Can't run compiletests on Mac when DYLD_LIBRARY_PATH is unset or empty

[jorendorff]

Two separate bugs here. Full output below, but in short:

• if DYLD_LIBRARY_PATH is not set, compiletest fails in Config::link_deps: https://github.com/laumann/compiletest-rs/blob/master/src/common.rs#L253-L255
• if it's empty, or contains any empty components, compiletest adds " -L " to the target_rustcflags, without anything after it.

Part of the problem here is that std::env::split_paths("") is not an empty sequence [], but has one empty element [""] (Playground example). So a workaround is needed for that.

$ cargo test
    Finished test [unoptimized + debuginfo] target(s) in 0.03s
     Running target/debug/deps/image-2fef4cbf6d86ba78

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

     Running target/debug/deps/runtests-d1b0a6cde5f3e413

running 1 test
test compile_test ... FAILED

failures:

---- compile_test stdout ----
thread 'compile_test' panicked at 'Cannot link to dependencies. Problem with env var 'DYLD_LIBRARY_PATH': NotPresent', /Users/jorendorff/.cargo/registry/src/github.com-1ecc6299db9ec823/compiletest_rs-0.5.0/src/common.rs:254:13
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace


failures:
    compile_test

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out

error: test failed, to rerun pass '--test runtests'

$ DYLD_LIBRARY_PATH= cargo test
    Finished test [unoptimized + debuginfo] target(s) in 0.05s
     Running target/debug/deps/image-2fef4cbf6d86ba78

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

     Running target/debug/deps/runtests-d1b0a6cde5f3e413

running 1 test

running 8 tests
test [compile-fail] asynchronous/future-not-send-dyn.rs ... FAILED
test [compile-fail] asynchronous/future-lifetime.rs ... FAILED
test [compile-fail] asynchronous/async-block-return-type.rs ... FAILED
test [compile-fail] asynchronous/future-not-send-rc.rs ... FAILED
test [compile-fail] asynchronous/async-fn-not-unpin.rs ... FAILED
test [compile-fail] asynchronous/wrong_mutex.rs ... FAILED
test [compile-fail] asynchronous/fake-read-to-string.rs ... FAILED
test [compile-fail] asynchronous/left-or-right.rs ... FAILED

failures:

failures:
    [compile-fail] asynchronous/async-block-return-type.rs
    [compile-fail] asynchronous/async-fn-not-unpin.rs
    [compile-fail] asynchronous/fake-read-to-string.rs
    [compile-fail] asynchronous/future-lifetime.rs
    [compile-fail] asynchronous/future-not-send-dyn.rs
    [compile-fail] asynchronous/future-not-send-rc.rs
    [compile-fail] asynchronous/left-or-right.rs
    [compile-fail] asynchronous/wrong_mutex.rs

test result: FAILED. 0 passed; 8 failed; 0 ignored; 0 measured; 0 filtered out

test compile_test ... FAILED

failures:

---- compile_test stdout ----

error: asynchronous/future-lifetime.rs:44: expected error not found: `host` does not live long enough

error: asynchronous/async-block-return-type.rs:48: expected note not found: consider giving `future` a type

error: 
error: asynchronous/future-lifetime.rs:44: expected error not found: `path` does not live long enough
asynchronous/async-block-return-type.rs:53: expected error not found: type annotations needed

error: 0 unexpected errors found, 2 expected errors not found
status: exit code: 1
command: "rustc" "asynchronous/future-lifetime.rs" "-L" "/var/folders/2f/vxcscyq11kg3439lb05pmj8c0000gn/T/" "--target=x86_64-apple-darwin" "--error-format" "json" "-C" "prefer-dynamic" "-o" "/var/folders/2f/vxcscyq11kg3439lb05pmj8c0000gn/T/future-lifetime.stage-id" "-A" "unused" "--edition" "2018" "--extern" "image" "-L" "-L" "/var/folders/2f/vxcscyq11kg3439lb05pmj8c0000gn/T/future-lifetime.stage-id.aux"
...

Note the "-L" "-L" "/var/..." at the end of the rustc command. The first -L is added by Config::link_deps, because the environment variable is empty. If I do LD_LIBRARY_PATH=banana cargo test, tests run normally.

[Munksgaard]

Thank you for reporting this issue. I cannot promise that I, or anyone else, will fix it right away, but pull requests are most welcome 🙂