Cart Issues

Cart Issues & Cart Transform - Summary & Checklist

1. Cart Transform Not Merging Items

Symptoms: Bundle items show as separate lines instead of a single grouped bundle.

Check:

• Bundle edit page → enableCartTransform is ON
• Shopify admin → Settings → Apps → Cart Transform function is installed/registered
• Cart line has bundleSelections attribute

Fix:

1. Enable Cart Transform on the bundle.
2. If the function is missing, deactivate/reactivate the bundle or run bulk recovery from Settings → Advanced.
3. Ask the customer to remove and re-add the bundle so the cart line gets fresh attributes.

2. Parent Variant ID Missing

Symptoms: Bundle can’t be added as a single expandable line when Cart Transform is enabled.

Fix:

1. Open the bundle in the app.
2. Go to Cart Transform settings.
3. Set Parent Variant to a valid Shopify product variant.
4. That variant becomes the placeholder parent line that expands into child items.

3. Price Mismatches

Symptoms: Cart total doesn’t match the bundle widget price.

Common causes:

• presentmentCurrencyRate missing/incorrect.
• Rounding differences between widget and Shopify cart.
• extrasTotal (manual extras) not distributed correctly across child items.

Fix:

1. Ensure market-aware pricing is enabled in Settings.
2. Confirm the Storefront API token is valid (needed for currency data).
3. If using manual extras, verify extrasTotal equals the expected extra amount and is applied correctly.

4. Checksum Validation Failures

Each bundle line has an HMAC checksum to ensure the configuration wasn’t tampered with. If validation fails, the discount function ignores that line.

Common causes:

• Bundle configuration changed after items were added to cart.
• Another app or theme code modified cart line attributes.
• Invalid checksum format (not a 40+ character hex string).