diff-summary

Diff Summary

Classify git diffs as formatting-only vs substantive changes. Useful for understanding what actually changed vs what was just reformatted.

Arguments

• $ARGUMENTS: Empty (working tree vs HEAD), --staged, or commit range (e.g., HEAD~3..HEAD).

Steps

Step 1: Get diffs

Run two diffs:

1. git diff --stat {range} — with whitespace
2. git diff -w --stat {range} — ignoring whitespace

If --staged: use git diff --cached instead.

Step 2: Compare

For each file:

• If it appears in both diffs with the same change count → SUBSTANTIVE
• If it appears only in the first diff (disappears when ignoring whitespace) → FORMATTING ONLY
• If it appears in both but with different counts → MIXED (some substantive, some formatting)

Step 3: Report

Diff Classification:

SUBSTANTIVE:
  src/parser.ts      | 42 ++++---
  src/types.ts       | 15 +++

FORMATTING ONLY:
  src/utils.ts       | 8 +++---
  src/config.ts      | 3 +--

MIXED:
  src/router.ts      | 25 +++--- (12 substantive, 13 formatting)

Summary: 2 substantive, 2 formatting-only, 1 mixed