App proxy doesn't work with multiple query parameters

[jonmast]

Issue summary

Before opening this issue, I have:

• Upgraded to the latest version of the relevant packages
  • @shopify/* package and version:
  • Node version:
  • Operating system:
• Set { logger: { level: LogSeverity.Debug } } in my configuration, when applicable
• Found a reliable way to reproduce the problem that indicates it's a problem with the package
• Looked for similar issues in this repository
• Checked that this isn't an issue with a Shopify API
  • If it is, please create a post in the Shopify community forums or report it to Shopify Partner Support

When authenticating an app proxy request, hmac validation fails if a query parameter is repeated.

Expected behavior

HMAC signature validation should still pass

Actual behavior

It fails

Steps to reproduce the problem

1. Create an app proxy route
2. Call it with a repeated query param ie a=1&a=2
3. It will fail with an auth error

[github-actions]

We're labeling this issue as stale because there hasn't been any activity on it for 60 days. While the issue will stay open and we hope to resolve it, this helps us prioritize community requests.

You can add a comment to remove the label if it's still relevant, and we can re-evaluate it.