Auto merge of rust-lang#135937 - bjorn3:separate_coretests_crate, r=jieyouxu,tgross35

Put the core unit tests in a separate coretests package

Having standard library tests in the same package as a standard library crate has bad side effects. It causes the test to have a dependency on a locally built standard library crate, while also indirectly depending on it through libtest. Currently this works out fine in the context of rust's build system as both copies are identical, but for example in cg_clif's tests I've found it basically impossible to compile both copies with the exact same compiler flags and thus the two copies would cause lang item conflicts.

This PR moves the tests of libcore to a separate package which doesn't depend on libcore, thus preventing the duplicate crates even when compiler flags don't exactly match between building the sysroot (for libtest) and building the test itself. The rest of the standard library crates do still have this issue however.

Author: bors

compiler/rustc_codegen_cranelift/build_system/tests.rs

@@ -151,7 +151,7 @@ const EXTENDED_SYSROOT_SUITE: &[TestCase] = &[
         apply_patches(
             &runner.dirs,
             "coretests",
-            &runner.stdlib_source.join("library/core/tests"),
+            &runner.stdlib_source.join("library/coretests"),
             &LIBCORE_TESTS_SRC.to_path(&runner.dirs),
         );
 

compiler/rustc_codegen_cranelift/patches/0022-coretests-Disable-not-compiling-tests.patch

@@ -10,21 +10,20 @@ Cranelift doesn't support them yet
  library/core/tests/atomic.rs          |  4 ---
  4 files changed, 4 insertions(+), 50 deletions(-)
 
-diff --git a/lib.rs b/lib.rs
+diff --git a/tests/lib.rs b/tests/lib.rs
 index 1e336bf..35e6f54 100644
---- a/lib.rs
-+++ b/lib.rs
-@@ -2,6 +2,5 @@
- #![cfg(test)]
+--- a/tests/lib.rs
++++ b/tests/lib.rs
+@@ -2,5 +2,4 @@
  // tidy-alphabetical-start
 -#![cfg_attr(target_has_atomic = "128", feature(integer_atomics))]
  #![cfg_attr(test, feature(cfg_match))]
  #![feature(alloc_layout_extra)]
  #![feature(array_chunks)]
-diff --git a/atomic.rs b/atomic.rs
+diff --git a/tests/atomic.rs b/tests/atomic.rs
 index b735957..ea728b6 100644
---- a/atomic.rs
-+++ b/atomic.rs
+--- a/tests/atomic.rs
++++ b/tests/atomic.rs
 @@ -185,10 +185,6 @@ fn atomic_alignment() {
      assert_eq!(align_of::<AtomicU64>(), size_of::<AtomicU64>());
      #[cfg(target_has_atomic = "64")]

compiler/rustc_codegen_cranelift/patches/0027-coretests-128bit-atomic-operations.patch

@@ -7,10 +7,10 @@ Subject: [PATCH] Disable long running tests
  library/core/tests/slice.rs | 2 ++
  1 file changed, 2 insertions(+)
 
-diff --git a/slice.rs b/slice.rs
+diff --git a/tests/slice.rs b/tests/slice.rs
 index 8402833..84592e0 100644
---- a/slice.rs
-+++ b/slice.rs
+--- a/tests/slice.rs
++++ b/tests/slice.rs
 @@ -1809,6 +1809,7 @@ fn sort_unstable() {
      }
  }

compiler/rustc_codegen_cranelift/patches/0028-coretests-Disable-long-running-tests.patch

@@ -72,6 +72,10 @@ dependencies = [
 [[package]]
 name = "core"
 version = "0.0.0"
+
+[[package]]
+name = "coretests"
+version = "0.0.0"
 dependencies = [
  "rand",
  "rand_xorshift",

library/Cargo.lock

@@ -3,6 +3,7 @@ resolver = "1"
 members = [
   "std",
   "sysroot",
+  "coretests",
 ]
 
 exclude = [

library/Cargo.toml

@@ -15,19 +15,6 @@ edition = "2021"
 test = false
 bench = false
 
-[[test]]
-name = "coretests"
-path = "tests/lib.rs"
-
-[[bench]]
-name = "corebenches"
-path = "benches/lib.rs"
-test = true
-
-[dev-dependencies]
-rand = { version = "0.8.5", default-features = false }
-rand_xorshift = { version = "0.3.0", default-features = false }
-
 [features]
 # Make panics and failed asserts immediately abort without formatting any message
 panic_immediate_abort = []

library/core/Cargo.toml

@@ -44,7 +44,7 @@
 //!    called. The `lang` attribute is called `eh_personality`.
 
 // Since core defines many fundamental lang items, all tests live in a
-// separate crate, libcoretest (library/core/tests), to avoid bizarre issues.
+// separate crate, coretests (library/coretests), to avoid bizarre issues.
 //
 // Here we explicitly #[cfg]-out this whole crate when testing. If we don't do
 // this, both the generated test artifact and the linked libtest (which

library/core/src/lib.rs

@@ -0,0 +1,27 @@
+[package]
+name = "coretests"
+version = "0.0.0"
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/rust-lang/rust.git"
+description = "Tests for the Rust Core Library"
+autotests = false
+autobenches = false
+edition = "2021"
+
+[lib]
+path = "lib.rs"
+test = false
+bench = false
+
+[[test]]
+name = "coretests"
+path = "tests/lib.rs"
+
+[[bench]]
+name = "corebenches"
+path = "benches/lib.rs"
+test = true
+
+[dev-dependencies]
+rand = { version = "0.8.5", default-features = false }
+rand_xorshift = { version = "0.3.0", default-features = false }