A GitHub Action that compares two Bill of Materials (BOM) CSV files and generates a diff report in CSV format.
Includes support for flexible column mapping using a YAML config, and sorts the output by quantity change priority.

✨ Features

✅ Detects part additions, removals, and quantity changes
🛠 Customizable column mapping (columns.yml)
🔃 Output sorted by adjusted_quantity (positives first, zeros last)
🧠 Ignores specified part number patterns (e.g., testpoints, fiducials)
🧩 Simple to integrate into GitHub Actions workflows

📦 Inputs

Name	Description	Required
`bom_old`	Path to the original BOM CSV file	✅
`bom_new`	Path to the updated BOM CSV file	✅
`column_file`	Path to the YAML file describing columns	✅
`out_file`	Path where diff CSV will be saved	✅

🧪 Example Workflow

name: BOM Diff

on:
  push:
    paths:
      - 'bom_test_old.csv'
      - 'bom_test_new.csv'
      - 'columns.yml'

jobs:
  compare:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Run BOM Diff Action
        uses: ./  # Use relative path or replace with repo slug
        with:
          bom_old: bom_test_old.csv
          bom_new: bom_test_new.csv
          column_file: columns.yml
          out_file: test_diff.csv

      - name: Print Diff Output
        run: cat test_diff.csv