Use system nanobind if installed

[cjmayo]

I think I saw mention of supporting system nanobind in one of the discussions, it is becoming a thing now.

This uses the recommended approach - with additional version checking.

This still falls back to the third_party directory for now, but obviously that is easily replaced. For pyproject.toml users automatically fetching nanobind is supported.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.08%. Comparing base (d437097) to head (be2846e).
Report is 67 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #880      +/-   ##
==========================================
- Coverage   91.84%   90.08%   -1.77%     
==========================================
  Files          37       64      +27     
  Lines        4976     9184    +4208     
  Branches        0      956     +956     
==========================================
+ Hits         4570     8273    +3703     
- Misses        406      911     +505     

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[elalish]

I think in general that fewer submodules would be great. Any reason not to remove it from third_party? I'll defer to @pca006132 on approving this one.

[pca006132]

It seems that when building using python build, it automatically checks nanobind version and fail when it is not installed, even when we have a submodule.

Re. submodule, I think we can switch to FetchContent as well.

[pca006132]

It seems that when building using python build, it automatically checks nanobind version and fail when it is not installed, even when we have a submodule.

Or maybe this is just the case when the build environment is not connected to the internet? We can add the package to nix though, it is already packaged.

diff --git a/flake.nix b/flake.nix
index 05677219..3ea2dc1c 100644
--- a/flake.nix
+++ b/flake.nix
@@ -123,6 +123,7 @@
                 tbb
                 glm
                 clipper2
+                nanobind
               ];
               nativeBuildInputs = with pkgs; [
                 cmake

[cjmayo]

flake.nix update worked.

I'll have a look at FetchContent.

[cjmayo]

Now using FetchContent instead of a submodule/

[pca006132]

I think for nix, there is no python nanobind package. I think we can do find_package(nanobind 1.8.0 CONFIG REQUIRED), and if nanobind_FOUND is not defined we can do the fetch content?

[cjmayo]

It is already trying to FetchContent:

manifold-tbb> -- nanobind not found, downloading from source
manifold-tbb> CMake Error at /nix/store/q1nssraba326p2kp6627hldd2bhg254c-cmake-3.29.2/share/cmake-3.29/Modules/ExternalProject.cmake:2945 (message):
manifold-tbb>   error: could not find git for clone of nanobind-populate

[cjmayo]

It seems like this works:

@@ -35,7 +35,7 @@
                 cmake
                 ninja
                 (python3.withPackages
-                  (ps: with ps; [ trimesh pytest ]))
+                  (ps: with ps; [ nanobind trimesh pytest ]))
                 gtest
                 pkg-config
               ]) ++ build-tools;

but build_nix_python is still broken.

[cjmayo]

OK:

@@ -133,6 +133,7 @@
                 pkg-config
               ];
               checkInputs = [
+                nanobind
                 trimesh
                 pytest
               ];