[feature] Add --build parameter to build all packages not in local cache

On our Linux CI/CD server I want to prevent that we download binary packages that are built against a newer libc version. The easiest solution for that seems to build all packages that are not in the local cache from source. However as fas as I can find the --build option for conan install, conan create etc doesn’t support this build policy yet.

I think it would be useful to allow conan install .... --build=not_in_cache. The not_in_cache parameter is of course only an example and can be changed as fit.

• I’ve read the CONTRIBUTING guide.

[wdobbe]

Thanks. We already have a repo for conan config install, I will add our settings.yml to it.

[memsharded]

Hi @wdobbe

I think the right, long term solution if you want to control, track and manage properly the differences of the new libc version is not this way, but adding a custom sub-setting that will represent this difference: https://docs.conan.io/en/latest/extending/custom_settings.html#adding-new-sub-settings.

This can be very straightforward, only add the subsetting to the settings.yml, then to the profiles that you are using, no need to change the recipes, and if you want to have backward binary package_id compatibility, adding a None value for the subsetting will make it. Then --build=missing will always do the right thing, safely and optimally.