cargo test gives linker errors

[jgilchrist]

For example:

---- engine::actor::Actor_0 stdout ----
    error: linking with `cc` failed: exit code: 1
note: cc '-Wl,--as-needed' '-m64' '-L' '/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib' '-o' '/tmp/rustdoctest.r1BGY18VAAb0/rust-out' '/tmp/rustdoctest.r1BGY18VAAb0/rust_out.o' '-Wl,--whole-archive' '-lmorestack' '-Wl,--no-whole-archive' '-Wl,--gc-sections' '-pie' '-nodefaultlibs' '/home/jonny/code/rslike/target/librslike-33665a348a9c0d5a.rlib' '/home/jonny/code/rslike/target/deps/libtcod-835af025147faddf.rlib' '/home/jonny/code/rslike/target/deps/libtcod-sys-8caba187ba4adc8b.rlib' '-L' '/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib' '-lstd-4e7c5e5c' '-L' '/home/jonny/code/rslike/target' '-L' '/home/jonny/code/rslike/target/deps' '-L' '/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib' '-L' '/home/jonny/code/rslike/.rust/lib/x86_64-unknown-linux-gnu' '-L' '/home/jonny/code/rslike/lib/x86_64-unknown-linux-gnu' '-Wl,--whole-archive' '-Wl,-Bstatic' '-Wl,--no-whole-archive' '-Wl,-Bdynamic' '-ltcod' '-ltcod' '-ltcod' '-ldl' '-lpthread' '-lrt' '-lgcc_s' '-lpthread' '-lc' '-lm' '-lcompiler-rt'
note: /usr/bin/ld: cannot find -ltcod
/usr/bin/ld: cannot find -ltcod
/usr/bin/ld: cannot find -ltcod
collect2: error: ld returned 1 exit status

error: aborting due to previous error
thread 'engine::actor::Actor_0' panicked at 'Box<Any>', /home/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libsyntax/diagnostic.rs:144

For some reason, it's passing the flag -ltcod to the linker three times. This doesn't happen when building, only when testing.

[tomassedovic]

Hm, strange. I've just updated to latest Rust and I can't reproduce the issue.

Running cargo test within tcod-rs works as expected. Looking at the error it seems you're seeing it within another app, right? I tried cargo new with tcod as a dependency and copied one of the examples. Again cargo test just works.

What's your rustc --version --verbose? For comparison, mine is:

$ rustc --version --verbose
rustc 1.0.0-nightly (8903c21d6 2015-01-15 22:42:58 +0000)
binary: rustc
commit-hash: 8903c21d618fd25dca61d9bb668c5299d21feac9
commit-date: 2015-01-15 22:42:58 +0000
host: x86_64-unknown-linux-gnu
release: 1.0.0-nightly

I checked Rust's issues and recent commits. Found a few things that seem related but I can't really tell:

rust-lang/rust#21089

then this, which seems like it's doing something with linking. So this might be a fix or a regression (or completely unrelated):
rust-lang/rust@cbeb77e

Other than that, I dunno. Can you try updating to latest Rust master and reproducing? If that fails, it's probably a bug in Rust (third-party code should never crash the compile like this). Any chance you could try get a small reproducible example (ideally a single file + Cargo.toml) and link it here?

I'll try to reproduce & debug it and we can file an issue with Rust.

Oh, also: whenever Rust crashes, try to re-run it with RUST_BACKTRACE=1 environment variable set. That should print out a proper backtrace.

And one more thing: I've had a few rust crashes that looked similar with the debugging symbols enabled. Try setting debug = false in the dev and test profiles in your Cargo.toml. Like here:

https://github.com/tomassedovic/tcod-rs/blob/master/Cargo.toml#L27

It's a long shot, but it worked around the crash for me a few times already.

[jgilchrist]

Yeah, I saw this in travis-ci when I pushed a branch on my roguelike.

$ rustc --version --verbose
rustc 1.0.0-nightly (8903c21d6 2015-01-15 22:42:58 +0000)
binary: rustc
commit-hash: 8903c21d618fd25dca61d9bb668c5299d21feac9
commit-date: 2015-01-15 22:42:58 +0000
host: x86_64-unknown-linux-gnu
release: 1.0.0-nightly

I couldn't reproduce it locally either, cargo test ran fine, but then I realised that I have a version of libtcod installed locally, so -ltcod works even though it shouldn't. Uninstalling the system libtcod means I can reproduce the errors on my machine. Turning off debugging symbols didn't do anything.

[jgilchrist]

The full error for a single failing test:

---- engine::actor::new_0 stdout ----
    error: linking with `cc` failed: exit code: 1
note: cc '-Wl,--as-needed' '-m64' '-L' '/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib' '-o' '/tmp/rustdoctest.sFzeE1E4an78/rust-out' '/tmp/rustdoctest.sFzeE1E4an78/rust_out.o' '-Wl,--whole-archive' '-lmorestack' '-Wl,--no-whole-archive' '-Wl,--gc-sections' '-pie' '-nodefaultlibs' '/home/jonny/code/rslike/target/librslike-33665a348a9c0d5a.rlib' '/home/jonny/code/rslike/target/deps/libtcod-835af025147faddf.rlib' '/home/jonny/code/rslike/target/deps/libtcod-sys-8caba187ba4adc8b.rlib' '-L' '/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib' '-lstd-4e7c5e5c' '-L' '/home/jonny/code/rslike/target' '-L' '/home/jonny/code/rslike/target/deps' '-L' '/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib' '-L' '/home/jonny/code/rslike/.rust/lib/x86_64-unknown-linux-gnu' '-L' '/home/jonny/code/rslike/lib/x86_64-unknown-linux-gnu' '-Wl,--whole-archive' '-Wl,-Bstatic' '-Wl,--no-whole-archive' '-Wl,-Bdynamic' '-ltcod' '-ltcod' '-ltcod' '-ldl' '-lpthread' '-lrt' '-lgcc_s' '-lpthread' '-lc' '-lm' '-lcompiler-rt'
note: /usr/bin/ld: cannot find -ltcod
/usr/bin/ld: cannot find -ltcod
/usr/bin/ld: cannot find -ltcod
collect2: error: ld returned 1 exit status

error: aborting due to previous error
thread 'engine::actor::new_0' panicked at 'Box<Any>', /home/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libsyntax/diagnostic.rs:144

stack backtrace:
   1:     0x7f0d8802c000 - sys::backtrace::write::h7e8ba1fc274cc36epRt
   2:     0x7f0d8804d9e0 - failure::on_fail::h823798930ebe140a64z
   3:     0x7f0d87fbc7b0 - rt::unwind::begin_unwind_inner::ha4a8df6010104da6ZJz
   4:     0x7f0d83046cd0 - rt::unwind::begin_unwind::h15231093072926810949
   5:     0x7f0d830474c0 - diagnostic::Handler::fatal::hf2fba868154a7d81Q0F
   6:     0x7f0d83047730 - diagnostic::Handler::abort_if_errors::h49ed039430cd670by2F
   7:     0x7f0d871282d0 - back::link::link_natively::hf78742a8a3f2054bCXa
   8:     0x7f0d87120820 - back::link::link_binary::hd00660e13e96680bSua
   9:     0x7f0d87611270 - driver::phase_6_link_output::hcf0e359de93d6713rPa
  10:     0x7f0d875efd70 - driver::compile_input::h8ec974b2bd4afe59Aba
  11:     0x7f0d8866c530 - test::runtest::h51d251a4024cad3bj2t
  12:     0x7f0d88677320 - thunk::F.Invoke<A, R>::invoke::h1954005010071349229
  13:     0x7f0d87930050 - thunk::F.Invoke<A, R>::invoke::h12312287147979335838
  14:     0x7f0d87926a50 - thunk::F.Invoke<A, R>::invoke::h10273972757065453811
  15:     0x7f0d87927200 - rt::unwind::try::try_fn::h6611577649401309552
  16:     0x7f0d880b4b90 - rust_try_inner
  17:     0x7f0d880b4b80 - rust_try
  18:     0x7f0d879274b0 - thunk::F.Invoke<A, R>::invoke::h12348411253666505759
  19:     0x7f0d8803b680 - sys::thread::thread_start::h2ac456e96ea03cedcJw
  20:     0x7f0d82862250 - start_thread
  21:     0x7f0d87c6d219 - clone
  22:                0x0 - <unknown>

[jgilchrist]

rust-lang/rust#21246 looks like the issue. Potentially a bug in Cargo.

[tomassedovic]

Ugh :-/

In case you missed, I've noticed this workaround they did in Servo:

https://github.com/servo/servo/pull/4643/files

[jgilchrist]

I saw, but we can't really ask people who use this library to disable their doctests. There's been no activity on the issue in Rust, so I'm not really sure the deal is.

[tomassedovic]

Yeah, good point.

[jgilchrist]

The problem seems to be that the tcod-sys output directory is not passed to rustdoc:

The call to rustc:

rustc src/lib.rs --crate-name rslike --crate-type lib -g -C metadata=33665a348a9c0d5a -C extra-filename=-33665a348a9c0d5a --out-dir /home/jonny/code/rslike/target --emit=dep-info,link 
-L dependency=/home/jonny/code/rslike/target 
-L dependency=/home/jonny/code/rslike/target/deps 
--extern tcod=/home/jonny/code/rslike/target/deps/libtcod-ced67c17ab23ef28.rlib 
-L /home/jonny/code/rslike/target/build/tcod-sys-f8f3021d7cdb0f8e/out

The call to rustdoc:

rustdoc --test /home/jonny/code/rslike/src/lib.rs --crate-name rslike 
-L /home/jonny/code/rslike/target -L /home/jonny/code/rslike/target/deps 
--extern bitflags=/home/jonny/code/rslike/target/deps/libbitflags-518ea12e21428edd.rlib 
--extern tcod-sys=/home/jonny/code/rslike/target/deps/libtcod-sys-f8f3021d7cdb0f8e.rlib 
--extern tcod=/home/jonny/code/rslike/target/deps/libtcod-ced67c17ab23ef28.rlib 
--extern rslike=/home/jonny/code/rslike/target/librslike-33665a348a9c0d5a.rlib

Specifically, this line in the first:

-L /home/jonny/code/rslike/target/build/tcod-sys-f8f3021d7cdb0f8e/out

[jgilchrist]

Fixed with rust-lang/cargo#1530