---
name: upstream-merge
description: This skill should be used when incorporating upstream git changes into a local fork while preserving local intent. It provides a structured workflow for analyzing divergence, categorizing conflicts, creating triage todos for each conflict, reviewing decisions one-by-one with the user, and executing all resolutions. Triggers on "merge upstream", "incorporate upstream changes", "sync fork", or when local and remote branches have diverged significantly.
---

# Upstream Merge

Incorporate upstream changes into a local fork without losing local intent. Analyze divergence, categorize every changed file, triage conflicts interactively, then execute all decisions in a single structured pass.

## Prerequisites

Before starting, establish context:

1. **Identify the guiding principle** — ask the user what local intent must be preserved (e.g., "FastAPI pivot is non-negotiable", "custom branding must remain"). This principle governs every triage decision.
2. **Confirm remote** — verify `git remote -v` shows the correct upstream origin.
3. **Fetch latest** — `git fetch origin` to get current upstream state.

## Phase 1: Analyze Divergence

Gather the full picture before making any decisions.

**Run these commands:**

```bash
# Find common ancestor
git merge-base HEAD origin/main

# Count divergence
git rev-list --count HEAD ^origin/main   # local-only commits
git rev-list --count origin/main ^HEAD   # remote-only commits

# List all changed files on each side
git diff --name-only $(git merge-base HEAD origin/main) HEAD > /tmp/local-changes.txt
git diff --name-only $(git merge-base HEAD origin/main) origin/main > /tmp/remote-changes.txt
```

**Categorize every file into three buckets:**

| Bucket | Definition | Action |
|--------|-----------|--------|
| **Remote-only** | Changed upstream, untouched locally | Accept automatically |
| **Local-only** | Changed locally, untouched upstream | Keep as-is |
| **Both-changed** | Modified on both sides | Create triage todo |

```bash
# Generate buckets
comm -23 <(sort /tmp/remote-changes.txt) <(sort /tmp/local-changes.txt) > /tmp/remote-only.txt
comm -13 <(sort /tmp/remote-changes.txt) <(sort /tmp/local-changes.txt) > /tmp/local-only.txt
comm -12 <(sort /tmp/remote-changes.txt) <(sort /tmp/local-changes.txt) > /tmp/both-changed.txt
```

**Present summary to user:**

```
Divergence Analysis:
- Common ancestor: [commit hash]
- Local: X commits ahead | Remote: Y commits ahead
- Remote-only: N files (auto-accept)
- Local-only: N files (auto-keep)
- Both-changed: N files (need triage)
```

## Phase 2: Create Triage Todos

For each file in the "both-changed" bucket, create a triage todo using the template at [merge-triage-template.md](./assets/merge-triage-template.md).

**Process:**

1. Determine next issue ID: `ls todos/ | grep -o '^[0-9]\+' | sort -n | tail -1`
2. For each both-changed file:
   - Read both versions (local and remote)
   - Generate the diff: `git diff $(git merge-base HEAD origin/main)..origin/main -- <file>`
   - Analyze what each side intended
   - Write a recommendation based on the guiding principle
   - Create todo: `todos/{id}-pending-p2-merge-{brief-name}.md`

**Naming convention for merge triage todos:**

```
{id}-pending-p2-merge-{component-name}.md
```

Examples:
- `001-pending-p2-merge-marketplace-json.md`
- `002-pending-p2-merge-kieran-python-reviewer.md`
- `003-pending-p2-merge-workflows-review.md`

**Use parallel agents** to create triage docs when there are many conflicts (batch 4-6 at a time).

**Announce when complete:**

```
Created N triage todos in todos/. Ready to review one-by-one.
```

## Phase 3: Triage (Review One-by-One)

Present each triage todo to the user for a decision. Follow the `/triage` command pattern.

**For each conflict, present:**

```
---
Conflict X/N: [filename]

Category: [agent/command/skill/config]
Conflict Type: [content/modify-delete/add-add]

Remote intent: [what upstream changed and why]
Local intent: [what local changed and why]

Recommendation: [Accept remote / Keep local / Merge both / Keep deleted]
Reasoning: [why, referencing the guiding principle]

---
How should we handle this?
1. Accept remote — take upstream version as-is
2. Keep local — preserve local version
3. Merge both — combine changes (specify how)
4. Keep deleted — file was deleted locally, keep it deleted
```

**Use AskUserQuestion tool** for each decision with appropriate options.

**Record decisions** by updating the triage todo:
- Fill the "Decision" section with the chosen resolution
- Add merge instructions if "merge both" was selected
- Update status: `pending` → `ready`

**Group related files** when presenting (e.g., present all 7 dspy-ruby files together, not separately).

**Track progress:** Show "X/N completed" with each presentation.

## Phase 4: Execute Decisions

After all triage decisions are made, execute them in a structured order.

### Step 1: Create Working Branch

```bash
git branch backup-local-changes   # safety net
git checkout -b merge-upstream origin/main
```

### Step 2: Execute in Order

Process decisions in this sequence to avoid conflicts:

1. **Deletions first** — Remove files that should stay deleted
2. **Copy local-only files** — `git checkout backup-local-changes -- <file>` for local additions
3. **Merge files** — Apply "merge both" decisions (the most complex step)
4. **Update metadata** — Counts, versions, descriptions, changelogs

### Step 3: Verify

```bash
# Validate JSON/YAML files
cat <config-files> | python3 -m json.tool > /dev/null

# Verify component counts match descriptions
# (skill-specific: count agents, commands, skills, etc.)

# Check diff summary
git diff --stat HEAD
```

### Step 4: Commit and Merge to Main

```bash
git add <specific-files>   # stage explicitly, not -A
git commit -m "Merge upstream vX.Y.Z with [guiding principle] (vX.Y.Z+1)"
git checkout main
git merge merge-upstream
```

**Ask before merging to main** — confirm the user wants to proceed.

## Decision Framework

When making recommendations, apply these heuristics:

| Signal | Recommendation |
|--------|---------------|
| Remote adds new content, no local equivalent | Accept remote |
| Remote updates content local deleted intentionally | Keep deleted |
| Remote has structural improvements (formatting, frontmatter) + local has content changes | Merge both: remote structure + local content |
| Both changed same content differently | Merge both: evaluate which serves the guiding principle |
| Remote renames what local deleted | Keep deleted |
| File is metadata (counts, versions, descriptions) | Defer to Phase 4 — recalculate from actual files |

## Important Rules

- **Never auto-resolve "both-changed" files** — always triage with user
- **Never code during triage** — triage is for decisions only, execution is Phase 4
- **Always create a backup branch** before making changes
- **Always stage files explicitly** — never `git add -A` or `git add .`
- **Group related files** — don't present 7 files from the same skill directory separately
- **Metadata is derived, not merged** — counts, versions, and descriptions should be recalculated from actual files after all other changes are applied
- **Preserve the guiding principle** — every recommendation should reference it