badlogic/pi-skills

Overview

This skill integrates with Visual Studio Code to open side-by-side diffs and compare files. It leverages the VS Code command-line tool to present visual comparisons and can extract historic file versions from Git when needed. Use it when you need a quick, visual way to inspect changes between file revisions or separate files.

How this skill works

The skill calls the VS Code CLI (code -d fileA fileB) to open a two-pane diff of the provided paths. For Git-based comparisons, it extracts an older or staged version to a temporary file (using git show) and then launches a diff between the temp file and the working copy. It requires the 'code' command to be available in PATH and the target files to exist and differ.

When to use it

• Show a visual side-by-side diff of two files quickly.
• Review what changed between a commit and the working tree.
• Compare a staged version against the working copy before commit.
• Inspect differences during code review or debugging.
• Demonstrate edits to non-Git-controlled files.

Best practices

• Ensure VS Code is installed and the 'code' CLI is in PATH before calling the skill.
• Verify the file has history with git log --oneline -5 -- path/to/file before extracting old revisions.
• Use temporary files for Git extractions (e.g., /tmp/old) and clean them up when done.
• Confirm both paths exist and are different to avoid opening empty or identical diffs.
• Prefer specific commit hashes for reproducible comparisons rather than relative refs when possible.

Example use cases

• Compare the current file with the previous commit: git show HEAD~1:path/to/file > /tmp/old && code -d /tmp/old path/to/file
• Review staged changes vs working tree before committing.
• Compare two unrelated files on disk to inspect functional differences.
• Show a code reviewer the exact changes introduced by a patch.
• Diagnose regressions by comparing a known-good commit to the current source.