Premake override for Vcpkg - premake

Question

I would like to be able to create a custom override to add a VcpkgConfiguration Property based on our current configuration.
We have a C++ project that uses Premake and vcpkg. We have found vcpkg to conflict with other projects that include their own versions of similar libraries, so we cannot use the global integration that it provides. Instead we have added it as a sub-module to our project and linked it through premake with a custom override:
p.override(p.vstudio.vc2010, "importExtensionTargets", function(base, prj)
p.push('<ImportGroup Label="ExtensionTargets">')
p.callArray(p.vstudio.vc2010.elements.importExtensionTargets, prj)
p.pop('</ImportGroup>')
p.push('<ImportGroup Label="ExtensionTargets">')
p.w('<Import Project="$(SolutionDir)External/vcpkg/scripts/buildsystems/msbuild/vcpkg.targets"/>')
p.pop('</ImportGroup>')
end)
Unfortunately we do not use the regular "Debug" or "Release" configurations in our project, so vcpkg by default does not link correctly. To get past that problem, we modified the vcpkg.targets file to recognize our configuration in a local branch. This is not ideal, as it forces us to rebase our branch off vcpkg in order to update it, and could potentially conflict if that file is ever modified in their repo.
The targets file allows you to set the VcpkgConfiguration property before including the target, which is what we would like to do.
Basically what we would like is to be able to call a command through the filters like this:
filter {"configurations:<SomeConfiguration>"}
VcpkgConfig "Debug"
Which would add this inside the propertygroup
<VcpkgConfiguration>Debug</VcpkgConfiguration>
How can we accomplish this?

Answer 1

The problem seems to be that importExtensionTargets is per project but you want this per configuration.
You can try to register your key word
api.register {
name= "VcpkgConfig",
scope = "config",
kind = "string",
}
then in your custom function
-- loop over all configurations
for _, cfgName in ipairs(prj.configurations) do
-- find config
local cfg = project.findClosestMatch(prj, cfgName)
if cfg.VcpkgConfig then
p.push('<ImportGroup Label="ExtensionTargets">')
p.push('<VcpkgConfiguration>'.. cfg.VcpkgConfig .. '</VcpkgConfiguration>')
p.w('<Import Project="$(SolutionDir)External/vcpkg/scripts/buildsystems/msbuild/vcpkg.targets"/>')
p.pop('</ImportGroup>')
end
Not tested.
Would this work ?