Overview

Merge origin/main into the current branch. Follow every step whether or not the merge conflicts: a clean merge still ends with the sanity check.

Procedure

1. Fetch and merge with zdiff3

If the branch is on origin, pull it first: CI's tidy job may have pushed chore: tidy onto it. If that pull conflicts, take it through steps 2 and 3, then start again here, so origin/main is merged too. Then move the checked-out submodules to the pointers the merge recorded, so the next git add -A does not stage a stale checkout.

b=$(git branch --show-current)
if git ls-remote --exit-code --heads origin "$b" > /dev/null; then
  git pull --no-rebase origin "$b" || exit 1   # a conflict stops here
fi
git fetch origin main
git -c merge.conflictstyle=zdiff3 merge origin/main
git submodule update --recommend-shallow

2. If conflicts exist, commit them as-is

If the merge produces conflicts, commit the conflict markers without resolving them first. This records the raw conflict state in a dedicated commit, separate from the resolution.

git add -A
git diff --cached origin/main -- vendor
git commit -m "merge origin/main (conflicts unresolved)"

The vendor diff prints nothing unless the branch bumps a submodule itself. Anything else is a stale checkout that git add -A staged, reverting main's bump. Restore main's pointer for each such path before committing, and check again after every git add -A, step 3's included:

git update-index --cacheinfo 160000,"$(git rev-parse origin/main:vendor/wasmtime)",vendor/wasmtime

3. Resolve conflicts

After committing the unresolved state:

1. Read each conflicted file and understand both sides of the conflict
2. Resolve conflicts in code files (remove conflict markers, choose correct code)
3. For generated files (golden fixtures, generated parsers, …) that conflict, regenerate them by re-running their generator and commit the fresh output — do not hand-resolve the markers or defer them (see "Generated files" below)
4. Stage and commit the resolution:

git add -A
git diff --cached origin/main -- vendor   # as in step 2
git commit -m "resolve merge conflicts"

4. Run mise run test for sanity check

CI applies clippy and format, so a quick sanity check is sufficient.

Important

• Always use -c merge.conflictstyle=zdiff3 so the merge base is visible in conflict markers (with zealous zdiff3 reducing noise)
• Always commit the unresolved conflicts first, then resolve in a separate commit — this preserves a clear record of what the conflicts looked like vs how they were resolved
• Do NOT squash the two commits together

Generated files

• Always regenerate golden / generated files and commit. Re-run the generator (do not hand-resolve the markers) and commit its output. Do not skip them or defer them to on-task-done / CI.
• Never silently discard generated output (e.g. git restore to clean the tree or quiet a hook). Commit it, or ask. Discarding generated work without asking is always wrong.