rust: Store absolute paths in rust-project.json

[sdroege]

As meson requires source_dir!=build_dir and stores the rust-project.json inside the build directory, while software like rust-analyzer expects it at the root of the source directory, manual steps are needed for making them work together.

One option, as described in the documentation, is per project configuration. Another option, that works correctly with compile-commands.json and clangd, is to store a symlink to the file in the build directory at the root of the source directory.

As currently rust-project.json stores paths relative to the location of the file itself and rust-analyzer does not resolve symlinks, this does not work.

To solve this, store absolute paths in rust-project.json as is already done in compile_commands.json for the directory.

---

rust-analyzer PR to resolve symlinks: rust-lang/rust-analyzer#14168

CC @dcbaker

[sdroege]

See also rust-lang/rust-analyzer#14168

[dcbaker]

the changes themselves look good to me. Thanks for looking at this, and especially taking the issue upstream :)

I (unfortunately, because I find pathlib to much nicer than os.path), also find it to have an unfortunate set of bugs and problematic behaviors that make it not actually as useful as it should be.

With the pathlib -> os.path changes this is r-b from me

[codecov]

Codecov Report

Merging #11467 (0bfd4e6) into master (b80f845) will increase coverage by 1.70%.
The diff coverage is n/a.

❗ Current head 0bfd4e6 differs from pull request most recent head fcefc36. Consider uploading reports for the commit fcefc36 to get more accurate results

@@            Coverage Diff             @@
##           master   #11467      +/-   ##
==========================================
+ Coverage   67.08%   68.79%   +1.70%     
==========================================
  Files         418      209     -209     
  Lines       90828    45480   -45348     
  Branches    20177     9415   -10762     
==========================================
- Hits        60936    31289   -29647     
+ Misses      25209    11775   -13434     
+ Partials     4683     2416    -2267     

Impacted Files	Coverage Δ
interpreterbase/interpreterbase.py	72.96% <0.00%> (-4.64%)	⬇️
msetup.py	89.21% <0.00%> (-0.84%)	⬇️
mesonbuild/backend/ninjabackend.py
mesonbuild/compilers/compilers.py
mesonbuild/compilers/d.py
mesonbuild/compilers/mixins/clike.py
mesonbuild/coredata.py
mesonbuild/dependencies/python.py
mesonbuild/interpreter/compiler.py
mesonbuild/interpreterbase/interpreterbase.py
... and 207 more

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[nirbheek]

I (unfortunately, because I find pathlib to much nicer than os.path), also find it to have an unfortunate set of bugs and problematic behaviors that make it not actually as useful as it should be.

Completely agree. I was all aboard the pathlib train till I started to actually use it, and now I'm fully off it.

[sdroege]

Updated but don't merge this yet. The problem right now is that if you run meson from inside the build directory it writes the correct path, if you run it from the source directory it won't (and will put a path relative to the source directory).

[sdroege]

I think this should be fixed directly in generate_rust_target instead.

[sdroege]

This should work fine. For the proc macro dylib path this should be unnecessary as it seems to generate an absolute path already.

[sdroege]

Also fixed the proc-macro handling there in another commit. That was completely broken but now the test cases/rust/18 proc-macro/ testcase works correctly.

[sdroege]

test cases/rust/11 generated main needs fixing

[sdroege]

Works here now but for some of the test cases rust-analyzer doesn't find dependencies (before and after my changes).