Reusing artifacts in target from previous (CMake non-related) build

[mladedav]

I am building my crate in CI and if that succeeds I build it again with CMake. I think there should be a way to skip this additional compilation by reusing the artifacts in the target directory.

This can probably be solved fairly easily once --out-dir is stabilized (context; this may not be stabilized ever) by allowing the user to specify a preexisting target directory while keeping just the output local to cmake.

But until then I'm not so sure. I know simply moving the target directory anywhere wouldn't work since there are absolute paths there based on which recompilation is triggered. I tried to test it and it triggered the compilation but honestly I'm still a bit confused sometimes when cargo decides to rebuild.

[jschwe]

Have you considered using "sccache" to cache your compilation results?

[Be-ing]

We are using sccache on CXX-Qt's CI to cache both C++ and Rust and it works well.

[jschwe]

Closing in favor of issue #328, which would also address this issue.