Improve hydro_deploy build error reporting, fix stageleft windows paths

[MingweiSamuel]

No description provided.

[shadaj]

These test failures are strange, it seems that the cfg(target_os = ...) is behaving differently when cargo is invoked by Hydro Deploy. Hydro Deploy shouldn't be specifying any target though, we leave it as the default for a Localhost host, so I'm a bit confused why this is happening.

[MingweiSamuel]

@shadaj I also can't repro (anymore) on my local windows, lol. Removing the CI for now and testing more

[shadaj]

I wonder if we need to be using which to grab the right cargo from the PATH, I vaguely remember needing to do something similar when invoking processes in another project.

[MingweiSamuel]

Actually can reproduce again locally. Build seems to be broken in typenum paholg/typenum#195

Will merge this and continue

[MingweiSamuel]

Seems like OUT_DIR is getting mutilated:
D:\Projects\hydroflow\target\debug\build\typenum-27ab1f3e5e6288a0\out normally
vs
\\?\D:\Projects\hydroflow\target\release\build\typenum-123f6570ec25fa24\out when the error occurs

[MingweiSamuel]

paholg/typenum#195 (comment)

include!(r"D:\Projects\typenum_test/include.rs"); // works
include!(r"\\?\D:\Projects\typenum_test\include.rs"); // works
include!(r"\\?\D:\Projects\typenum_test/include.rs"); // ERROR

[MingweiSamuel]

https://github.com/rust-lang/cargo/blob/f9946d15dfdc7128f8156c29ef9981f13a9ad959/src/doc/contrib/src/implementation/filesystem.md?plain=1#L12
https://stackoverflow.com/questions/21194530/what-does-mean-when-prepended-to-a-file-path

[shadaj]

Yep, https://stackoverflow.com/questions/50322817/how-do-i-remove-the-prefix-from-a-canonical-windows-path. We canonicalize the src path before using it as the current dir for the command.