update-from-upstream-main

# Update From Upstream Main Update from the canonical `remotion-dev/remotion` repository while preserving local work and published branch history. ## Workflow 1. Inspect the repository before changing it: ```bash git status --short --branch git branch --show-current git remote -v ``` Stop and report the state if an operation such as a merge or rebase is already in progress. A detached checkout is supported and must not prevent the update. If the working tree contains staged, unstaged, or untracked changes, stash them automatically and continue: ```bash git stash push --include-untracked --message "update-from-upstream-main: preserve local changes" git rev-parse stash@{0} ``` Record the created stash's commit ID so the same entry can be restored later. Do not treat uncommitted changes as a reason to stop. Do not include ignored files unless the user explicitly asks. 2. Select the canonical remote whose URL points to `remotion-dev/remotion`. Prefer `upstream` when it exists; otherwise use `origin`. If neither remote points to the canonical repository, stop and ask before adding or changing a remote. 3. Fetch the latest main branch without changing the working tree: ```bash git fetch <canonical-remote> main ``` 4. Update the checked-out branch: - On `main`, require a fast-forward: ```bash git merge --ff-only <canonical-remote>/main ``` - On a feature branch or detached checkout, merge main without opening an editor: ```bash git merge --no-edit <canonical-remote>/main ``` Do not rebase, reset, or force-push. A merge keeps published branch history intact and can be pushed normally; on a detached checkout, report that the resulting commit is still detached. 5. If the merge conflicts, resolve each file deliberately and preserve both the feature intent and upstream changes. Do not accept `ours` or `theirs` across the entire merge. Check every resolved file for leftover conflict markers before staging: ```bash rg -n '^(<{7}|={7}|>{7})' -- <resolved-files> ``` Inspect and remove any matches that are conflict markers. Then stage only the resolved files and finish the merge with: ```bash git commit --no-edit ``` 6. If step 1 created a stash, reapply it after the upstream update is complete: ```bash git stash apply --index <recorded-stash-commit> ``` Reapply the stash before reporting success or before stopping after a fetch or merge failure, provided no Git operation is still in progress. If applying the stash causes conflicts, resolve them deliberately without rerunning `git stash apply`. The stash entry remains as a recovery copy. After confirming that all stashed changes, including untracked files and their staged state, were restored, find the entry with the recorded commit ID in `git stash list --format='%gd %H'` and drop only that entry. Never pop or drop a pre-existing stash. 7. Validate the result. Always run `git diff --check` and `git diff --cached --check`. If conflicts were resolved or the combined changes could affect behavior, run the relevant package tests. For broad changes, run: ```bash bun run build bun run stylecheck ``` 8. Push only when the user asked to update a published branch or pull request. Use a normal push and stop if it is rejected: ```bash git push <canonical-remote> HEAD ``` Never force-push. 9. Report the previous and new commit, whether the checkout is detached, whether the update was a fast-forward or merge, whether local changes were stashed and successfully reapplied, any conflicts resolved, validation performed, and whether the branch was pushed.