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
47 const EXCEPTIONS_CRANELIFT: &[(&str, &str)] = &[
48 ("cranelift-bforest", "Apache-2.0 WITH LLVM-exception"),
49 ("cranelift-codegen", "Apache-2.0 WITH LLVM-exception"),
50 ("cranelift-codegen-meta", "Apache-2.0 WITH LLVM-exception"),
51 ("cranelift-codegen-shared", "Apache-2.0 WITH LLVM-exception"),
52 ("cranelift-entity", "Apache-2.0 WITH LLVM-exception"),
53 ("cranelift-frontend", "Apache-2.0 WITH LLVM-exception"),
54 ("cranelift-jit", "Apache-2.0 WITH LLVM-exception"),
55 ("cranelift-module", "Apache-2.0 WITH LLVM-exception"),
56 ("cranelift-native", "Apache-2.0 WITH LLVM-exception"),
57 ("cranelift-object", "Apache-2.0 WITH LLVM-exception"),
58 ("mach", "BSD-2-Clause"),
59 ("regalloc", "Apache-2.0 WITH LLVM-exception"),
60 ("target-lexicon", "Apache-2.0 WITH LLVM-exception"),
63 /// These are the root crates that are part of the runtime. The licenses for
64 /// these and all their dependencies *must not* be in the exception list.
65 const RUNTIME_CRATES: &[&str] = &["std", "core", "alloc", "test", "panic_abort", "panic_unwind"];
67 /// Crates whose dependencies must be explicitly permitted.
68 const RESTRICTED_DEPENDENCY_CRATES: &[&str] = &["rustc_driver", "rustc_codegen_llvm"];
70 /// Crates rustc is allowed to depend on. Avoid adding to the list if possible.
72 /// This list is here to provide a speed-bump to adding a new dependency to
73 /// rustc. Please check with the compiler team before adding an entry.
74 const PERMITTED_DEPENDENCIES: &[&str] = &[
114 "fallible-iterator", // dependency of `thorin`
161 "perf-event-open-sys",
205 "stable_deref_trait",
220 "tracing-attributes",
223 "tracing-subscriber",
227 "unic-char-property",
233 "unic-langid-macros",
234 "unic-langid-macros-impl",
236 "unicode-normalization",
245 "winapi-i686-pc-windows-gnu",
247 "winapi-x86_64-pc-windows-gnu",
248 // this is a false-positive: it's only used by rustfmt, but because it's enabled through a
249 // feature, tidy thinks it's used by rustc as well.
253 const PERMITTED_CRANELIFT_DEPENDENCIES: &[&str] = &[
261 "cranelift-codegen-meta",
262 "cranelift-codegen-shared",
264 "cranelift-frontend",
286 "winapi-i686-pc-windows-gnu",
287 "winapi-x86_64-pc-windows-gnu",
290 const FORBIDDEN_TO_HAVE_DUPLICATES: &[&str] = &[
291 // These two crates take quite a long time to build, so don't allow two versions of them
292 // to accidentally sneak into our dependency graph, in order to ensure we keep our CI times
297 /// Dependency checks.
299 /// `root` is path to the directory with the root `Cargo.toml` (for the workspace). `cargo` is path
300 /// to the cargo executable.
301 pub fn check(root: &Path, cargo: &Path, bad: &mut bool) {
302 let mut cmd = cargo_metadata::MetadataCommand::new();
303 cmd.cargo_path(cargo)
304 .manifest_path(root.join("Cargo.toml"))
305 .features(cargo_metadata::CargoOpt::AllFeatures);
306 let metadata = t!(cmd.exec());
307 let runtime_ids = compute_runtime_crates(&metadata);
308 check_exceptions(&metadata, EXCEPTIONS, runtime_ids, bad);
309 check_dependencies(&metadata, PERMITTED_DEPENDENCIES, RESTRICTED_DEPENDENCY_CRATES, bad);
310 check_crate_duplicate(&metadata, FORBIDDEN_TO_HAVE_DUPLICATES, bad);
311 check_rustfix(&metadata, bad);
313 // Check rustc_codegen_cranelift independently as it has it's own workspace.
314 let mut cmd = cargo_metadata::MetadataCommand::new();
315 cmd.cargo_path(cargo)
316 .manifest_path(root.join("compiler/rustc_codegen_cranelift/Cargo.toml"))
317 .features(cargo_metadata::CargoOpt::AllFeatures);
318 let metadata = t!(cmd.exec());
319 let runtime_ids = HashSet::new();
320 check_exceptions(&metadata, EXCEPTIONS_CRANELIFT, runtime_ids, bad);
323 PERMITTED_CRANELIFT_DEPENDENCIES,
324 &["rustc_codegen_cranelift"],
327 check_crate_duplicate(&metadata, &[], bad);
330 /// Check that all licenses are in the valid list in `LICENSES`.
332 /// Packages listed in `EXCEPTIONS` are allowed for tools.
335 exceptions: &[(&str, &str)],
336 runtime_ids: HashSet<&PackageId>,
339 // Validate the EXCEPTIONS list hasn't changed.
340 for (name, license) in exceptions {
341 // Check that the package actually exists.
342 if !metadata.packages.iter().any(|p| p.name == *name) {
345 "could not find exception package `{}`\n\
346 Remove from EXCEPTIONS list if it is no longer used.",
350 // Check that the license hasn't changed.
351 for pkg in metadata.packages.iter().filter(|p| p.name == *name) {
356 "dependency exception `{}` does not declare a license expression",
360 Some(pkg_license) => {
361 if pkg_license.as_str() != *license {
362 println!("dependency exception `{name}` license has changed");
363 println!(" previously `{license}` now `{pkg_license}`");
364 println!(" update EXCEPTIONS for the new license");
372 let exception_names: Vec<_> = exceptions.iter().map(|(name, _license)| *name).collect();
374 // Check if any package does not have a valid license.
375 for pkg in &metadata.packages {
376 if pkg.source.is_none() {
377 // No need to check local packages.
380 if !runtime_ids.contains(&pkg.id) && exception_names.contains(&pkg.name.as_str()) {
383 let license = match &pkg.license {
384 Some(license) => license,
386 tidy_error!(bad, "dependency `{}` does not define a license expression", pkg.id);
390 if !LICENSES.contains(&license.as_str()) {
391 if pkg.name == "fortanix-sgx-abi" {
392 // This is a specific exception because SGX is considered
393 // "third party". See
394 // https://github.com/rust-lang/rust/issues/62620 for more. In
395 // general, these should never be added.
398 tidy_error!(bad, "invalid license `{}` in `{}`", license, pkg.id);
403 /// Checks the dependency of `RESTRICTED_DEPENDENCY_CRATES` at the given path. Changes `bad` to
404 /// `true` if a check failed.
406 /// Specifically, this checks that the dependencies are on the `PERMITTED_DEPENDENCIES`.
407 fn check_dependencies(
409 permitted_dependencies: &[&'static str],
410 restricted_dependency_crates: &[&'static str],
413 // Check that the PERMITTED_DEPENDENCIES does not have unused entries.
414 for name in permitted_dependencies {
415 if !metadata.packages.iter().any(|p| p.name == *name) {
418 "could not find allowed package `{}`\n\
419 Remove from PERMITTED_DEPENDENCIES list if it is no longer used.",
424 // Get the list in a convenient form.
425 let permitted_dependencies: HashSet<_> = permitted_dependencies.iter().cloned().collect();
427 // Check dependencies.
428 let mut visited = BTreeSet::new();
429 let mut unapproved = BTreeSet::new();
430 for &krate in restricted_dependency_crates.iter() {
431 let pkg = pkg_from_name(metadata, krate);
433 check_crate_dependencies(&permitted_dependencies, metadata, &mut visited, pkg);
434 unapproved.append(&mut bad);
437 if !unapproved.is_empty() {
438 tidy_error!(bad, "Dependencies not explicitly permitted:");
439 for dep in unapproved {
445 /// Checks the dependencies of the given crate from the given cargo metadata to see if they are on
446 /// the list of permitted dependencies. Returns a list of disallowed dependencies.
447 fn check_crate_dependencies<'a>(
448 permitted_dependencies: &'a HashSet<&'static str>,
449 metadata: &'a Metadata,
450 visited: &mut BTreeSet<&'a PackageId>,
452 ) -> BTreeSet<&'a PackageId> {
453 // This will contain bad deps.
454 let mut unapproved = BTreeSet::new();
456 // Check if we have already visited this crate.
457 if visited.contains(&krate.id) {
461 visited.insert(&krate.id);
463 // If this path is in-tree, we don't require it to be explicitly permitted.
464 if krate.source.is_some() {
465 // If this dependency is not on `PERMITTED_DEPENDENCIES`, add to bad set.
466 if !permitted_dependencies.contains(krate.name.as_str()) {
467 unapproved.insert(&krate.id);
471 // Do a DFS in the crate graph.
472 let to_check = deps_of(metadata, &krate.id);
474 for dep in to_check {
475 let mut bad = check_crate_dependencies(permitted_dependencies, metadata, visited, dep);
476 unapproved.append(&mut bad);
482 /// Prevents multiple versions of some expensive crates.
483 fn check_crate_duplicate(
485 forbidden_to_have_duplicates: &[&str],
488 for &name in forbidden_to_have_duplicates {
489 let matches: Vec<_> = metadata.packages.iter().filter(|pkg| pkg.name == name).collect();
490 match matches.len() {
494 "crate `{}` is missing, update `check_crate_duplicate` \
495 if it is no longer used",
503 "crate `{}` is duplicated in `Cargo.lock`, \
504 it is too expensive to build multiple times, \
505 so make sure only one version appears across all dependencies",
509 println!(" * {}", pkg.id);
516 /// Returns a list of dependencies for the given package.
517 fn deps_of<'a>(metadata: &'a Metadata, pkg_id: &'a PackageId) -> Vec<&'a Package> {
518 let resolve = metadata.resolve.as_ref().unwrap();
522 .find(|n| &n.id == pkg_id)
523 .unwrap_or_else(|| panic!("could not find `{pkg_id}` in resolve"));
527 metadata.packages.iter().find(|pkg| pkg.id == dep.pkg).unwrap_or_else(|| {
528 panic!("could not find dep `{}` for pkg `{}` in resolve", dep.pkg, pkg_id)
534 /// Finds a package with the given name.
535 fn pkg_from_name<'a>(metadata: &'a Metadata, name: &'static str) -> &'a Package {
536 let mut i = metadata.packages.iter().filter(|p| p.name == name);
538 i.next().unwrap_or_else(|| panic!("could not find package `{name}` in package list"));
539 assert!(i.next().is_none(), "more than one package found for `{name}`");
543 /// Finds all the packages that are in the rust runtime.
544 fn compute_runtime_crates<'a>(metadata: &'a Metadata) -> HashSet<&'a PackageId> {
545 let resolve = metadata.resolve.as_ref().unwrap();
546 let mut result = HashSet::new();
547 for name in RUNTIME_CRATES {
548 let id = &pkg_from_name(metadata, name).id;
549 normal_deps_of_r(resolve, id, &mut result);
554 /// Recursively find all normal dependencies.
555 fn normal_deps_of_r<'a>(
556 resolve: &'a Resolve,
557 pkg_id: &'a PackageId,
558 result: &mut HashSet<&'a PackageId>,
560 if !result.insert(pkg_id) {
566 .find(|n| &n.id == pkg_id)
567 .unwrap_or_else(|| panic!("could not find `{pkg_id}` in resolve"));
568 for dep in &node.deps {
569 normal_deps_of_r(resolve, &dep.pkg, result);
573 fn check_rustfix(metadata: &Metadata, bad: &mut bool) {
574 let cargo = pkg_from_name(metadata, "cargo");
575 let compiletest = pkg_from_name(metadata, "compiletest");
576 let cargo_deps = deps_of(metadata, &cargo.id);
577 let compiletest_deps = deps_of(metadata, &compiletest.id);
578 let cargo_rustfix = cargo_deps.iter().find(|p| p.name == "rustfix").unwrap();
579 let compiletest_rustfix = compiletest_deps.iter().find(|p| p.name == "rustfix").unwrap();
580 if cargo_rustfix.version != compiletest_rustfix.version {
583 "cargo's rustfix version {} does not match compiletest's rustfix version {}\n\
584 rustfix should be kept in sync, update the cargo side first, and then update \
585 compiletest along with cargo.",
586 cargo_rustfix.version,
587 compiletest_rustfix.version