Porting PostHog/code PRs to the monorepo

PostHog/code's main is frozen after the desktop import. The tree lives at products/desktop/ as a verbatim copy of the source at a pinned SHA, so open PRs on PostHog/code can no longer land there and are remade as monorepo PRs instead. products/desktop/MIGRATION.md is the contract for the import: its pinned SHA, drift list and workflow mapping table are authoritative over anything restated here. Read it before resolving any conflict.

Path mapping: <path> in PostHog/code becomes products/desktop/<path>. The one exception is .github/, which was not imported: source workflows were transformed into root .github/workflows/desktop-*.yml files per the mapping table and transform rules in MIGRATION.md.

Scope the sweep

Resolve the author's GitHub login first (gh api user --jq .login when it is the requester). Then enumerate:

gh pr list --repo PostHog/code --author <login> --state open \
  --json number,title,isDraft,headRefName,url,body

For each PR decide: port, skip or flag.

• Skip a PR whose change already exists in products/desktop/ (superseded, or landed upstream and arrived via a resync). Check the tree, not just the PR state.
• Never port a PR that was merged into PostHog/code. Merged-after-pin changes arrive through the resync protocol in MIGRATION.md, and porting them too would duplicate the diff.
• When source PRs stack on each other, port in dependency order and stack the monorepo branches the same way.

The skill works the same for a single PR; the sweep is just the loop.

Port one PR

Work on a branch off fresh master, one monorepo PR per source PR. Reusing the source head branch name keeps the pair easy to correlate.

1. Fetch the patch series, plus the source objects the 3-way fallback needs:

PATCH=$(mktemp)
gh pr diff <N> --repo PostHog/code --patch > "$PATCH"
git fetch https://github.com/PostHog/code.git refs/pull/<N>/head

2. Apply with authorship preserved:

git am -3 --empty=drop --directory=products/desktop/ \
  --exclude='products/desktop/.github/*' \
  --exclude='products/desktop/pnpm-lock.yaml' \
  --exclude='products/desktop/packages/agent/pnpm-lock.yaml' \
  "$PATCH"

--exclude matches after --directory is prepended, so the patterns carry the products/desktop/ prefix. git am keeps each commit's original author and message; the commits are created and signed by you, which satisfies the signed-commit ruleset while crediting the source author. On conflict, resolve and git am --continue; git am --abort resets. The 3-way merge only works because step 1 fetched the source PR's objects.

3. Re-derive the excluded paths when the PR touched them:

• .github/**: look the workflow up in MIGRATION.md's mapping table. If it is in the dropped table the change is moot. Otherwise re-apply the source change to the ported root desktop-*.yml by following the transform rules, and invoke /authoring-ci-workflows before editing.
• Lockfiles: the monorepo copies carry local override pins from the drift list, so source lockfile hunks silently undo security pins. Land the package.json change, then regenerate from products/desktop/ with pnpm install --lockfile-only, minding the minimumReleaseAge notes in MIGRATION.md.

4. Treat conflicts in drift-listed files (local security patches, pnpm-workspace.yaml overrides) as intentional monorepo divergence: keep the monorepo side and re-apply the PR's intent on top of it.

5. Verify from products/desktop/: pnpm install --frozen-lockfile, pnpm typecheck and pnpm --filter <pkg> test for the packages the PR touches. The desktop CI suite runs on the monorepo PR itself.

Open the monorepo PR

• Title: keep the source title when it fits the monorepo's conventional-commit format; otherwise fix it up (desktop scope).
• Body: use .github/pull_request_template.md. Carry the original description over, rewriting bare #N references as PostHog/code#N so they do not resolve to unrelated monorepo PRs. State "Ports PostHog/code#N" so the pair is linked.
• Preserve draft state and assign the original author.
• Do not close or comment on the source PR without the author's say-so. The clean sequence is: link the monorepo PR from the source PR, then close the source once the port merges.

Report

End a sweep with one line per source PR: ported to #X, skipped (why) or flagged for a human (why). Never silently drop a PR from the sweep.