Interactive Rebase & Worktrees

Q: Should spike branch merge or rebase onto main before PR?

git merge origin/main into spike before PR is safer for long spikes. Interactive rebase onto main produces linear history but costs conflict resolution time.

Q: Can CI run on worktree branches?

Yes - worktrees push to same origin. Branch spike/sdk-57-upgrade triggers same GitHub Actions as any remote branch.

Q: What commits belong in one squash?

One logical unit: one ticket or one SDK bump. Separate feat from chore(sdk) if reviewers need to bisect later.

A cookbook for parallel SDK upgrade spikes using git worktree and interactive rebase - so expo upgrade does not freeze main and your stash list does not become archaeology.

Recipe

Quick-reference recipe card - copy-paste ready.

# From primary clone - add SDK spike worktree (sibling directory)
cd ~/WEBDEV/ShipApp
git fetch origin
git worktree add ../ShipApp-sdk57-spike -b spike/sdk-57-upgrade origin/main

# Spike worktree - upgrade in isolation
cd ../ShipApp-sdk57-spike
npm ci
npx expo install expo@~57.0.4 --fix
npx expo-doctor
npm run typecheck && npm run test -- --ci

# Primary clone - keep shipping features on main
cd ~/WEBDEV/ShipApp
git checkout main
git checkout -b feat/SHIP-501-settings-redesign
# Metro on default 8081 - spike uses 8082 (see below)

# Before PR - squash fixup commits on feature branch
git checkout feat/SHIP-501-settings-redesign
git fetch origin && git rebase -i origin/main
# Mark WIP commits as squash/fixup; keep one feat commit

# After spike validated - remove worktree
cd ~/WEBDEV/ShipApp
git worktree remove ../ShipApp-sdk57-spike

When to reach for this:

Expo SDK upgrade spanning days while features must merge to main.
Native prebuild diff you need to compare side-by-side with production branch.
Long-running spike (new navigation library) without blocking teammates' npm ci.
PR cleanup - ten "fix lint" commits should be one commit before review.

When to avoid:

Shared release/* or hotfix/* branches others have checked out - rebase rewrites history.
Already-pushed branch others based work on - coordinate or merge instead of rebase.
Disk-constrained laptop - two full node_modules trees cost gigabytes.

Working Example

Scenario: ShipApp runs Expo SDK 56 in production. Team needs SDK 57 spike while feat/* branches land daily on main.

Step 1 - Create spike worktree

cd ~/WEBDEV/ShipApp
git pull --ff-only origin main
git worktree add ../ShipApp-sdk57-spike -b spike/sdk-57-upgrade origin/main
git worktree list

/Users/csjcode/WEBDEV/ShipApp              abc1234 [main]
/Users/csjcode/WEBDEV/ShipApp-sdk57-spike  abc1234 [spike/sdk-57-upgrade]

Both directories share one .git object store - branches differ, disks separate.

Step 2 - Isolate Metro ports

# ../ShipApp-sdk57-spike/.env.local (gitignored)
EXPO_PACKAGER_PORT=8082

cd ../ShipApp-sdk57-spike
npm ci
npx expo start --port 8082

Primary clone keeps npx expo start on 8081 - no "port already in use" collisions.

Step 3 - Run upgrade with checkpoint commits

cd ../ShipApp-sdk57-spike
 
npx expo install expo@~57.0.4 --fix
git add package.json package-lock.json
git commit -m "chore(sdk): bump expo to SDK 57 [SPIKE-57]"
 
npx expo prebuild --clean
git add ios android
git commit -m "chore(native): prebuild after SDK 57 [SPIKE-57]"
 
npm run typecheck
# fix breaks...
git commit -am "fix(types): navigation params after RN 0.86 [SPIKE-57]"

WIP commits are fine on spike branch - interactive rebase before opening PR.

Step 4 - Parallel feature work in primary clone

cd ~/WEBDEV/ShipApp
git checkout -b feat/SHIP-501-settings-redesign
# unaffected by spike's package.json - separate node_modules
npm ci
npm run test -- --ci
git push -u origin feat/SHIP-501-settings-redesign

Teammates never pull half-upgraded SDK from main.

Step 5 - Interactive rebase before PR

Feature branch accumulated noise:

git checkout feat/SHIP-501-settings-redesign
git log --oneline origin/main..HEAD

a1b2c3d fix typo
d4e5f6g fix lint
g7h8i9j feat(settings): redesign layout [SHIP-501]
j1k2l3m wip

git rebase -i origin/main

In the editor, reorder and mark:

pick g7h8i9j feat(settings): redesign layout [SHIP-501]
squash j1k2l3m wip
squash d4e5f6g fix lint
squash a1b2c3d fix typo

git push --force-with-lease origin feat/SHIP-501-settings-redesign

--force-with-lease - safer than --force; fails if remote advanced
Only rewrite your feature branches - never main, release/*, hotfix/*

Step 6 - Finish spike and land on main

cd ../ShipApp-sdk57-spike
npm run lint && npm run typecheck && npm run test -- --ci
npx expo-doctor

Squash spike commits for review:

git rebase -i origin/main
# squash all SPIKE-57 commits into one:
# chore(sdk): upgrade to Expo SDK 57 [SPIKE-57]

git push -u origin spike/sdk-57-upgrade
# Open PR → main; full device matrix + EAS preview build required

After merge:

cd ~/WEBDEV/ShipApp
git pull --ff-only origin main
git worktree remove ../ShipApp-sdk57-spike
git branch -d spike/sdk-57-upgrade   # if merged

Trigger preview build on PR for SDK PRs - Expo Go alone misses native changes.

Rebase Safety Matrix

Branch type	Interactive rebase?	Force push?
`feat/*` (solo)	Yes	`--force-with-lease` OK
`spike/*`	Yes	`--force-with-lease` OK
`main`	No	Never
`release/*`	No	Breaks RC audit
`hotfix/*`	No	Cherry-pick instead
Shared `feat/*`	Coordinate	Prefer merge

# Abort a rebase gone wrong
git rebase --abort
 
# Recovery reflog
git reflog | head -20
git checkout -b recovery-branch HEAD@{3}

Worktree Commands Reference

git worktree list
git worktree add ../path -b new-branch start-point
git worktree remove ../path
git worktree prune   # clean stale metadata
 
# Cannot remove worktree with uncommitted changes
git -C ../ShipApp-sdk57-spike status

# Optional: shared node_modules via pnpm (advanced)
# Prefer full npm ci per worktree for fidelity with CI

Gotchas

One branch checked out in two worktrees - Git forbids this. Fix: Different branch per worktree directory.
Rebasing after PR review started - Invalidates review comments on old SHAs. Fix: Rebase before requesting review, or merge main instead.
Spike merges without expo-doctor in CI - Hidden dependency skew. Fix: Add doctor step to PR checks.
Forgotten worktree consumes disk - git worktree list monthly. Fix: git worktree remove + git worktree prune.
Interactive rebase on merge commits - Confusing conflicts. Fix: git rebase -i --rebase-merges or avoid merge commits on feature branches.

Alternatives

Alternative	Use When	Don't Use When
`git stash`	30-minute context switch	Multi-day SDK spike
Second full clone	Simple mental model	Double fetch time and disk
Feature flags on main	Small SDK delta	Native folder overhaul
Draft PR from spike	Visibility without merge	Still blocks CI if targeting main early

FAQs

worktree vs second git clone?

Worktrees share object database - faster, less disk. Second clone is simpler but duplicates .git history. Prefer worktrees for same-repo parallel branches.

How many worktrees are practical?

Two or three (main + spike + hotfix investigation). More than that - disk and mental overhead exceed benefit.

Should spike branch merge or rebase onto main before PR?

git merge origin/main into spike before PR is safer for long spikes. Interactive rebase onto main produces linear history but costs conflict resolution time.

Can CI run on worktree branches?

Yes - worktrees push to same origin. Branch spike/sdk-57-upgrade triggers same GitHub Actions as any remote branch.

What commits belong in one squash?

One logical unit: one ticket or one SDK bump. Separate feat from chore(sdk) if reviewers need to bisect later.

Git Basics for Mobile Teams - when not to touch release branches
GitHub Flow & Release Branches - hotfix lanes avoid rebase
GitHub Actions Integration - SDK PR requires preview build evidence
Preview Builds on PRs - native validation for SDK upgrades
EAS Workflows - expo-doctor before type: build
Mobile CI/CD Basics - PR checks spike branches use
Git & GitHub Best Practices - 25-item summary

Stack versions: This page was written for React 19.2.3, React Native 0.86.0, and Expo SDK 57 (expo ~57.0.4).

Recipe

Quick-reference recipe card - copy-paste ready.

# From primary clone - add SDK spike worktree (sibling directory)
cd ~/WEBDEV/ShipApp
git fetch origin
git worktree add ../ShipApp-sdk57-spike -b spike/sdk-57-upgrade origin/main

# Spike worktree - upgrade in isolation
cd ../ShipApp-sdk57-spike
npm ci
npx expo install expo@~57.0.4 --fix
npx expo-doctor
npm run typecheck && npm run test -- --ci

# Primary clone - keep shipping features on main
cd ~/WEBDEV/ShipApp
git checkout main
git checkout -b feat/SHIP-501-settings-redesign
# Metro on default 8081 - spike uses 8082 (see below)

# Before PR - squash fixup commits on feature branch
git checkout feat/SHIP-501-settings-redesign
git fetch origin && git rebase -i origin/main
# Mark WIP commits as squash/fixup; keep one feat commit

# After spike validated - remove worktree
cd ~/WEBDEV/ShipApp
git worktree remove ../ShipApp-sdk57-spike

When to reach for this:

Expo SDK upgrade spanning days while features must merge to main.
Native prebuild diff you need to compare side-by-side with production branch.
Long-running spike (new navigation library) without blocking teammates' npm ci.
PR cleanup - ten "fix lint" commits should be one commit before review.

When to avoid:

Shared release/* or hotfix/* branches others have checked out - rebase rewrites history.
Already-pushed branch others based work on - coordinate or merge instead of rebase.
Disk-constrained laptop - two full node_modules trees cost gigabytes.

Working Example

Scenario: ShipApp runs Expo SDK 56 in production. Team needs SDK 57 spike while feat/* branches land daily on main.

Step 1 - Create spike worktree

cd ~/WEBDEV/ShipApp
git pull --ff-only origin main
git worktree add ../ShipApp-sdk57-spike -b spike/sdk-57-upgrade origin/main
git worktree list

/Users/csjcode/WEBDEV/ShipApp              abc1234 [main]
/Users/csjcode/WEBDEV/ShipApp-sdk57-spike  abc1234 [spike/sdk-57-upgrade]

Both directories share one .git object store - branches differ, disks separate.

Step 2 - Isolate Metro ports

# ../ShipApp-sdk57-spike/.env.local (gitignored)
EXPO_PACKAGER_PORT=8082

cd ../ShipApp-sdk57-spike
npm ci
npx expo start --port 8082

Primary clone keeps npx expo start on 8081 - no "port already in use" collisions.

Step 3 - Run upgrade with checkpoint commits

cd ../ShipApp-sdk57-spike
 
npx expo install expo@~57.0.4 --fix
git add package.json package-lock.json
git commit -m "chore(sdk): bump expo to SDK 57 [SPIKE-57]"
 
npx expo prebuild --clean
git add ios android
git commit -m "chore(native): prebuild after SDK 57 [SPIKE-57]"
 
npm run typecheck
# fix breaks...
git commit -am "fix(types): navigation params after RN 0.86 [SPIKE-57]"

WIP commits are fine on spike branch - interactive rebase before opening PR.

Step 4 - Parallel feature work in primary clone

cd ~/WEBDEV/ShipApp
git checkout -b feat/SHIP-501-settings-redesign
# unaffected by spike's package.json - separate node_modules
npm ci
npm run test -- --ci
git push -u origin feat/SHIP-501-settings-redesign

Teammates never pull half-upgraded SDK from main.

Step 5 - Interactive rebase before PR

Feature branch accumulated noise:

git checkout feat/SHIP-501-settings-redesign
git log --oneline origin/main..HEAD

a1b2c3d fix typo
d4e5f6g fix lint
g7h8i9j feat(settings): redesign layout [SHIP-501]
j1k2l3m wip

git rebase -i origin/main

In the editor, reorder and mark:

pick g7h8i9j feat(settings): redesign layout [SHIP-501]
squash j1k2l3m wip
squash d4e5f6g fix lint
squash a1b2c3d fix typo

git push --force-with-lease origin feat/SHIP-501-settings-redesign

--force-with-lease - safer than --force; fails if remote advanced
Only rewrite your feature branches - never main, release/*, hotfix/*

Step 6 - Finish spike and land on main

cd ../ShipApp-sdk57-spike
npm run lint && npm run typecheck && npm run test -- --ci
npx expo-doctor

Squash spike commits for review:

git rebase -i origin/main
# squash all SPIKE-57 commits into one:
# chore(sdk): upgrade to Expo SDK 57 [SPIKE-57]

git push -u origin spike/sdk-57-upgrade
# Open PR → main; full device matrix + EAS preview build required

After merge:

cd ~/WEBDEV/ShipApp
git pull --ff-only origin main
git worktree remove ../ShipApp-sdk57-spike
git branch -d spike/sdk-57-upgrade   # if merged

Trigger preview build on PR for SDK PRs - Expo Go alone misses native changes.

Rebase Safety Matrix

Branch type	Interactive rebase?	Force push?
`feat/*` (solo)	Yes	`--force-with-lease` OK
`spike/*`	Yes	`--force-with-lease` OK
`main`	No	Never
`release/*`	No	Breaks RC audit
`hotfix/*`	No	Cherry-pick instead
Shared `feat/*`	Coordinate	Prefer merge

# Abort a rebase gone wrong
git rebase --abort
 
# Recovery reflog
git reflog | head -20
git checkout -b recovery-branch HEAD@{3}

Worktree Commands Reference

git worktree list
git worktree add ../path -b new-branch start-point
git worktree remove ../path
git worktree prune   # clean stale metadata
 
# Cannot remove worktree with uncommitted changes
git -C ../ShipApp-sdk57-spike status

# Optional: shared node_modules via pnpm (advanced)
# Prefer full npm ci per worktree for fidelity with CI

Gotchas

One branch checked out in two worktrees - Git forbids this. Fix: Different branch per worktree directory.
Rebasing after PR review started - Invalidates review comments on old SHAs. Fix: Rebase before requesting review, or merge main instead.
Spike merges without expo-doctor in CI - Hidden dependency skew. Fix: Add doctor step to PR checks.
Forgotten worktree consumes disk - git worktree list monthly. Fix: git worktree remove + git worktree prune.
Interactive rebase on merge commits - Confusing conflicts. Fix: git rebase -i --rebase-merges or avoid merge commits on feature branches.

Alternatives

Alternative	Use When	Don't Use When
`git stash`	30-minute context switch	Multi-day SDK spike
Second full clone	Simple mental model	Double fetch time and disk
Feature flags on main	Small SDK delta	Native folder overhaul
Draft PR from spike	Visibility without merge	Still blocks CI if targeting main early

FAQs

worktree vs second git clone?

Worktrees share object database - faster, less disk. Second clone is simpler but duplicates .git history. Prefer worktrees for same-repo parallel branches.

How many worktrees are practical?

Two or three (main + spike + hotfix investigation). More than that - disk and mental overhead exceed benefit.

Should spike branch merge or rebase onto main before PR?

git merge origin/main into spike before PR is safer for long spikes. Interactive rebase onto main produces linear history but costs conflict resolution time.

Can CI run on worktree branches?

Yes - worktrees push to same origin. Branch spike/sdk-57-upgrade triggers same GitHub Actions as any remote branch.

What commits belong in one squash?

One logical unit: one ticket or one SDK bump. Separate feat from chore(sdk) if reviewers need to bisect later.

Git Basics for Mobile Teams - when not to touch release branches
GitHub Flow & Release Branches - hotfix lanes avoid rebase
GitHub Actions Integration - SDK PR requires preview build evidence
Preview Builds on PRs - native validation for SDK upgrades
EAS Workflows - expo-doctor before type: build
Mobile CI/CD Basics - PR checks spike branches use
Git & GitHub Best Practices - 25-item summary

Stack versions: This page was written for React 19.2.3, React Native 0.86.0, and Expo SDK 57 (expo ~57.0.4).

Interactive Rebase & Worktrees

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Interactive Rebase & Worktrees