Follow the cxx build for output file names

[ahayzen-kdab]

At the moment we use the file stem or the module ident or the cxx_file_stem depending on the situation in cxx-qt-build.

With CXX if the bridge is in src/folder/binding.rs they generate src/folder/binding.rs.h.

In this situation should we do the following

bridge type	proposed path	current path
#[cxx::bridge]	src/folder/binding.rs.h	binding.cxx.h
#[cxx_qt::bridge]	src/folder/binding.rs.qt.h	binding.cxxqt.h
#[cxx_qt::bridge(cxx_file_stem = "binding"]	binding.rs.qt.h	binding.cxxqt.h

Note that due missing support in macros we cannot find the path in the second case (as seen in #200 ) so ...

• For now disable having a cxx_qt::bridge without a cxx_file_stem until span source_file() API is stable

[LeonMatthesKDAB]

New idea:
CXX probably only needs the include! in the build script expansion, where it generates the C++ code.
So could we just emit the include! to our generated header in the build script, where we know all the paths?

If that doesn't work, we could also try hashing the tokenstream to get a unique filename that we could reference when expanding the macro.
The build script could then generate symlinks from the hashed file name to the actual path, as the build script knows the paths.

[dphaldes]

now that cxx_file_stem is gone, how do you use prevent the linking error because of same module name ?

[ahayzen-kdab]

What is the linker error you get ? As now we are following the path similar to CXX, i also wonder what happens if you do the same with CXX ?

[dphaldes]

It's a linker error. it cannot find the objects for linking the library. I have cxx-qt based Library which builds fine but when I consume it another project, it fails with linker error.

[ahayzen-kdab]

Don't know how much this is possibly related to #1065 which we hope to sort out in the next cycle.

Do you have an example project and the errors or an easy way to reproduce ?

[dphaldes]

I do. I will send it along with proper logs after I am done with work.

[dphaldes]

I did a clean update+build and it seems to start working automatically. so for now it seems to be resolved. Thanks for help!