Browser Extensions Cause "Cannot redefine property: Shopify" Error

[frankl1nrg]

What is the location of your example repository?

https://github.com/Shopify/hydrogen/tree/main/templates/skeleton

Which package or tool is having this issue?

Hydrogen

What version of that package or tool are you using?

2026.1.0

What version of Remix are you using?

7.12.0

Steps to Reproduce

1. Install Urban VPN browser extension (note that this is only one example, there could be more extensions)
2. Visit any Hydrogen store (e.g., https://skeleton.hydrogen.shop/)
3. Open browser developer console
4. Observe TypeError: Cannot redefine property: Shopify error
5. Notice the app crashes/becomes unusable (The Remix/RR error boundary kicks in)

Expected Behavior

1. Framework resilience: Hydrogen apps should not crash regardless of which browser extensions users have installed
2. Defensive coding: The logic in ShopifyCustomerPrivacy.tsx:344 should check if window.Shopify is already defined and handle both configurable and non-configurable scenarios gracefully
3. Consistent experience: Hydrogen should provide the same level of stability as Shopify Theme stores when dealing with third-party scripts
4. Graceful degradation: If an extension conflicts with Hydrogen's property definitions, the app should continue functioning with appropriate fallback behavior
5. User-first approach: End users shouldn't need to disable legitimate browser extensions to use Hydrogen stores

Actual Behavior

App becomes completely unusable with TypeError: Cannot redefine property: Shopify when browser extensions define the property as non-configurable.

Relevant resources

• Error: "Cannot redefine property: Shopify" when run Hydrogen on local #2549
• chrome-extension://eppiocemhmnlbhjplcgkofciiegomcon/libs/extend-native-history-api.js
• ChatGPT conversation: Ad-blockers and Website Breakage
• Loom video

[frankl1nrg]

I've started working on a fix for this issue: #3576

This should resolve crashes for users with Urban VPN and similar extensions while preserving all existing Hydrogen functionality.

[frankl1nrg]

Additional Context

Historical scope: I reproduced this on Hydrogen ^2025.1.0, so this predates the RR7 migration and has existed in earlier Remix v2 versions.

Impact: Likely low overall (most traffic is mobile, fewer extensions), but complete app failure for affected users.

Broader issue: Any injected script that mutates window.Shopify can crash the app - not just browser extensions. We've seen similar problems with:

• Apps originally designed for Themes mutating window.Shopify or making /cart/add.js (Cart AJAX endpoint) calls in headless context.
• Any client-side JS failure triggering error boundaries

TL;DR

• Remix / RR error boundaries are too aggressive - minor JS failures shouldn't crash entire apps.