tests: port jobserver-error.rs to rmake.rs

Co-authored-by: Noa <[email protected]>
Co-authored-by: Oneirical <[email protected]>

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -1,6 +1,5 @@
 run-make/cat-and-grep-sanity-check/Makefile
 run-make/extern-fn-reachable/Makefile
-run-make/jobserver-error/Makefile
 run-make/split-debuginfo/Makefile
 run-make/symbol-mangling-hashed/Makefile
 run-make/translation/Makefile

tests/run-make/jobserver-error/rmake.rs

@@ -0,0 +1,55 @@
+//! If the environment variables contain an invalid `jobserver-auth`, this used to cause an ICE
+//! until this was fixed in [do not panic on failure to acquire jobserver token
+//! #109694](https://github.com/rust-lang/rust/pull/109694).
+//!
+//! Proper handling has been added, and this test checks that helpful warnings and errors are
+//! printed instead in case of a wrong jobserver. See
+//! <https://github.com/rust-lang/rust/issues/46981>.
+
+//@ only-linux
+//@ ignore-cross-compile
+
+use run_make_support::{diff, rustc};
+
+fn main() {
+    let out = rustc()
+        .stdin_buf(("fn main() {}").as_bytes())
+        .env("MAKEFLAGS", "--jobserver-auth=5,5")
+        .run_fail()
+        .stderr_utf8();
+    diff().expected_file("cannot_open_fd.stderr").actual_text("actual", out).run();
+
+    // SAFETY(io-safety): we don't have overlapping fd 3.
+    let out = unsafe {
+        rustc()
+            .stdin_buf(("fn main() {}").as_bytes())
+            .input("-")
+            .env("MAKEFLAGS", "--jobserver-auth=3,3")
+            .set_aux_fd(3, std::fs::File::open("/dev/null").unwrap())
+            .run()
+            .stderr_utf8()
+    };
+    diff().expected_file("not_a_pipe.stderr").actual_text("actual", out).run();
+
+    // FIXME(#110321): this case is spurious because:
+    //
+    // > the jobserver helper thread launched here gets starved out and doesn't run, while the
+    // > coordinator thread continually processes work using the implicit jobserver token, never
+    // > yielding long enough for the jobserver helper to do its work (and process the error).
+    //
+    // but is not necessarily worth fixing as it might require changing coordinator behavior that
+    // might regress performance. See discussion at
+    // <https://github.com/rust-lang/rust/issues/110321#issuecomment-1636914956>.
+
+    //let (readpipe, _) = std::pipe::pipe().unwrap();
+    //let out = unsafe {
+    //    rustc()
+    //        .stdin("fn main() {}")
+    //        .input("-")
+    //        .env("MAKEFLAGS", "--jobserver-auth=3,3")
+    //        .set_aux_fd(3, readpipe)
+    //        .run()
+    //        .stderr_utf8()
+    //};
+    //diff().expected_file("poisoned_pipe.stderr").actual_text("actual", out).run();
+}