How to make orml-traits and orml-tokens compatible with sp-io version 7.0.0 in a Substrate project?

Question

I am working on a Substrate project and want to use the orml-traits and orml-tokens crates in my custom pallet. I have added these crates to my Cargo.toml:

orml-tokens = { git = "https://github.com/open-web3-stack/open-runtime-module-library.git", default-features = false, version = "0.4.0" }
orml-traits = { git = "https://github.com/open-web3-stack/open-runtime-module-library.git", default-features = false, version = "0.4.0" }

My project uses sp-io version 7.0.0, but I'm facing a dependency conflict:

error[E0152]: duplicate lang item in crate `sp_io` (which `sp_application_crypto` depends on): `panic_impl`.
|
= note: the lang item is first defined in crate `sp_io` (which `frame_support` depends on)
= note: first definition in `sp_io` loaded from /home/kianoush/projects/music-chain/target/debug/wbuild/kitchensink-runtime/target/wasm32-unknown-unknown/release/deps/libsp_io-3f01c569c1bdc73f.rmeta
= note: second definition in `sp_io` loaded from /home/kianoush/projects/music-chain/target/debug/wbuild/kitchensink-runtime/target/wasm32-unknown-unknown/release/deps/libsp_io-a6d4512a0b6fd246.rmeta

  For more information about this error, try `rustc --explain E0152`.
  warning: `pallet-dex` (lib) generated 2 warnings
  error: could not compile `pallet-dex` due to previous error; 2 warnings emitted
  warning: build failed, waiting for other jobs to finish...
warning: build failed, waiting for other jobs to finish...

How can I make orml-traits and orml-tokens compatible with sp-io version 7.0.0 in my Substrate project?

Answer 1

First and foremost, make sure you're not using the open-runtime-module-library from crates.io - it is super old

You can patch all the Substrate dependencies to make sure they are the same throughout your project.

For example, Acala is currently using polkadot-v0.9.38:

# substrate
frame-executive = { git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.38", default-features = false }
frame-support = { git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.38", default-features = false }
....

• https://github.com/AcalaNetwork/Acala/blob/65b2ba1f97e96ff55afbc389acfa667c421bc797/runtime/karura/Cargo.toml#L16-L54

And you can see they use a patch to override the substrate dependency with a specific revision which you can pick but make sure it has sp-io v7.0.0:

[patch."https://github.com/paritytech/substrate"]
frame-benchmarking = { git = "https://github.com/paritytech//substrate", rev = "18bb7c7c841b101c19a8d1881b893ae8e37de460" }
frame-benchmarking-cli = { git = "https://github.com/paritytech//substrate", rev = "18bb7c7c841b101c19a8d1881b893ae8e37de460" }
....

• https://github.com/AcalaNetwork/Acala/blob/65b2ba1f97e96ff55afbc389acfa667c421bc797/Cargo.toml#L128-L283

And you can see that in open-runtime-module-library there is a polkadot-v0.9.38 branch that has a patch:

[patch.'https://github.com/paritytech/substrate']
frame-benchmarking = { git = "https://github.com/paritytech//substrate", rev = "18bb7c7c841b101c19a8d1881b893ae8e37de460" }
frame-support = { git = "https://github.com/paritytech//substrate", rev = "18bb7c7c841b101c19a8d1881b893ae8e37de460" }
....

• https://github.com/open-web3-stack/open-runtime-module-library/blob/241d5cdc98cca53b8cf990853943c9ae1193a70e/Cargo.dev.toml#L39-L89

Notice that the revisions from the orml library and Acala's substrate dependencies match up: 18bb7c7c841b101c19a8d1881b893ae8e37de460 == 18bb7c7c841b101c19a8d1881b893ae8e37de460

Your project should now work.

If you're not familiar with how cargo's patch works:

• https://doc.rust-lang.org/cargo/reference/overriding-dependencies.html

Specifically what we used above is this:

• https://doc.rust-lang.org/cargo/reference/overriding-dependencies.html#overriding-repository-url