Auto merge of #157721 - clubby789:test-lint-machinery, r=<try>

compiletest: Add testing for lint machinery at runtime


try-job: x86_64-gnu-stable
try-job: dist-x86_64-msvc

Author: bors

Cargo.lock

@@ -879,6 +879,13 @@ dependencies = [
  "windows 0.61.3",
 ]
 
+[[package]]
+name = "compiletest-lint-driver"
+version = "0.1.0"
+dependencies = [
+ "libloading 0.9.0",
+]
+
 [[package]]
 name = "console"
 version = "0.16.3"

Cargo.toml

@@ -15,6 +15,7 @@ members = [
   "src/tools/clippy/clippy_dev",
   "src/tools/collect-license-metadata",
   "src/tools/compiletest",
+  "src/tools/compiletest-lint-driver",
   "src/tools/coverage-dump",
   "src/tools/features-status-dump",
   "src/tools/generate-copyright",

src/bootstrap/src/core/build_steps/check.rs

@@ -877,6 +877,13 @@ tool_check_step!(Compiletest {
     default: false,
 });
 
+tool_check_step!(CompiletestLintDriver {
+    path: "src/tools/compiletest-lint-driver",
+    mode: Mode::ToolRustcPrivate,
+    allow_features: "rustc_private",
+    default: false,
+});
+
 // As with compiletest, rustdoc-gui-test is automatically built when running
 // relevant tests. So being able to check it is mainly useful for people
 // working on on rustdoc-gui-test itself, or on its compiletest dependency.

src/bootstrap/src/core/build_steps/clippy.rs

@@ -498,6 +498,7 @@ lint_any!(
     Clippy, "src/tools/clippy", "clippy", Mode::ToolRustcPrivate;
     CollectLicenseMetadata, "src/tools/collect-license-metadata", "collect-license-metadata", Mode::ToolTarget;
     Compiletest, "src/tools/compiletest", "compiletest", Mode::ToolTarget;
+    CompiletestLintDriver, "src/tools/compiletest-lint-driver", "compiletest-lint-driver", Mode::ToolRustcPrivate;
     CoverageDump, "src/tools/coverage-dump", "coverage-dump", Mode::ToolTarget;
     Jsondocck, "src/tools/jsondocck", "jsondocck", Mode::ToolTarget;
     Jsondoclint, "src/tools/jsondoclint", "jsondoclint", Mode::ToolTarget;

src/bootstrap/src/core/build_steps/test.rs

@@ -2058,6 +2058,12 @@ NOTE: if you're sure you want to do this, please open an issue as to why. In the
             builder.ensure(compile::Rustc::new(test_compiler, target));
         }
 
+        let lint_driver_compiler = query_compiler.unwrap_or(test_compiler);
+        if suite == "ui-fulldeps" {
+            builder.std(lint_driver_compiler, target);
+            builder.std(lint_driver_compiler, lint_driver_compiler.host);
+        }
+
         if suite == "debuginfo" {
             builder.ensure(dist::DebuggerScripts {
                 sysroot: builder.sysroot(test_compiler).to_path_buf(),
@@ -2096,6 +2102,17 @@ NOTE: if you're sure you want to do this, please open an issue as to why. In the
         cmd.arg("--compile-lib-path").arg(builder.rustc_libdir(test_compiler));
         cmd.arg("--run-lib-path").arg(builder.sysroot_target_libdir(test_compiler, target));
         cmd.arg("--rustc-path").arg(builder.rustc(test_compiler));
+        if suite == "ui-fulldeps" {
+            let lint_driver: PathBuf = builder
+                .ensure(tool::CompiletestLintDriver {
+                    compiler: test_compiler,
+                    target: test_compiler.host,
+                })
+                .tool_path;
+            cmd.arg("--rustc-lint-driver-path").arg(lint_driver);
+            cmd.arg("--rustc-lint-driver-lib-path").arg(builder.rustc_libdir(lint_driver_compiler));
+            cmd.arg("--rustc-lint-driver-sysroot").arg(builder.sysroot(lint_driver_compiler));
+        }
         if let Some(query_compiler) = query_compiler {
             cmd.arg("--query-rustc-path").arg(builder.rustc(query_compiler));
         }

src/bootstrap/src/core/build_steps/tool.rs

@@ -634,6 +634,47 @@ impl Step for ErrorIndex {
     }
 }
 
+#[derive(Debug, Clone, Hash, PartialEq, Eq)]
+pub struct CompiletestLintDriver {
+    pub compiler: Compiler,
+    pub target: TargetSelection,
+}
+
+impl Step for CompiletestLintDriver {
+    type Output = ToolBuildResult;
+    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
+        run.path("src/tools/compiletest-lint-driver")
+    }
+
+    fn make_run(run: RunConfig<'_>) {
+        run.builder.ensure(CompiletestLintDriver {
+            compiler: run.builder.compiler(0, run.builder.config.host_target),
+            target: run.target,
+        });
+    }
+
+    fn run(self, builder: &Builder<'_>) -> ToolBuildResult {
+        builder.std(self.compiler, self.target);
+        builder.ensure(compile::Rustc::new(self.compiler, self.target));
+        builder.ensure(ToolBuild {
+            build_compiler: self.compiler,
+            target: self.target,
+            tool: "compiletest-lint-driver",
+            mode: Mode::ToolRustcPrivate,
+            path: "src/tools/compiletest-lint-driver",
+            source_type: SourceType::InTree,
+            extra_features: Vec::new(),
+            allow_features: "rustc_private",
+            cargo_args: Vec::new(),
+            artifact_kind: ToolArtifactKind::Binary,
+        })
+    }
+
+    fn metadata(&self) -> Option<StepMetadata> {
+        Some(StepMetadata::build("CompiletestLintDriver", self.target).built_by(self.compiler))
+    }
+}
+
 #[derive(Debug, Clone, Hash, PartialEq, Eq)]
 pub struct RemoteTestServer {
     pub build_compiler: Compiler,

src/bootstrap/src/core/builder/mod.rs

@@ -776,6 +776,7 @@ impl<'a> Builder<'a> {
                 tool::Linkchecker,
                 tool::CargoTest,
                 tool::Compiletest,
+                tool::CompiletestLintDriver,
                 tool::RemoteTestServer,
                 tool::RemoteTestClient,
                 tool::RustInstaller,
@@ -815,6 +816,7 @@ impl<'a> Builder<'a> {
                 clippy::CodegenGcc,
                 clippy::CollectLicenseMetadata,
                 clippy::Compiletest,
+                clippy::CompiletestLintDriver,
                 clippy::CoverageDump,
                 clippy::Jsondocck,
                 clippy::Jsondoclint,
@@ -848,6 +850,7 @@ impl<'a> Builder<'a> {
                 check::Bootstrap,
                 check::RunMakeSupport,
                 check::Compiletest,
+                check::CompiletestLintDriver,
                 check::RustdocGuiTest,
                 check::FeaturesStatusDump,
                 check::CoverageDump,

src/bootstrap/src/core/builder/tests.rs

@@ -2098,6 +2098,7 @@ mod snapshot {
         [test] compiletest-assembly-llvm 1 <host>
         [test] compiletest-incremental 1 <host>
         [test] compiletest-debuginfo 1 <host>
+        [build] rustc 0 <host> -> CompiletestLintDriver 1 <host>
         [test] compiletest-ui-fulldeps 1 <host>
         [build] rustdoc 1 <host>
         [test] compiletest-rustdoc-html 1 <host>
@@ -2171,12 +2172,13 @@ mod snapshot {
         insta::assert_snapshot!(
             ctx.config("test")
                 .args(&["ui", "ui-fulldeps", "run-make", "rustdoc-html", "rustdoc-gui", "incremental"])
-                .render_steps(), @r"
+                .render_steps(), @"
         [build] llvm <host>
         [build] rustc 0 <host> -> rustc 1 <host>
         [build] rustc 1 <host> -> std 1 <host>
         [build] rustc 0 <host> -> Compiletest 1 <host>
         [test] compiletest-ui 1 <host>
+        [build] rustc 0 <host> -> CompiletestLintDriver 1 <host>
         [test] compiletest-ui-fulldeps 1 <host>
         [build] rustc 0 <host> -> RunMakeSupport 1 <host>
         [build] rustdoc 1 <host>
@@ -2195,7 +2197,7 @@ mod snapshot {
             ctx.config("test")
                 .args(&["ui", "ui-fulldeps", "run-make", "rustdoc-html", "rustdoc-gui", "incremental"])
                 .stage(2)
-                .render_steps(), @r"
+                .render_steps(), @"
         [build] llvm <host>
         [build] rustc 0 <host> -> rustc 1 <host>
         [build] rustc 1 <host> -> std 1 <host>
@@ -2204,6 +2206,7 @@ mod snapshot {
         [build] rustc 0 <host> -> Compiletest 1 <host>
         [test] compiletest-ui 2 <host>
         [build] rustc 2 <host> -> rustc 3 <host>
+        [build] rustc 2 <host> -> CompiletestLintDriver 3 <host>
         [test] compiletest-ui-fulldeps 2 <host>
         [build] rustc 0 <host> -> RunMakeSupport 1 <host>
         [build] rustdoc 2 <host>
@@ -2224,7 +2227,7 @@ mod snapshot {
                 .targets(&[TEST_TRIPLE_1])
                 .args(&["ui", "ui-fulldeps", "run-make", "rustdoc", "rustdoc-gui", "incremental"])
                 .stage(2)
-                .render_steps(), @r"
+                .render_steps(), @"
         [build] llvm <host>
         [build] rustc 0 <host> -> rustc 1 <host>
         [build] rustc 1 <host> -> std 1 <host>
@@ -2236,6 +2239,8 @@ mod snapshot {
         [test] compiletest-ui 2 <target1>
         [build] llvm <target1>
         [build] rustc 2 <host> -> rustc 3 <target1>
+        [build] rustc 2 <host> -> rustc 3 <host>
+        [build] rustc 2 <host> -> CompiletestLintDriver 3 <host>
         [test] compiletest-ui-fulldeps 2 <target1>
         [build] rustc 0 <host> -> RunMakeSupport 1 <host>
         [build] rustdoc 2 <host>
@@ -2279,6 +2284,7 @@ mod snapshot {
         [test] compiletest-incremental 2 <host>
         [test] compiletest-debuginfo 2 <host>
         [build] rustc 2 <host> -> rustc 3 <host>
+        [build] rustc 2 <host> -> CompiletestLintDriver 3 <host>
         [test] compiletest-ui-fulldeps 2 <host>
         [build] rustdoc 2 <host>
         [test] compiletest-rustdoc-html 2 <host>

src/doc/rustc-dev-guide/src/tests/compiletest.md

@@ -741,6 +741,64 @@ pub fn identity(ts: TokenStream) -> TokenStream {
 > the `aux-build` header, and use `#![crate_type="proc_macro"]`, and `//@
 > force-host` and `//@ no-prefer-dynamic` headers in the proc-macro.
 
+### Auxiliary lint
+
+By using an `aux-lint` directive in a `ui-fulldeps` test, you can build a 'lint library' file which will be loaded into rustc's lints when running your test.
+
+```rs
+// tests/ui-fulldeps/lint_test.rs
+
+//@ aux-lint: my_lint.rs
+
+fn main() {
+  trigger_lint(); //~ ERROR this triggered the lint
+}
+```
+
+```rs
+// tests/ui-fulldeps/auxiliary/my_lint.rs
+
+#![feature(rustc_private)]
+
+extern crate rustc_driver;
+extern crate rustc_errors;
+extern crate rustc_hir;
+extern crate rustc_lint;
+extern crate rustc_macros;
+extern crate rustc_session;
+
+use rustc_lint::{LateContext, LateLintPass, LintContext};
+use rustc_macros::Diagnostic;
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+
+declare_tool_lint! {
+    pub example::EXAMPLE_LINT,
+    Deny,
+    "some example lint"
+}
+declare_lint_pass!(ExampleLint => [EXAMPLE_LINT]);
+
+#[derive(Diagnostic)]
+#[diag("this triggered the lint")]
+pub(crate) struct Example;
+
+impl LateLintPass<'_> for ExampleLint {
+    // lint implementation
+}
+
+#[unsafe(no_mangle)]
+unsafe extern "C" fn register_lints(
+    sess: &rustc_session::Session,
+    lint_store: &mut rustc_lint::LintStore,
+) {
+    lint_store.register_lints(&[HELLO_LINT]);
+    lint_store.register_late_pass(|_| Box::new(HelloLint));
+}
+```
+
+> **Note**: The `register_lints` signature must match _exactly_,
+> as it will be dynamically loaded by the test runner.
+
 ## Revisions
 
 Revisions allow a single test file to be used for multiple tests.

src/tools/compiletest-lint-driver/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "compiletest-lint-driver"
+version = "0.1.0"
+edition = "2024"
+
+[package.metadata.rust-analyzer]
+rustc_private = true
+
+[dependencies]
+libloading = "0.9.0"