tari lint

Checks a template crate for issues that hurt the published WASM binary or the developer experience. Every check except the Rust lints prints the exact fix, and most can be applied automatically with --fix.

tari lint [PATH] [OPTIONS]

Aliases: tari lints, tari check.

Arguments

Argument	Description
[PATH]	Path to the template crate directory, or its Cargo.toml (default: .)

Options

Option	Description
--fix	Apply the suggested fix for every issue that can be fixed automatically
--no-clippy	Skip the cargo clippy run and only check the manifests
-D, --deny-warnings	Exit non-zero on warnings and suggestions, not just errors

Checks

Code	Severity	Checks	--fix
rust::clippy	error / warning	Runs cargo clippy --target wasm32-unknown-unknown and reports its diagnostics	Runs cargo clippy --fix
cargo::crate-type	error / warning	[lib] crate-type is exactly ["cdylib"] — extra types such as rlib are compiled and linked in, bloating the binary	✅
cargo::release-profile	warning	[profile.release] declares the size optimizations (opt-level, lto, codegen-units, panic, strip)	✅
cargo::test-runtime-profile	suggestion	Wasmer/Cranelift are optimized in dev builds, so template tests are not ~10x slower. Only checked when the crate has tests	✅
template::metadata	warning / suggestion	description and [package.metadata.tari-template] fields are filled in	❌ — only you know the values; run tari template init
template::metadata-build	warning	tari_ootle_template_build is a build dependency and build.rs calls TemplateMetadataBuilder	✅ (unless an unrelated build.rs already exists)
template::byte-vec	warning	Vec<u8> in CBOR-encoded template types — fields of the types a #[template] module encodes (and of any type deriving an encoding trait), plus the arguments and return types of template functions	❌ — the fix rewrites your source

Cargo only honours [profile.*] in the workspace root manifest, so profile checks read — and --fix writes — the workspace root Cargo.toml when the template is a workspace member.

tari build and tari publish already pass the release profile settings via cargo --config, so cargo::release-profile matters for anyone building the crate with plain cargo build --release.

template::byte-vec

Vec<u8> CBOR-encodes as an array of integers — Array(Int(1), Int(2), ...) — costing up to two bytes per byte plus per-element decoding, instead of the dedicated CBOR byte string. Component state is stored, and call arguments are sent, in that encoding, so it shows up in substate size and transaction size.

Use Bytes from the template prelude, which encodes as a byte string:

use tari_template_lib::prelude::*;

#[template]
mod my_template {
    use super::*;

    pub struct MyTemplate {
        payload: Bytes,
    }

    impl MyTemplate {
        pub fn new(payload: Bytes) -> Self {
            Self { payload }
        }
    }
}

A field can also keep its Vec<u8> and pick the byte encoding with an attribute — #[cbor(with = "minicbor::bytes")] for the minicbor derives a #[template] module injects, or #[serde(with = "tari_template_lib::types::bytes")] for a serde-derived type. Function arguments and return types have no attribute to fall back on, so Bytes is the only fix there.

The check skips fields that already choose a codec (#[cbor(with = ..)], #[serde(with = ..)], or a skip), non-pub items in a #[template] module (the macro does not derive a codec for those), and #[template(skip_cbor_derives)] modules, where the derives you write yourself are what it looks at instead.

Exit codes

0 when no errors were found, 1 when any error was found — or any warning with --deny-warnings. Suitable for CI.

Examples

Check the current crate

tari lint

Output:

⚠️ warning[cargo::crate-type]: `crate-type` also contains `rlib` — every extra crate type is
   compiled and linked in, bloating the published binary
   --> Cargo.toml [lib]
   help:
       In Cargo.toml, keep only the dynamic library:

       [lib]
       crate-type = ["cdylib"]
   (fixable with `tari lint --fix`)

Summary: 0 error(s), 1 warning(s), 0 suggestion(s)

Apply the automatic fixes

tari lint --fix

In CI

Fail on any finding, without needing a clippy install:

tari lint --deny-warnings --no-clippy