Common Parallel Rust

Gist

• This repo exists to support synchronizing boilerplate elements across rust repos.
  • It houses branches designed for use with git merge --allow-unrelated-histories. ('parallel merge')
  • main is NOT designed for this purpose
    • main is a living repository -- which allows the impact of files changes to be directly observed
      • experience with templating systems (including one of my own) have shown that a 'template' that cannot be run and use normal tests and code verification mechanisms creates a fair bit of toil.
  • All of the branches for parallel merge are by-file subsets of main.
  • Branches:
    • simple_config
      • Rust & 3rd party config files that should see relatively little need for repo-specific changes
    • config_with_just
      • simple_config + a justfile, which is likely to see repo-specific changes and and should have any merges manually reviewed.
      • if more repo-scripting moves to cargo xtask we may also add a version of this with xtask files. (until then manual synch is expected)
    • workspace_init
      • this is close to main, and could be a living repo in its own right. It is not intended to be used to upstream changes for synchronization. It's merely an alternative to repo-templating that takes advatnage of the living repository approach already in use here.

Merging Code

REMOTE_REPO='git@github.com:dream-dasher/common_parallel_rust.git'
ALIAS_OF_REMOTE='common_par'
REMOTE_BRANCH_TO_MERGE='workspace_init|config_with_just|simple_config'
git remote add $ALIAS_OF_REMOTE $REMOTE_REPO
git fetch $LOCAL_ALIAS
git fetch --all
git merge --allow-unrelated-histories $ALIAS_OF_REMOTE/$REMOTE_BRANCH_TO_MERGE 

(opt: --strategy-option theirs) (opt: --no-commit --no-ff)

Updating Branches

The default branch-merge strategy is to only modify files and not add them. (Again, branches are by-file subsets of main)

echo 'Merging main without commit of fast-forward.'
git merge --no-commit --no-ff main
echo 'Removing all files in HEAD that are new relative to main.'
gd --name-only --diff-filter=A HEAD main |
  xargs -I _ rm -rf _
echo 'Removing all untracked files.'
git clean -f .
echo 'Re-adding all changes; only modified files should be set for merge.'
git add .

To add new files (which may have been previously ignored) the following may be necessary: (Some non-clarity around how by-file merge decisions are made relative to previous merges points.)

git restore --source=main -- <path/to/that_directory>

Caveats:

• we are comparing HEAD and main, which is correct for precisely the above, but a bit indirect
• this does not filter within-file references to non-merged files
  • by design the system should work that way
  • this can create minor issues with the justfile (e.g. where x is a cargo xtask alias for centralization of control)
    • acceptable for now
    • if we couldn't accept errors we wouldn't be running shell scripts

Cloning Repo

(using local aliases)

ghrg common_par
gh repo clone <cmd-y shift-_>
c common_par...
gfa
<for each: git checkout <x>>