea-query/sea-query-derive/Cargo.toml

Line 18 in b80f14e

syn = { version = "1", default-features = false, features = ["parsing", "proc-macro", "derive", "printing"] }

where syn 2.x is pulled in via inherent and thiserror.

[tyt2y3]

Thanks for raising this.

Yeah, SeaORM went through an exercise of upgrading to syn2. It was an involving process, and it left us just there without touching SeaQuery. Contribution is of course welcome.

However, I would like to point out this is an ecosystem problem. Unless every crate in a dependency tree upgrades to syn2, it will be pretty hard to avoid having two syn.

[lillianrubyrose]

I wouldn't mind taking a look at this in my spare time. Need more proc macro practice anyway