Fix missing form names in Google Analytics

[DavidBiddle]

What problem does this pull request solve?

Trello card: https://trello.com/c/b6jmnphx/2288-track-branching-validation-errors

Our code for tracking validation errors in Google Analytics was returning null for the form name in many cases.

This is because the analytics logic was getting the form name from the input if it had form as an attribute, but some input objects - mainly those that change the page model - don't have the form attribute as they operate on draft_question instead.

This PR:

• adds a method to the draft question so it can get the name of its parent form
• uses the new method to populate the form_name field in the analytics for any input object that uses draft_question
• updates Pages::RoutingPageInput to use a form attribute so it can be read by the analytics.

Testing instructions

• Set analytics_enabled: true in your local settings (this isn't set in the review environment)
• log in as any non-super admin user
• go to any page with form fields within the form scope
• cause a validation error
• open the JS console and enter dataLayer
• You should see an event in there that looks something like this, including the name of the form:

{
  "event": "event_data",
  "event_data": {
    "event_name": "validation_error",
    "input_object_name": "Pages::TypeOfAnswerInput",
    "form_name": "Apply for a juggling licence",
    "error_field": "answer_type",
    "error_type": "blank"
  },
  "gtm.uniqueEventId": 5
}

Things to consider when reviewing

• Ensure that you consider the wider context.
• Does it work when run on your machine?
• Is it clear what the code is doing?
• Do the commit messages explain why the changes were made?
• Are there all the unit tests needed?
• Do the end to end tests need updating before these changes will pass?
• Has all relevant documentation been updated?

[thomasiles]

This was fiddly!

It looks nicely structured with good commit messages 🏅

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

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