using-git-spice

Using git-spice

Overview

git-spice (gs) is a CLI tool for managing stacked Git branches and their Change Requests.

Core principle: git-spice tracks branch relationships (stacks) and automates rebasing/submitting dependent branches.

Key Concepts

Stack terminology:

• Stack: All branches connected to current branch (both upstack and downstack)
• Upstack: Branches built on top of current branch (children and descendants)
• Downstack: Branches below current branch down to trunk (parents and ancestors)
• Trunk: Main integration branch (typically main or master)

Example stack:

┌── feature-c     ← upstack from feature-b
├── feature-b     ← upstack from feature-a, downstack from feature-c
├── feature-a     ← downstack from feature-b
main (trunk)

When on feature-b:

• Upstack: feature-c
• Downstack: feature-a, main
• Stack: feature-a, feature-b, feature-c

Quick Reference

Task	Command	Notes
Initialize repo	gs repo init	Required once per repo. Sets trunk branch.
Create stacked branch	gs branch create <name>	Creates branch on top of current. Use gs bc shorthand.
View stack	gs log short	Shows current stack. Use gs ls or gs log long (gs ll) for details.
Submit stack as PRs	gs stack submit	Submits entire stack. Use gs ss shorthand.
Submit upstack only	gs upstack submit	Current branch + children. Use gs us s shorthand.
Submit downstack only	gs downstack submit	Current branch + parents to trunk. Use gs ds s shorthand.
Rebase entire stack	gs repo restack	Rebases all tracked branches on their bases.
Rebase current stack	gs stack restack	Rebases current branch's stack. Use gs sr shorthand.
Rebase upstack	gs upstack restack	Current branch + children. Use gs us r shorthand.
Move branch to new base	gs upstack onto <base>	Moves current + upstack to new base.
Sync with remote	gs repo sync	Pulls latest, deletes merged branches.
Track existing branch	gs branch track [branch]	Adds branch to git-spice tracking.
Delete branch	gs branch delete [branch]	Deletes branch, restacks children. Use gs bd shorthand.

Command shortcuts: Most commands have short aliases. Use gs --help to see all aliases.

Common Workflows

These workflows apply to single-repository scenarios. For features spanning multiple repositories, see Multi-Repo Workflows below.

Workflow 1: Create and Submit Stack

# One-time setup
gs repo init
# Prompt asks for trunk branch (usually 'main')

# Create stacked branches
gs branch create feature-a
# Make changes, commit with git
git add . && git commit -m "Implement A"

gs branch create feature-b  # Stacks on feature-a
# Make changes, commit
git add . && git commit -m "Implement B"

gs branch create feature-c  # Stacks on feature-b
# Make changes, commit
git add . && git commit -m "Implement C"

# View the stack
gs log short

# Submit entire stack as PRs
gs stack submit
# Creates/updates PRs for all branches in stack

Workflow 2: Update Branch After Review

# You have feature-a → feature-b → feature-c
# Reviewer requested changes on feature-b

git checkout feature-b
# Make changes, commit
git add . && git commit -m "Address review feedback"

# Rebase upstack (feature-c) on updated feature-b
gs upstack restack

# Submit changes to update PRs
gs upstack submit
# Note: restack only rebases locally, submit pushes and updates PRs

CRITICAL: Don't manually rebase feature-c! Use gs upstack restack to maintain stack relationships.

Workflow 3: Sync After Upstream Merge

# feature-a was merged to main
# Need to update feature-b and feature-c

# Sync with remote (pulls main, deletes merged branches)
gs repo sync

# Restack everything on new main
gs repo restack

# Verify stack looks correct
gs log short

# Push updated branches
gs stack submit

CRITICAL: Don't rebase feature-c onto main! After feature-a merges:

• feature-b rebases onto main (its new base)
• feature-c rebases onto feature-b (maintains dependency)

When to Use Git vs git-spice

Use git-spice for:

• Creating branches in a stack: gs branch create
• Rebasing stacks: gs upstack restack, gs repo restack
• Submitting PRs: gs stack submit, gs upstack submit
• Viewing stack structure: gs log short
• Deleting branches: gs branch delete (restacks children)

Use git for:

• Making changes: git add, git commit
• Checking status: git status, git diff
• Viewing commit history: git log
• Individual branch operations: git checkout, git switch

Never use git rebase directly on stacked branches - use git-spice restack commands to maintain relationships.

Common Mistakes

Mistake	Why It's Wrong	Correct Approach
Rebasing child onto trunk after parent merges	Breaks stack relationships, creates conflicts	Use gs repo sync && gs repo restack
Using git push --force after changes	Bypasses git-spice tracking	Use gs upstack submit or gs stack submit
Manually rebasing with git rebase	git-spice doesn't track the rebase	Use gs upstack restack or gs stack restack
Running gs stack submit on wrong branch	Might submit unintended branches	Check gs log short first to see what's in stack
Forgetting gs repo init	Commands fail with unclear errors	Run gs repo init once per repository
Using stack when you mean upstack	Submits downstack branches too (parents)	Use upstack to submit only current + children
Assuming restack runs automatically	After commits, stack can drift	Explicitly run gs upstack restack after changes

Red Flags - Check Documentation

• Confused about stack/upstack/downstack scope
• About to run git rebase on a tracked branch
• Unsure which submit command to use
• Getting "not tracked" errors

When uncertain, run gs <command> --help for detailed usage.

Authentication and Setup

First time setup:

# Authenticate with GitHub/GitLab
gs auth login
# Follow prompts for OAuth or token auth

# Initialize repository
gs repo init
# Sets trunk branch and remote

# Verify setup
gs auth status

Handling Conflicts

If gs upstack restack or gs repo restack encounters conflicts:

1. Resolve conflicts using standard git workflow (git status, edit files, git add)
2. Continue with git rebase --continue
3. git-spice will resume restacking remaining branches
4. After resolution, run gs upstack submit to push changes

If you need to abort a restack, check gs --help for recovery options.

Multi-Repo Workflows

Per-Repo Stacking Limitation

Git-spice operates on ONE repository at a time. In multi-repo spectacular features:

• Each repo has its own independent stack
• Cannot create a cross-repo linear stack
• Branches stay within their respective repos

Multi-Repo PR Submission

For features spanning multiple repos, submit PRs in phase order:

Phase-ordered submission:

# Phase 1 repos first (foundation)
cd shared-lib
gs stack submit
cd ..

# Phase 2 repos second
cd backend
gs stack submit
cd ..

# Phase 3 repos last (depends on earlier phases)
cd frontend
gs stack submit
cd ..

Why phase order matters:

• Phase 1 changes (e.g., shared types) must merge before Phase 2 consumers
• Prevents broken builds from missing dependencies
• Mirrors the execution order during development

Multi-Repo Stack Visualization

View stacks across all repos:

# From workspace root
for repo in backend frontend shared-lib; do
  echo "=== $repo ==="
  cd $repo && gs log short && cd ..
done

Multi-Repo Sync

After PRs merge, sync all repos:

# From workspace root
for repo in backend frontend shared-lib; do
  echo "Syncing $repo..."
  cd $repo && gs repo sync && cd ..
done

Coordinating Cross-Repo Dependencies

If PR in repo A depends on PR in repo B:

1. Merge repo B's PR first
2. Update repo A to use the merged changes
3. Then merge repo A's PR

Example:

shared-lib: PR for new types
  ↓ (merge first)
backend: PR using new types
  ↓ (merge second)
frontend: PR using backend API
  ↓ (merge third)

Additional Resources

• Full CLI reference: gs --help
• Command-specific help: gs <command> --help
• Configuration: gs config --help
• Official docs: https://abhinav.github.io/git-spice/