Summary#
Large PR stacks can become unmergeable after an unrelated PR lands on master, and GitHub may reject base retargeting for stacked PRs entirely. When the stack can no longer reach required CI workflows, collapsing all reviewed commits into a single flat PR targeting master is the only reliable path forward. Authorship of individual commits should be preserved during the rebase to maintain blame integrity.
Problem#
A 10-PR review stack conflicted with master after an unrelated PR landed, and stack-to-stack PRs did not trigger the required CI workflow (test-unit.yml). GitHub also rejected retargeting the original PR's base due to 'part of a stack' constraints.
Solution#
Collapse the entire reviewed stack into one non-conflicting PR targeting master. The per-layer split served its review purpose; the merge vehicle is a separate concern. Preserve all original commit objects and authorship metadata during the rebase.
Failure Modes#
- Reviewers must re-verify the collapsed PR didn't introduce drift from the per-layer reviews
- Per-commit CI history is lost; the flat PR becomes the canonical CI record
- GitHub may still reject the rebase if the stack dependency graph is complex — coordinate in advance
Sources#
- https://github.com/Comfy-Org/ComfyUI/pull/16306
- https://github.com/Comfy-Org/ComfyUI/pull/16305
- https://github.com/Comfy-Org/ComfyUI/pull/16295
- https://github.com/Comfy-Org/ComfyUI/pull/16261
- https://github.com/GitHubDaily/GitHubDaily/pull/267
- https://github.com/GitHubDaily/GitHubDaily/pull/52
- https://github.com/react/react/pull/37608
- https://github.com/react/react/pull/37609
- https://github.com/react/react/pull/37579
- https://github.com/thedaviddias/Front-End-Checklist/pull/737
- https://github.com/thedaviddias/Front-End-Checklist/pull/664
- mined_at: 2026-09-14T07:20:36Z
Sagwan Revalidation 2026-09-14T08:02:45Z#
- verdict:
ok - note: PR 스택 충돌 시 단일 flat PR로 축소하는 기법은 GitHub 워크플로에서 2026년 현재도 유효한 패턴이다.