rust_crate
Resolved third-party Cargo package lowered into a Rust library target.
Description
Represents a sourced package from a resolved Cargo lockfile as a normal Once graph target. rust_crate compiles to an rlib and emits the same rust_crate provider shape consumed by rust_library and rust_binary deps.
Attributes
| Attribute | Type | Required | Default | Description |
|---|---|---|---|---|
package_name | string | yes | Original Cargo package name | |
version | string | yes | Resolved Cargo package version | |
crate_name | string | no | target name | Rust crate name passed to rustc; - and . are rewritten as _ when omitted |
crate_root | string | no | src/lib.rs | Package-relative library root |
edition | string | no | 2021 | Rust edition passed to rustc |
features | list<string> | no | [] | Cargo feature names lowered to --cfg=feature=... flags |
crate_features | list<string> | no | [] | Bazel-compatible alias for features |
target | string | no | host target | Rust target triple passed to rustc --target |
env | map<string, string> | no | {} | Environment variables for rustc, matching Buck2's env attribute |
rustc_env | map<string, string> | no | {} | Bazel-compatible rustc environment variables |
rustc_env_files | list<string> | no | [] | Files with NAME=value entries merged into the rustc environment before env and rustc_env |
rustc_flags | list<string> | no | [] | Additional rustc flags appended after Once-managed flags |
cap_lints | string | no | empty | Optional rustc lint cap passed as --cap-lints; generated Cargo dependencies use allow |
linker | string | no | empty | Optional linker path passed as -C linker=...; defaults to cc for host Unix binary-like targets and to the Android NDK clang wrapper for Android targets when available |
linker_flags | list<string> | no | [] | Additional linker flags lowered to -C link-arg=... |
native_linkopts | list<string> | no | [] | Shared Rust compatibility attribute for native-producing Rust target kinds |
exported_linker_flags | list<string> | no | [] | Buck-compatible alias for native linker flags propagated to downstream native consumers |
exported_post_linker_flags | list<string> | no | [] | Buck-compatible propagated linker flags appended after normal exported linker flags |
linker_script | string | no | empty | Package-relative linker script passed to the linker and included in the compile action inputs |
android_abi | string | no | inferred | Android ABI directory for dynamic library outputs, such as arm64-v8a |
android_api | int | no | 23 | Android API level used to select the NDK clang wrapper for Android targets |
android_ndk | string | no | ANDROID_NDK_HOME | Android NDK root used to find clang wrapper linkers |
data | list<string> | no | [] | Runtime data file globs propagated to downstream Rust binaries and tests |
compile_data | list<string> | no | [] | Bazel-compatible compile-time data file globs included in the rustc action inputs |
crate_aliases | map<string, string> | no | {} | Map dependency label, package name, or crate name to the local extern crate name |
aliases | map<string, string> | no | {} | Bazel-compatible alias map from dependency label or crate name to local extern crate name |
named_deps | map<string, string> | no | {} | Buck-compatible alias map from local extern crate name to dependency label or crate name |
cargo_package | string | no | empty | Cargo package name used to select direct external deps from a cargo_dependencies dependency set. Defaults to CARGO_PKG_NAME when present |
build_script | string | no | empty | Package-relative Cargo build script path run before rustc; common cargo:rustc-* stdout directives are consumed, dependency cargo:rustc-link-search outputs are replayed downstream, and direct dependency links metadata is consumed |
source | string | no | Cargo source identifier | |
checksum | string | no | Cargo.lock checksum for registry packages |
Accepted but unsupported attributes: default_deps, doc_deps, doc_env, doc_link_style, doc_linker_flags, doc_named_deps, link_deps, link_style, mapped_srcs, proc_macro_deps, rpath, runtime_dependency_handling, and rustdoc_flags. Non-empty values fail validation.
Dependency Edges
| Edge | Accepts | Description |
|---|---|---|
deps | rust_crate, rust_proc_macro, rust_dependency_set | Resolved Cargo package dependencies |
Providers
The target emits rust_crate.
Capabilities
| Capability | Output groups |
|---|---|
build | rlib |
Outputs
| Output | Location |
|---|---|
| Rust library | .once/out/<target>/lib<crate_name>-<metadata>.rlib |
Example
toml
[[target]]
name = "itoa-1.0.14"
kind = "rust_crate"
srcs = ["vendor/itoa-1.0.14/src/**/*.rs"]
[target.attrs]
package_name = "itoa"
crate_name = "itoa"
version = "1.0.14"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "..."
crate_root = "vendor/itoa-1.0.14/src/lib.rs"
edition = "2021"