rust-clippy/clippy_lints/src/cargo/mod.rs

mod common_metadata;
mod feature_name;
mod multiple_crate_versions;
mod wildcard_dependencies;

use cargo_metadata::MetadataCommand;
use clippy_utils::diagnostics::span_lint;
use clippy_utils::is_lint_allowed;
use rustc_hir::hir_id::CRATE_HIR_ID;
use rustc_lint::{LateContext, LateLintPass, Lint};
use rustc_session::impl_lint_pass;
use rustc_span::DUMMY_SP;

declare_clippy_lint! {
    /// ### What it does
    /// Checks to see if all common metadata is defined in
    /// `Cargo.toml`. See: https://rust-lang-nursery.github.io/api-guidelines/documentation.html#cargotoml-includes-all-common-metadata-c-metadata
    ///
    /// ### Why is this bad?
    /// It will be more difficult for users to discover the
    /// purpose of the crate, and key information related to it.
    ///
    /// ### Example
    /// ```toml
    /// # This `Cargo.toml` is missing a description field:
    /// [package]
    /// name = "clippy"
    /// version = "0.0.212"
    /// repository = "https://github.com/rust-lang/rust-clippy"
    /// readme = "README.md"
    /// license = "MIT OR Apache-2.0"
    /// keywords = ["clippy", "lint", "plugin"]
    /// categories = ["development-tools", "development-tools::cargo-plugins"]
    /// ```
    ///
    /// Should include a description field like:
    ///
    /// ```toml
    /// # This `Cargo.toml` includes all common metadata
    /// [package]
    /// name = "clippy"
    /// version = "0.0.212"
    /// description = "A bunch of helpful lints to avoid common pitfalls in Rust"
    /// repository = "https://github.com/rust-lang/rust-clippy"
    /// readme = "README.md"
    /// license = "MIT OR Apache-2.0"
    /// keywords = ["clippy", "lint", "plugin"]
    /// categories = ["development-tools", "development-tools::cargo-plugins"]
    /// ```
    #[clippy::version = "1.32.0"]
    pub CARGO_COMMON_METADATA,
    cargo,
    "common metadata is defined in `Cargo.toml`"
}

declare_clippy_lint! {
    /// ### What it does
    /// Checks for feature names with prefix `use-`, `with-` or suffix `-support`
    ///
    /// ### Why is this bad?
    /// These prefixes and suffixes have no significant meaning.
    ///
    /// ### Example
    /// ```toml
    /// # The `Cargo.toml` with feature name redundancy
    /// [features]
    /// default = ["use-abc", "with-def", "ghi-support"]
    /// use-abc = []  // redundant
    /// with-def = []   // redundant
    /// ghi-support = []   // redundant
    /// ```
    ///
    /// Use instead:
    /// ```toml
    /// [features]
    /// default = ["abc", "def", "ghi"]
    /// abc = []
    /// def = []
    /// ghi = []
    /// ```
    ///
    #[clippy::version = "1.57.0"]
    pub REDUNDANT_FEATURE_NAMES,
    cargo,
    "usage of a redundant feature name"
}

declare_clippy_lint! {
    /// ### What it does
    /// Checks for negative feature names with prefix `no-` or `not-`
    ///
    /// ### Why is this bad?
    /// Features are supposed to be additive, and negatively-named features violate it.
    ///
    /// ### Example
    /// ```toml
    /// # The `Cargo.toml` with negative feature names
    /// [features]
    /// default = []
    /// no-abc = []
    /// not-def = []
    ///
    /// ```
    /// Use instead:
    /// ```toml
    /// [features]
    /// default = ["abc", "def"]
    /// abc = []
    /// def = []
    ///
    /// ```
    #[clippy::version = "1.57.0"]
    pub NEGATIVE_FEATURE_NAMES,
    cargo,
    "usage of a negative feature name"
}

declare_clippy_lint! {
    /// ### What it does
    /// Checks to see if multiple versions of a crate are being
    /// used.
    ///
    /// ### Why is this bad?
    /// This bloats the size of targets, and can lead to
    /// confusing error messages when structs or traits are used interchangeably
    /// between different versions of a crate.
    ///
    /// ### Known problems
    /// Because this can be caused purely by the dependencies
    /// themselves, it's not always possible to fix this issue.
    ///
    /// ### Example
    /// ```toml
    /// # This will pull in both winapi v0.3.x and v0.2.x, triggering a warning.
    /// [dependencies]
    /// ctrlc = "=3.1.0"
    /// ansi_term = "=0.11.0"
    /// ```
    #[clippy::version = "pre 1.29.0"]
    pub MULTIPLE_CRATE_VERSIONS,
    cargo,
    "multiple versions of the same crate being used"
}

declare_clippy_lint! {
    /// ### What it does
    /// Checks for wildcard dependencies in the `Cargo.toml`.
    ///
    /// ### Why is this bad?
    /// [As the edition guide says](https://rust-lang-nursery.github.io/edition-guide/rust-2018/cargo-and-crates-io/crates-io-disallows-wildcard-dependencies.html),
    /// it is highly unlikely that you work with any possible version of your dependency,
    /// and wildcard dependencies would cause unnecessary breakage in the ecosystem.
    ///
    /// ### Example
    /// ```toml
    /// [dependencies]
    /// regex = "*"
    /// ```
    #[clippy::version = "1.32.0"]
    pub WILDCARD_DEPENDENCIES,
    cargo,
    "wildcard dependencies being used"
}

pub struct Cargo {
    pub ignore_publish: bool,
}

impl_lint_pass!(Cargo => [
    CARGO_COMMON_METADATA,
    REDUNDANT_FEATURE_NAMES,
    NEGATIVE_FEATURE_NAMES,
    MULTIPLE_CRATE_VERSIONS,
    WILDCARD_DEPENDENCIES
]);

impl LateLintPass<'_> for Cargo {
    fn check_crate(&mut self, cx: &LateContext<'_>) {
        static NO_DEPS_LINTS: &[&Lint] = &[
            CARGO_COMMON_METADATA,
            REDUNDANT_FEATURE_NAMES,
            NEGATIVE_FEATURE_NAMES,
            WILDCARD_DEPENDENCIES,
        ];
        static WITH_DEPS_LINTS: &[&Lint] = &[MULTIPLE_CRATE_VERSIONS];

        if !NO_DEPS_LINTS
            .iter()
            .all(|&lint| is_lint_allowed(cx, lint, CRATE_HIR_ID))
        {
            match MetadataCommand::new().no_deps().exec() {
                Ok(metadata) => {
                    common_metadata::check(cx, &metadata, self.ignore_publish);
                    feature_name::check(cx, &metadata);
                    wildcard_dependencies::check(cx, &metadata);
                },
                Err(e) => {
                    for lint in NO_DEPS_LINTS {
                        span_lint(cx, lint, DUMMY_SP, &format!("could not read cargo metadata: {e}"));
                    }
                },
            }
        }

        if !WITH_DEPS_LINTS
            .iter()
            .all(|&lint| is_lint_allowed(cx, lint, CRATE_HIR_ID))
        {
            match MetadataCommand::new().exec() {
                Ok(metadata) => {
                    multiple_crate_versions::check(cx, &metadata);
                },
                Err(e) => {
                    for lint in WITH_DEPS_LINTS {
                        span_lint(cx, lint, DUMMY_SP, &format!("could not read cargo metadata: {e}"));
                    }
                },
            }
        }
    }
}