1 //! Checks the licenses of third-party dependencies.
3 use cargo_metadata::{Metadata, Package, PackageId, Resolve};
4 use std::collections::{BTreeSet, HashSet};
7 /// These are licenses that are allowed for all crates, including the runtime,
9 const LICENSES: &[&str] = &[
16 "Apache-2.0 WITH LLVM-exception OR Apache-2.0 OR MIT", // wasi license
21 "0BSD OR MIT OR Apache-2.0", // adler license
22 "Zlib OR Apache-2.0 OR MIT", // tinyvec
25 /// These are exceptions to Rust's permissive licensing policy, and
26 /// should be considered bugs. Exceptions are only allowed in Rust
27 /// tooling. It is _crucial_ that no exception crates be dependencies
28 /// of the Rust runtime (std/test).
29 const EXCEPTIONS: &[(&str, &str)] = &[
30 ("mdbook", "MPL-2.0"), // mdbook
31 ("openssl", "Apache-2.0"), // cargo, mdbook
32 ("colored", "MPL-2.0"), // rustfmt
33 ("ordslice", "Apache-2.0"), // rls
34 ("ryu", "Apache-2.0 OR BSL-1.0"), // rls/cargo/... (because of serde)
35 ("bytesize", "Apache-2.0"), // cargo
36 ("im-rc", "MPL-2.0+"), // cargo
37 ("sized-chunks", "MPL-2.0+"), // cargo via im-rc
38 ("bitmaps", "MPL-2.0+"), // cargo via im-rc
39 ("instant", "BSD-3-Clause"), // rustc_driver/tracing-subscriber/parking_lot
40 ("snap", "BSD-3-Clause"), // rustc
41 ("fluent-langneg", "Apache-2.0"), // rustc (fluent translations)
42 ("self_cell", "Apache-2.0"), // rustc (fluent translations)
43 // FIXME: this dependency violates the documentation comment above:
44 ("fortanix-sgx-abi", "MPL-2.0"), // libstd but only for `sgx` target
45 ("dunce", "CC0-1.0"), // cargo (dev dependency)
46 ("similar", "Apache-2.0"), // cargo (dev dependency)
47 ("normalize-line-endings", "Apache-2.0"), // cargo (dev dependency)
50 const EXCEPTIONS_CRANELIFT: &[(&str, &str)] = &[
51 ("cranelift-bforest", "Apache-2.0 WITH LLVM-exception"),
52 ("cranelift-codegen", "Apache-2.0 WITH LLVM-exception"),
53 ("cranelift-codegen-meta", "Apache-2.0 WITH LLVM-exception"),
54 ("cranelift-codegen-shared", "Apache-2.0 WITH LLVM-exception"),
55 ("cranelift-entity", "Apache-2.0 WITH LLVM-exception"),
56 ("cranelift-frontend", "Apache-2.0 WITH LLVM-exception"),
57 ("cranelift-jit", "Apache-2.0 WITH LLVM-exception"),
58 ("cranelift-module", "Apache-2.0 WITH LLVM-exception"),
59 ("cranelift-native", "Apache-2.0 WITH LLVM-exception"),
60 ("cranelift-object", "Apache-2.0 WITH LLVM-exception"),
61 ("mach", "BSD-2-Clause"),
62 ("regalloc", "Apache-2.0 WITH LLVM-exception"),
63 ("target-lexicon", "Apache-2.0 WITH LLVM-exception"),
66 /// These are the root crates that are part of the runtime. The licenses for
67 /// these and all their dependencies *must not* be in the exception list.
68 const RUNTIME_CRATES: &[&str] = &["std", "core", "alloc", "test", "panic_abort", "panic_unwind"];
70 /// Crates whose dependencies must be explicitly permitted.
71 const RESTRICTED_DEPENDENCY_CRATES: &[&str] = &["rustc_driver", "rustc_codegen_llvm"];
73 /// Crates rustc is allowed to depend on. Avoid adding to the list if possible.
75 /// This list is here to provide a speed-bump to adding a new dependency to
76 /// rustc. Please check with the compiler team before adding an entry.
77 const PERMITTED_DEPENDENCIES: &[&str] = &[
117 "fallible-iterator", // dependency of `thorin`
164 "perf-event-open-sys",
207 "stable_deref_trait",
222 "tracing-attributes",
225 "tracing-subscriber",
229 "unic-char-property",
235 "unic-langid-macros",
236 "unic-langid-macros-impl",
238 "unicode-normalization",
247 "winapi-i686-pc-windows-gnu",
249 "winapi-x86_64-pc-windows-gnu",
250 // this is a false-positive: it's only used by rustfmt, but because it's enabled through a
251 // feature, tidy thinks it's used by rustc as well.
255 const PERMITTED_CRANELIFT_DEPENDENCIES: &[&str] = &[
263 "cranelift-codegen-meta",
264 "cranelift-codegen-shared",
266 "cranelift-frontend",
288 "winapi-i686-pc-windows-gnu",
289 "winapi-x86_64-pc-windows-gnu",
292 const FORBIDDEN_TO_HAVE_DUPLICATES: &[&str] = &[
293 // These two crates take quite a long time to build, so don't allow two versions of them
294 // to accidentally sneak into our dependency graph, in order to ensure we keep our CI times
299 /// Dependency checks.
301 /// `root` is path to the directory with the root `Cargo.toml` (for the workspace). `cargo` is path
302 /// to the cargo executable.
303 pub fn check(root: &Path, cargo: &Path, bad: &mut bool) {
304 let mut cmd = cargo_metadata::MetadataCommand::new();
305 cmd.cargo_path(cargo)
306 .manifest_path(root.join("Cargo.toml"))
307 .features(cargo_metadata::CargoOpt::AllFeatures);
308 let metadata = t!(cmd.exec());
309 let runtime_ids = compute_runtime_crates(&metadata);
310 check_exceptions(&metadata, EXCEPTIONS, runtime_ids, bad);
311 check_dependencies(&metadata, PERMITTED_DEPENDENCIES, RESTRICTED_DEPENDENCY_CRATES, bad);
312 check_crate_duplicate(&metadata, FORBIDDEN_TO_HAVE_DUPLICATES, bad);
313 check_rustfix(&metadata, bad);
315 // Check rustc_codegen_cranelift independently as it has it's own workspace.
316 let mut cmd = cargo_metadata::MetadataCommand::new();
317 cmd.cargo_path(cargo)
318 .manifest_path(root.join("compiler/rustc_codegen_cranelift/Cargo.toml"))
319 .features(cargo_metadata::CargoOpt::AllFeatures);
320 let metadata = t!(cmd.exec());
321 let runtime_ids = HashSet::new();
322 check_exceptions(&metadata, EXCEPTIONS_CRANELIFT, runtime_ids, bad);
325 PERMITTED_CRANELIFT_DEPENDENCIES,
326 &["rustc_codegen_cranelift"],
329 check_crate_duplicate(&metadata, &[], bad);
332 /// Check that all licenses are in the valid list in `LICENSES`.
334 /// Packages listed in `EXCEPTIONS` are allowed for tools.
337 exceptions: &[(&str, &str)],
338 runtime_ids: HashSet<&PackageId>,
341 // Validate the EXCEPTIONS list hasn't changed.
342 for (name, license) in exceptions {
343 // Check that the package actually exists.
344 if !metadata.packages.iter().any(|p| p.name == *name) {
347 "could not find exception package `{}`\n\
348 Remove from EXCEPTIONS list if it is no longer used.",
352 // Check that the license hasn't changed.
353 for pkg in metadata.packages.iter().filter(|p| p.name == *name) {
358 "dependency exception `{}` does not declare a license expression",
362 Some(pkg_license) => {
363 if pkg_license.as_str() != *license {
364 println!("dependency exception `{name}` license has changed");
365 println!(" previously `{license}` now `{pkg_license}`");
366 println!(" update EXCEPTIONS for the new license");
374 let exception_names: Vec<_> = exceptions.iter().map(|(name, _license)| *name).collect();
376 // Check if any package does not have a valid license.
377 for pkg in &metadata.packages {
378 if pkg.source.is_none() {
379 // No need to check local packages.
382 if !runtime_ids.contains(&pkg.id) && exception_names.contains(&pkg.name.as_str()) {
385 let license = match &pkg.license {
386 Some(license) => license,
388 tidy_error!(bad, "dependency `{}` does not define a license expression", pkg.id);
392 if !LICENSES.contains(&license.as_str()) {
393 if pkg.name == "fortanix-sgx-abi" {
394 // This is a specific exception because SGX is considered
395 // "third party". See
396 // https://github.com/rust-lang/rust/issues/62620 for more. In
397 // general, these should never be added.
400 tidy_error!(bad, "invalid license `{}` in `{}`", license, pkg.id);
405 /// Checks the dependency of `RESTRICTED_DEPENDENCY_CRATES` at the given path. Changes `bad` to
406 /// `true` if a check failed.
408 /// Specifically, this checks that the dependencies are on the `PERMITTED_DEPENDENCIES`.
409 fn check_dependencies(
411 permitted_dependencies: &[&'static str],
412 restricted_dependency_crates: &[&'static str],
415 // Check that the PERMITTED_DEPENDENCIES does not have unused entries.
416 for name in permitted_dependencies {
417 if !metadata.packages.iter().any(|p| p.name == *name) {
420 "could not find allowed package `{}`\n\
421 Remove from PERMITTED_DEPENDENCIES list if it is no longer used.",
426 // Get the list in a convenient form.
427 let permitted_dependencies: HashSet<_> = permitted_dependencies.iter().cloned().collect();
429 // Check dependencies.
430 let mut visited = BTreeSet::new();
431 let mut unapproved = BTreeSet::new();
432 for &krate in restricted_dependency_crates.iter() {
433 let pkg = pkg_from_name(metadata, krate);
435 check_crate_dependencies(&permitted_dependencies, metadata, &mut visited, pkg);
436 unapproved.append(&mut bad);
439 if !unapproved.is_empty() {
440 tidy_error!(bad, "Dependencies not explicitly permitted:");
441 for dep in unapproved {
447 /// Checks the dependencies of the given crate from the given cargo metadata to see if they are on
448 /// the list of permitted dependencies. Returns a list of disallowed dependencies.
449 fn check_crate_dependencies<'a>(
450 permitted_dependencies: &'a HashSet<&'static str>,
451 metadata: &'a Metadata,
452 visited: &mut BTreeSet<&'a PackageId>,
454 ) -> BTreeSet<&'a PackageId> {
455 // This will contain bad deps.
456 let mut unapproved = BTreeSet::new();
458 // Check if we have already visited this crate.
459 if visited.contains(&krate.id) {
463 visited.insert(&krate.id);
465 // If this path is in-tree, we don't require it to be explicitly permitted.
466 if krate.source.is_some() {
467 // If this dependency is not on `PERMITTED_DEPENDENCIES`, add to bad set.
468 if !permitted_dependencies.contains(krate.name.as_str()) {
469 unapproved.insert(&krate.id);
473 // Do a DFS in the crate graph.
474 let to_check = deps_of(metadata, &krate.id);
476 for dep in to_check {
477 let mut bad = check_crate_dependencies(permitted_dependencies, metadata, visited, dep);
478 unapproved.append(&mut bad);
484 /// Prevents multiple versions of some expensive crates.
485 fn check_crate_duplicate(
487 forbidden_to_have_duplicates: &[&str],
490 for &name in forbidden_to_have_duplicates {
491 let matches: Vec<_> = metadata.packages.iter().filter(|pkg| pkg.name == name).collect();
492 match matches.len() {
496 "crate `{}` is missing, update `check_crate_duplicate` \
497 if it is no longer used",
505 "crate `{}` is duplicated in `Cargo.lock`, \
506 it is too expensive to build multiple times, \
507 so make sure only one version appears across all dependencies",
511 println!(" * {}", pkg.id);
518 /// Returns a list of dependencies for the given package.
519 fn deps_of<'a>(metadata: &'a Metadata, pkg_id: &'a PackageId) -> Vec<&'a Package> {
520 let resolve = metadata.resolve.as_ref().unwrap();
524 .find(|n| &n.id == pkg_id)
525 .unwrap_or_else(|| panic!("could not find `{pkg_id}` in resolve"));
529 metadata.packages.iter().find(|pkg| pkg.id == dep.pkg).unwrap_or_else(|| {
530 panic!("could not find dep `{}` for pkg `{}` in resolve", dep.pkg, pkg_id)
536 /// Finds a package with the given name.
537 fn pkg_from_name<'a>(metadata: &'a Metadata, name: &'static str) -> &'a Package {
538 let mut i = metadata.packages.iter().filter(|p| p.name == name);
540 i.next().unwrap_or_else(|| panic!("could not find package `{name}` in package list"));
541 assert!(i.next().is_none(), "more than one package found for `{name}`");
545 /// Finds all the packages that are in the rust runtime.
546 fn compute_runtime_crates<'a>(metadata: &'a Metadata) -> HashSet<&'a PackageId> {
547 let resolve = metadata.resolve.as_ref().unwrap();
548 let mut result = HashSet::new();
549 for name in RUNTIME_CRATES {
550 let id = &pkg_from_name(metadata, name).id;
551 normal_deps_of_r(resolve, id, &mut result);
556 /// Recursively find all normal dependencies.
557 fn normal_deps_of_r<'a>(
558 resolve: &'a Resolve,
559 pkg_id: &'a PackageId,
560 result: &mut HashSet<&'a PackageId>,
562 if !result.insert(pkg_id) {
568 .find(|n| &n.id == pkg_id)
569 .unwrap_or_else(|| panic!("could not find `{pkg_id}` in resolve"));
570 for dep in &node.deps {
571 normal_deps_of_r(resolve, &dep.pkg, result);
575 fn check_rustfix(metadata: &Metadata, bad: &mut bool) {
576 let cargo = pkg_from_name(metadata, "cargo");
577 let compiletest = pkg_from_name(metadata, "compiletest");
578 let cargo_deps = deps_of(metadata, &cargo.id);
579 let compiletest_deps = deps_of(metadata, &compiletest.id);
580 let cargo_rustfix = cargo_deps.iter().find(|p| p.name == "rustfix").unwrap();
581 let compiletest_rustfix = compiletest_deps.iter().find(|p| p.name == "rustfix").unwrap();
582 if cargo_rustfix.version != compiletest_rustfix.version {
585 "cargo's rustfix version {} does not match compiletest's rustfix version {}\n\
586 rustfix should be kept in sync, update the cargo side first, and then update \
587 compiletest along with cargo.",
588 cargo_rustfix.version,
589 compiletest_rustfix.version