[E0464]: multiple matching crates after using cargo check

[hdhoang]

Running cargo check creates a .rmeta file with a different hash than the actual rlib built. This makes cargo test unable to compile tests which import the tested crate for integration testing.

This travis build fails because of the duplicate files https://travis-ci.org/hdhoang/testee/jobs/285433441#L481
It runs fine after removing the rmeta file https://travis-ci.org/hdhoang/testee/builds/285434745#L443

This is possibly related to rust-lang/cargo#3501. Until check and build use the same metadata, this issue would hinder compiletest-rs adoption.

I think we can workaround this by removing the relevant rmeta files when building tests.

[laumann]

That does seem annoying... Could removal of the *.rmeta be done as part of the test initialization or is that too late? If it's too late, then I'm not sure this is fixable in compiletest. A feature of Config could be to clear out *.rmeta in build folders on request.

As a side question, why use cargo check for integration testing? Is it even necessary (to run tests, you'd have to run build at some point anyway).

[hdhoang]

Thank you for your pointer, I'll try that out.

I run cargo check during normal development, but it still creates the conflicting *.rmeta discovered from tests/run-pass/*.rs. Later, cargo test gets confused by those during actual testing.

[laumann]

I run cargo check during normal development

Ah, I see. It's not the test suite that runs cargo check, sorry :-)