Upstream backports --------------------------- There are situations where it is necessary to backport a patch to an earlier version of NetworkManager. In order to do the backport, use `git cherry-pick -x`. Please use the commit from the next stable branch. If the commit is not on that branch then it is also necessary to backport to that branch. Example: We want to backport commit 323e18276894591712a5e29f6e907562c79c5216 from `main` (1.33) branch to `nm-1-30` branch. In order to do that, we must search if this bug has been backported to 1.32. `git log --all --grep "323e18276894591712a5e29f6e907562c79c5216"` In case the backport to 1.32 is missing it would not show anything so please do the backport to 1.32 first. If the backport is done, the output should be similar to: ``` commit c94b1c43d4b5c5b88d67d7966d23a005028e78d8 Author: Thomas Haller Date: Wed Sep 1 09:30:29 2021 +0200 cloud-setup: return structure for get_config() result instead of generic hash table Returning a struct seems easier to understand, because then the result is typed. Also, we might return additional results, which are system wide and not per-interface. (cherry picked from commit 323e18276894591712a5e29f6e907562c79c5216) ``` In this case, the commit that should be backported is c94b1c43d4b5c5b88d67d7966d23a005028e78d8. ### Resolving conflicts To find conflicts when doing a backporting in NetworkManager is very common but we do not resolve the conflicts manually. Instead, we abort the current cherry-pick and search for the commit that introduced the changes that are causing the conflict and backport it too. We only resolve the conflict manually if the extra commit introduces a lot of unnecessary changes or excesive code changes which is not common. ### Backporting API NetworkManager allows the users to build their application against the latest stable release and then run it against a newer release without relinking. To allow this, we need to guarantee that after we release a version that includes a new libnm linker version, then any release done after that point with a higher version number contains that linker version with the same symbols. In practice when we want to backport new API from main we have two options: - if the new API hasn't been included in a stable release of NetworkManager, then we can just backport the API to the old branch and pretend it was introduced there. For example, 8763e6da9c5adb3c4ccf3b2713dbcc25a91c5ede introduces new API on main during the 1.21 development cycle; 1.22 is not released yet. Then the symbol is backported to nm-1-20 before 1.20.6 with commit 90671a30b771d418953bd021d50c3cc43f253e6e. The symbol on main branch is then adjusted with 551fd3e28f6b142bd57eefacfaf96b8fb8e309dd. Note that at this point 1.20.6 must be released before 1.22.0. - if the new API is already included in a stable release, we backport the API to the old branch and then duplicate the symbol on main with both versions. For example, 2e2ff6f27aa1bfa7a27d49980b319873240ec84b introduces new API on main, which is released as 1.12.0. The API is backported to 1.10.14 in commit 19d7e66099ee43f47d6be0e740dc710fc365d200. Then, on main we add duplicate symbols with commit 5eade4da11ee38a0e7faf4a87b2c2b5af07c5eeb.