luarocks-cmake-packaging

name	luarocks-cmake-packaging
description	Create luarocks rockspec with cmake build, dynamic backend .so copying, cross-platform
source	auto-skill
extracted_at	2026-06-05T14:22:08.096Z

Luarocks + CMake Packaging

Problem: luarocks cmake build type calls cmake --install which fails on FetchContent codec dependencies (ogg/flac/vorbis). Also, install.lib doesn't support glob patterns for dynamic backend discovery.

Solution: Use command build type with custom build_command + install section.

Rockspec template (insight-1.0-1.rockspec):

build = {
    type = "command",
    build_command = [[
        cmake -S . -B build.luarocks \
            -DCMAKE_BUILD_TYPE=Release \
            -DINSIGHT_BUILD_TESTS=OFF \
            -DINSIGHT_BUILD_DEMOS=OFF \
            -DINSIGHT_BUILD_BINDINGS=ON \
            -DINSIGHT_BUILD_PYTHON_BINDING=OFF \
            -DINSIGHT_BUILD_JULIA_BINDING=OFF \
            -DINSIGHT_BUILD_LUA_BINDING=ON \
            -DINSIGHT_WITH_CUDA=ON \
            -DINSIGHT_USE_FFTW3=ON \
            -DINSIGHT_USE_OPENBLAS=ON \
            -DINSIGHT_USE_MATPLOT=ON \
            -DLUA_INCLUDE_DIR="$(LUA_INCDIR)" \
            && cmake --build build.luarocks -j 24
    ]],
    install = {
        lua = {
            ["insight"] = "bindings/lua/insight/init.lua",
            ["insight.init"] = "bindings/lua/insight/init.lua",
        },
        lib = {
            "build.luarocks/bindings/lua/_insight",
        },
    },
}

Key decisions:

• command type avoids cmake --install (which fails on codec deps)
• install.lib only lists _insight (luarocks creates symlink)
• Backend .so files are copied by cmake POST_BUILD, NOT by luarocks
• LUA_INCLUDE_DIR="$(LUA_INCDIR)" passes luarocks' Lua headers to cmake
• Do NOT use $(LUA_LIBDIR) — not always set by luarocks

Backend .so handling:

• cmake POST_BUILD copies libinsight_*_backend.so to bindings/lua/
• Lua init.lua finds backends via package.cpath search + symlink resolution
• No hardcoded backend names in rockspec

Parallel build: CMAKE_BUILD_PARALLEL_LEVEL=24 or MAKEFLAGS="-j24"

Testing:

luarocks --lua-version 5.3 make bindings/lua/insight-1.0-1.rockspec LUA_DIR=/usr --local
eval $(luarocks path --lua-version 5.3)
lua5.3 -e 'local ins = require("insight"); print(ins.zeros({3,3}))'

Why: cmake build type in luarocks calls cmake --install which triggers codec deps install rules. command type gives full control.