Merge Prep — Pre-merge Analysis and Preparation

Analyze source branch vs target branch, detect conflicts, output analysis report with suggested commands. v1 is analysis-only — does not execute merge/commit/push.

When NOT to Use

Scenario	Use Instead
Commit code (not merge)	/smart-commit
Merge to main (production)	Manual PR flow
Just view diff	git diff <target>..<branch>
Rebase or squash	Manual operation

Input

/merge-prep <source-branch> [--target <branch>]

• <source-branch>: Branch to merge (required)
• --target: Target branch (default: {TARGET_BRANCH} or main)

Workflow

sequenceDiagram
    participant C as Claude
    participant U as User
    C->>C: Step 1: Validate prerequisites
    C->>C: Step 2: Pre-merge analysis
    C->>U: Show analysis report
    U->>C: Acknowledge
    C->>C: Step 3: Conflict analysis (if any)
    C->>U: Show conflict details + resolution suggestions
    C->>C: Step 4: Generate merge commands
    C->>U: Output commands for manual execution

Step 1: Validate Prerequisites

# 1a. Verify source branch exists
git rev-parse --verify <branch>

# 1b. Verify target branch exists
git rev-parse --verify <target>

# 1c. Verify working tree is clean
git status --porcelain

Check	Failure Action
Branch doesn't exist	Halt, list available branches
Target not found	Halt, suggest creating it
Uncommitted changes	Halt, suggest /smart-commit first

Step 2: Pre-merge Analysis

Run the analysis script:

bash skills/merge-prep/scripts/pre-merge-check.sh <branch> [target]

Script outputs JSON containing:

• merge_base: Common ancestor
• source_commits: New commits on source branch
• target_commits: Commits on target that source doesn't have
• has_conflicts: Whether conflicts exist
• conflict_files: List of conflict files
• file_stats: Affected file statistics

Display analysis report:

## Pre-merge Analysis

| Item | Value |
|------|-------|
| Source branch | feat/new-feature |
| Target branch | main |
| Common ancestor | b03ad72a |
| New commits | 12 |
| Affected files | 46 |
| Predicted conflicts | 9 files |

### Recent Commits

| Hash | Message |
|------|---------|
| abc1234 | feat: Add new API endpoint |
| def5678 | test: Add integration tests |

Step 3: Conflict Analysis (if conflicts detected)

For each conflict file, analyze commit history to determine conflict pattern:

Pattern	Detection	Suggested Strategy
Iterative (v1→v3)	Both sides changed, source is superset	Take source
Parallel modification	Different people changed different logic	Per-hunk selection
Hotfix conflict	Target has hotfix merge, source doesn't	Take target
Doc add/add	Both sides added same-name file	Take source

Display resolution suggestions:

### Conflict Files

| # | File | Pattern | Suggestion | Reason |
|---|------|---------|------------|--------|
| 1 | src/xxx.ts | Iterative | Take source | v3 includes all v1 changes |
| 2 | src/yyy.ts | Parallel | Per-hunk | Two sides changed different functions |
| 3 | docs/zzz.md | add/add | Take source | Target version is outdated |

Step 4: Generate Merge Commands

Output commands for manual execution:

## Suggested Merge Commands

### Option A: Merge commit (recommended)

```bash
git checkout <target>
git pull --ff-only origin <target>
git merge <source> --no-ff
# Resolve conflicts if any
# git add <resolved-files>
# git commit
git push origin <target>

Option B: Squash merge

git checkout <target>
git pull --ff-only origin <target>
git merge --squash <source>
git commit -m "merge: Merge <source> into <target>"
git push origin <target>

### Step 5: Summary

```markdown
## Merge Summary

| Item | Value |
|------|-------|
| Source | feat/new-feature |
| Target | main |
| Commits | 12 |
| Files | 46 |
| Conflicts | 9 (resolution suggestions provided) |
| Tickets | PROJ-520, PROJ-123 |

⚠️ This is an analysis-only report. Execute the commands manually.

Multi-branch Mode

Supports /merge-prep branch1 branch2 branch3 --target develop:

1. Analyze each branch sequentially
2. Output combined summary
3. Suggest merge order (fewest conflicts first)

Prohibited (v1)

• No auto-merge: Only output commands, never execute git merge
• No auto-push: Never execute git push
• No auto-commit: Never execute git commit
• No rebase: Never suggest or execute rebase operations

References

File	Purpose	When to Read
pre-merge-check.sh	Pre-merge analysis script	Step 2

Verification

• Source branch exists and working tree is clean
• Pre-merge analysis displayed with user acknowledgment
• Conflicts analyzed with resolution suggestions
• Merge commands are output-only (not executed)
• No secrets in output, no force push suggested