git-assembler 1.4 was just released. This version brings full worktree support. Checked-out branches are correctly updated/rebuilt from any tree when referenced in the current assembly. This allows the developer to use worktrees as automated "patch testing ground" across multiple mainlines, either for local use or CI.
git-assembler can perform automatic merge and rebase operations following a simple declarative script. Like "make", but for branches. You can use git-assembler to create a branch which is a combination of patches using various strategies and keep it always updated.
Documentation and links are available at:
https://www.thregr.org/~wavexx/software/git-assembler/
The source itself:
https://gitlab.com/wavexx/git-assembler