Retrieve Diff From Commit

Retrieve Diff from Commit Skill

An input skill that retrieves code diff from local git commits. This is the entry point for reviewing local changes before they are pushed.

Role

• Extract: Get the diff content from a specific commit or range of commits
• Format: Prepare the diff in a format suitable for code review
• Context: Gather commit metadata (author, message, timestamp)

Inputs

Outputs

Usage

Review Single Commit

# Get diff for specific commit
git show <commit_sha> --format="%H%n%an%n%ae%n%s%n%b" --stat

# Get unified diff
git diff <commit_sha>^..<commit_sha>

Review Commit Range

# Get diff for range
git diff <base_commit>..<head_commit>

# Get list of commits in range
git log --oneline <base_commit>..<head_commit>

Review Branch Against Base

# Compare feature branch to main
git diff main...HEAD

# Get merge-base
git merge-base main HEAD

Step 1: Identify the Scope

Determine what to review:

Step 2: Extract Diff

Execute the appropriate git command:

# For comprehensive diff with context
git diff --unified=5 <base>..<head>

# Include file stats
git diff --stat <base>..<head>

# Get list of changed files
git diff --name-status <base>..<head>

Step 3: Gather Metadata

Collect commit information:

# Get commit details
git log --format="%H|%an|%ae|%at|%s" <base>..<head>

# Get file change summary
git diff --shortstat <base>..<head>

Step 4: Format Output

Structure the output for the review pipeline:

## Diff Retrieved

**Commit Range**: `<base>..<head>`
**Files Changed**: X
**Lines Added**: +Y
**Lines Deleted**: -Z

### Files

| Status | File |
|--------|------|
| M | src/auth/login.ts |
| A | src/utils/helper.ts |
| D | src/deprecated.ts |

### Diff Content

\`\`\`diff
<unified diff content>
\`\`\`

### Commit Info

| Field | Value |
|-------|-------|
| SHA | abc123... |
| Author | John Doe <john@example.com> |
| Date | 2024-01-15 10:30:00 |
| Message | feat: add login functionality |

Output Format

{
  "source": "local-git",
  "commit_range": {
    "base": "<base_sha>",
    "head": "<head_sha>"
  },
  "stats": {
    "files_changed": 5,
    "insertions": 120,
    "deletions": 45
  },
  "files": [
    {
      "path": "src/auth/login.ts",
      "status": "modified",
      "additions": 50,
      "deletions": 10
    }
  ],
  "commits": [
    {
      "sha": "abc123",
      "author": "John Doe",
      "email": "john@example.com",
      "timestamp": "2024-01-15T10:30:00Z",
      "message": "feat: add login functionality"
    }
  ],
  "diff": "<unified diff content>"
}

Integration with Review Pipeline

After retrieving the diff, pass the output to:

1. codereview-orchestrator - For triage and routing
2. Then to appropriate specialist skills based on the triage

Quick Reference

□ Identify Scope
  □ Single commit, range, or branch?
  □ Committed or uncommitted?

□ Extract Diff
  □ Run appropriate git diff command
  □ Include sufficient context (--unified=5)

□ Gather Metadata
  □ Commit info (SHA, author, message)
  □ File statistics

□ Format Output
  □ Structure for review pipeline
  □ Include all necessary context

Example Usage in Pipeline

1. retrieve-diff-from-commit (this skill)
   ↓
2. codereview-orchestrator (triage)
   ↓
3. Specialist skills (review)
   ↓
4. Output formatted findings

Converted and distributed by TomeVault — claim your Tome and manage your conversions.