src/tools/clippy/clippy_lints/src/multiple_crate_versions.rs

   1 //! lint on multiple versions of a crate being used
   2
   3 use crate::utils::{run_lints, span_lint};
   4 use rustc_hir::def_id::LOCAL_CRATE;
   5 use rustc_hir::{Crate, CRATE_HIR_ID};
   6 use rustc_lint::{LateContext, LateLintPass};
   7 use rustc_session::{declare_lint_pass, declare_tool_lint};
   8 use rustc_span::source_map::DUMMY_SP;
   9
  10 use cargo_metadata::{DependencyKind, Node, Package, PackageId};
  11 use if_chain::if_chain;
  12 use itertools::Itertools;
  13
  14 declare_clippy_lint! {
  15     /// **What it does:** Checks to see if multiple versions of a crate are being
  16     /// used.
  17     ///
  18     /// **Why is this bad?** This bloats the size of targets, and can lead to
  19     /// confusing error messages when structs or traits are used interchangeably
  20     /// between different versions of a crate.
  21     ///
  22     /// **Known problems:** Because this can be caused purely by the dependencies
  23     /// themselves, it's not always possible to fix this issue.
  24     ///
  25     /// **Example:**
  26     /// ```toml
  27     /// # This will pull in both winapi v0.3.x and v0.2.x, triggering a warning.
  28     /// [dependencies]
  29     /// ctrlc = "=3.1.0"
  30     /// ansi_term = "=0.11.0"
  31     /// ```
  32     pub MULTIPLE_CRATE_VERSIONS,
  33     cargo,
  34     "multiple versions of the same crate being used"
  35 }
  36
  37 declare_lint_pass!(MultipleCrateVersions => [MULTIPLE_CRATE_VERSIONS]);
  38
  39 impl LateLintPass<'_> for MultipleCrateVersions {
  40     fn check_crate(&mut self, cx: &LateContext<'_>, _: &Crate<'_>) {
  41         if !run_lints(cx, &[MULTIPLE_CRATE_VERSIONS], CRATE_HIR_ID) {
  42             return;
  43         }
  44
  45         let metadata = unwrap_cargo_metadata!(cx, MULTIPLE_CRATE_VERSIONS, true);
  46         let local_name = cx.tcx.crate_name(LOCAL_CRATE).as_str();
  47         let mut packages = metadata.packages;
  48         packages.sort_by(|a, b| a.name.cmp(&b.name));
  49
  50         if_chain! {
  51             if let Some(resolve) = &metadata.resolve;
  52             if let Some(local_id) = packages
  53                 .iter()
  54                 .find_map(|p| if p.name == *local_name { Some(&p.id) } else { None });
  55             then {
  56                 for (name, group) in &packages.iter().group_by(|p| p.name.clone()) {
  57                     let group: Vec<&Package> = group.collect();
  58
  59                     if group.len() <= 1 {
  60                         continue;
  61                     }
  62
  63                     if group.iter().all(|p| is_normal_dep(&resolve.nodes, local_id, &p.id)) {
  64                         let mut versions: Vec<_> = group.into_iter().map(|p| &p.version).collect();
  65                         versions.sort();
  66                         let versions = versions.iter().join(", ");
  67
  68                         span_lint(
  69                             cx,
  70                             MULTIPLE_CRATE_VERSIONS,
  71                             DUMMY_SP,
  72                             &format!("multiple versions for dependency `{}`: {}", name, versions),
  73                         );
  74                     }
  75                 }
  76             }
  77         }
  78     }
  79 }
  80
  81 fn is_normal_dep(nodes: &[Node], local_id: &PackageId, dep_id: &PackageId) -> bool {
  82     fn depends_on(node: &Node, dep_id: &PackageId) -> bool {
  83         node.deps.iter().any(|dep| {
  84             dep.pkg == *dep_id
  85                 && dep
  86                     .dep_kinds
  87                     .iter()
  88                     .any(|info| matches!(info.kind, DependencyKind::Normal))
  89         })
  90     }
  91
  92     nodes
  93         .iter()
  94         .filter(|node| depends_on(node, dep_id))
  95         .any(|node| node.id == *local_id || is_normal_dep(nodes, local_id, &node.id))
  96 }