'cargo test' does not compile when pymethods is used

[pchampin]

🐛 Bug Reports

When I use #[pymethods] in my project, cargo test no longer compiles.

🌍 Environment

• Your operating system and version:
  → Linux Ubuntu 19.10
• Your python version:
  → Python 3.7.5 (default, Nov 20 2019, 09:21:52)
  [GCC 9.2.1 20191008] on linux
• How did you install python (e.g. apt or pyenv)? Did you use a virtualenv?
  → I installed python3 with apt, and use it from a venv
• Your rust version (rustc --version):
  → rustc 1.42.0 (b8cedc004 2020-03-09)
• Are you using the latest pyo3 version? Have you tried using latest master (replace version = "0.x.y" with git = "https://github.com/PyO3/pyo3")?
  → I tried both

💥 Reproducing

I started with the simple example given here, and added a test module. cargo +nightly test runs fine.
I then added

#[pyclass]
pub struct Foo {}

#[pymethods]
impl Foo {}

and cargo +nightly test still runs fine.

But as soon as I add a function even doing nothing (pub fn foo() {}) in the impl block, cargo +nightly test gives me the compilation error below. Note that cargo +nightly build still works fine.

Compilation error:

error: linking with `cc` failed: exit code: 1
  |
  = note: "cc" "-Wl,--as-needed" "-Wl,-z,noexecstack" "-m64" "-L" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.109hleyh2kp0fsyr.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.10dkyc5kd9ymq73s.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.17quxwlbrqw8hj7s.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.1l1b084h09aptdzo.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.1lkhs9iu8wspfkhf.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.1tcmqx3sh5gyqj6t.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.1u6vlfjgt6wio4lf.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.1wfkrdcmhd0whgdg.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.1zv6gwij13dpfn7z.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.2001hl8uuc4y81bo.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.236617qglm5yim3e.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.2678j2qn322y5300.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.28n31dnuutnz8nvi.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.2952miup9uwgv41l.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.29wcml04ji4c5bbr.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.2c1scr6irhr136e9.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.2gb5mkukcl7wgu4y.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.2ma0nsfwxja118p0.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.2w014i84gnlsprgs.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.2x5w2tzty48bxje3.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.2yd1o35s5xap7vab.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.31boqiy4lltzvs9n.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.34t2sm4va5o8rk.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.366raiq0lz40zp.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.3asnyr45w8pichcv.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.3befyxmor2kkdft2.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.3j29qwiii5c8sip1.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.3ki8y7i2r6i4an6f.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.3thhymiru7psgb3y.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.3v1ls757czydoeju.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.3v2yvtz7befxts8v.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.3ynedg6e3b3v732d.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.411cgqrcxt42r1mk.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.43s7tvv0w42w4oun.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.45pn5owcijeiri51.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.494f42qd5punoiez.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.4g4yebi4qwfkec58.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.4lv2rq299mlu7pne.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.4wrwi7gyfp9r1xm.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.4zn2ep2tlkijbz0e.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.52hm7meb4t4rbi0e.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.55go9xoi3bec2pa3.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.55yxgqbp2yk0vcsj.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.58di4ncs82owc9sw.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.59esv7vihzc7lh53.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.5c2n2zl3040u3pod.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.5ce9b6o05cwica41.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.5cw9wv05c0el02f0.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.5eahuwbut371kzph.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.8q7czd6l8m9lblx.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.h7rc8s4f3pmt8lm.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.ljyeefxcnm5fgdw.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.pgj76pv82n7h4dd.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.wc1d6gatqnk4xxx.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.xy38jrqqijayk8z.rcgu.o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.z80n0bfar9kbqxg.rcgu.o" "-o" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0" "/home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.16944yh97yo1rkmx.rcgu.o" "-Wl,--gc-sections" "-pie" "-Wl,-zrelro" "-Wl,-znow" "-nodefaultlibs" "-L" "/home/pa/tmp/test_pyo3/target/debug/deps" "-L" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-Wl,-Bstatic" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libtest-8a232aaa4454fc17.rlib" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libterm-9635ba058a6160dc.rlib" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libgetopts-931b34d451d8130e.rlib" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libunicode_width-29248e68b923678e.rlib" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_std_workspace_std-376d95deefd17798.rlib" "/home/pa/tmp/test_pyo3/target/debug/deps/libpyo3-3d7cd1cf4d05e29b.rlib" "/home/pa/tmp/test_pyo3/target/debug/deps/libparking_lot-2bf5336fc56f76af.rlib" "/home/pa/tmp/test_pyo3/target/debug/deps/libparking_lot_core-c3a7647ed7ed5765.rlib" "/home/pa/tmp/test_pyo3/target/debug/deps/libcfg_if-1c7f54a97c5ff6c5.rlib" "/home/pa/tmp/test_pyo3/target/debug/deps/libsmallvec-d167b13726385e4a.rlib" "/home/pa/tmp/test_pyo3/target/debug/deps/liblock_api-d702a9963fb46fca.rlib" "/home/pa/tmp/test_pyo3/target/debug/deps/libscopeguard-53e4b3a35014edc9.rlib" "/home/pa/tmp/test_pyo3/target/debug/deps/libnum_traits-b79287dec04ed2f9.rlib" "/home/pa/tmp/test_pyo3/target/debug/deps/libunindent-5ce5fd00d38e4c89.rlib" "/home/pa/tmp/test_pyo3/target/debug/deps/liblibc-21dfdb5f02666556.rlib" "/home/pa/tmp/test_pyo3/target/debug/deps/libinventory-9b772211fa0028ee.rlib" "/home/pa/tmp/test_pyo3/target/debug/deps/libindoc-8270e20bc513f675.rlib" "/home/pa/tmp/test_pyo3/target/debug/deps/libpaste-8f554db8ac103451.rlib" "-Wl,--start-group" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd-08d9f9dbf3ce8ba6.rlib" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libpanic_unwind-c8bbb97721eece57.rlib" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libhashbrown-f915ad27f26cc43a.rlib" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_std_workspace_alloc-ba963b08c33add93.rlib" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libbacktrace-073a5442c7e05cbd.rlib" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libbacktrace_sys-9a15745a8e512430.rlib" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_demangle-5ebca2692bc4c1c4.rlib" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libunwind-1411abf081cbe734.rlib" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcfg_if-79269dab5354ed4f.rlib" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/liblibc-a27c87eea3474d78.rlib" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/liballoc-f42bfa01fbd99718.rlib" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_std_workspace_core-882aa800a25c0b7c.rlib" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcore-a2ab15a95dc279ee.rlib" "-Wl,--end-group" "/home/pa/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcompiler_builtins-b12142e6382b96eb.rlib" "-Wl,-Bdynamic" "-lutil" "-ldl" "-lutil" "-ldl" "-lrt" "-lpthread" "-lgcc_s" "-lc" "-lm" "-lrt" "-lpthread" "-lutil" "-lutil"
  = note: /usr/bin/ld: /home/pa/tmp/test_pyo3/target/debug/deps/test_pyo3-41ae250cadef73a0.2678j2qn322y5300.rcgu.o: in function `pyo3::err::PyErr::restore':
          /home/pa/.cargo/git/checkouts/pyo3-a22e69bc62b9f0fd/1aa4ae8/src/err.rs:345: undefined reference to `PyErr_Restore'
          /usr/bin/ld: /home/pa/tmp/test_pyo3/target/debug/deps/libpyo3-3d7cd1cf4d05e29b.rlib(pyo3-3d7cd1cf4d05e29b.pyo3.1adzdfmu-cgu.0.rcgu.o): in function `pyo3::err::PyErr::new_type':
          /home/pa/.cargo/git/checkouts/pyo3-a22e69bc62b9f0fd/1aa4ae8/src/err.rs:209: undefined reference to `PyErr_NewException'
          /usr/bin/ld: /home/pa/tmp/test_pyo3/target/debug/deps/libpyo3-3d7cd1cf4d05e29b.rlib(pyo3-3d7cd1cf4d05e29b.pyo3.1adzdfmu-cgu.0.rcgu.o): in function `pyo3::err::panic_after_error':
          /home/pa/.cargo/git/checkouts/pyo3-a22e69bc62b9f0fd/1aa4ae8/src/err.rs:552: undefined reference to `PyErr_Print'
          /usr/bin/ld: /home/pa/tmp/test_pyo3/target/debug/deps/libpyo3-3d7cd1cf4d05e29b.rlib(pyo3-3d7cd1cf4d05e29b.pyo3.1adzdfmu-cgu.1.rcgu.o): in function `pyo3::gil::prepare_freethreaded_python::{{closure}}':
          /home/pa/.cargo/git/checkouts/pyo3-a22e69bc62b9f0fd/1aa4ae8/src/gil.rs:39: undefined reference to `Py_IsInitialized'
          /usr/bin/ld: /home/pa/.cargo/git/checkouts/pyo3-a22e69bc62b9f0fd/1aa4ae8/src/gil.rs:57: undefined reference to `Py_InitializeEx'
          /usr/bin/ld: /home/pa/.cargo/git/checkouts/pyo3-a22e69bc62b9f0fd/1aa4ae8/src/gil.rs:68: undefined reference to `PyEval_SaveThread'
          /usr/bin/ld: /home/pa/tmp/test_pyo3/target/debug/deps/libpyo3-3d7cd1cf4d05e29b.rlib(pyo3-3d7cd1cf4d05e29b.pyo3.1adzdfmu-cgu.1.rcgu.o): in function `<pyo3::gil::GILGuard as core::ops::drop::Drop>::drop':
          /home/pa/.cargo/git/checkouts/pyo3-a22e69bc62b9f0fd/1aa4ae8/src/gil.rs:111: undefined reference to `PyGILState_Release'
          /usr/bin/ld: /home/pa/tmp/test_pyo3/target/debug/deps/libpyo3-3d7cd1cf4d05e29b.rlib(pyo3-3d7cd1cf4d05e29b.pyo3.1adzdfmu-cgu.1.rcgu.o): in function `pyo3::gil::GILGuard::acquire':
          /home/pa/.cargo/git/checkouts/pyo3-a22e69bc62b9f0fd/1aa4ae8/src/gil.rs:235: undefined reference to `PyGILState_Ensure'
          /usr/bin/ld: /home/pa/tmp/test_pyo3/target/debug/deps/libpyo3-3d7cd1cf4d05e29b.rlib(pyo3-3d7cd1cf4d05e29b.pyo3.1adzdfmu-cgu.13.rcgu.o): in function `pyo3::ffi::object::Py_DECREF':
          /home/pa/.cargo/git/checkouts/pyo3-a22e69bc62b9f0fd/1aa4ae8/src/ffi/object.rs:931: undefined reference to `_Py_Dealloc'
          /usr/bin/ld: /home/pa/tmp/test_pyo3/target/debug/deps/libpyo3-3d7cd1cf4d05e29b.rlib(pyo3-3d7cd1cf4d05e29b.pyo3.1adzdfmu-cgu.13.rcgu.o): in function `pyo3::ffi::object::Py_None':
          /home/pa/.cargo/git/checkouts/pyo3-a22e69bc62b9f0fd/1aa4ae8/src/ffi/object.rs:973: undefined reference to `_Py_NoneStruct'
          /usr/bin/ld: /home/pa/tmp/test_pyo3/target/debug/deps/libpyo3-3d7cd1cf4d05e29b.rlib(pyo3-3d7cd1cf4d05e29b.pyo3.1adzdfmu-cgu.15.rcgu.o): in function `<pyo3::exceptions::RuntimeError as pyo3::type_object::PyTypeObject>::type_object':
          /home/pa/.cargo/git/checkouts/pyo3-a22e69bc62b9f0fd/1aa4ae8/src/exceptions.rs:218: undefined reference to `PyExc_RuntimeError'
          collect2: error: ld returned 1 exit status

[kngwyu]

See https://github.com/PyO3/pyo3/releases/tag/v0.6.0 for the workaround.