🐛 Fixed staff invite error for existing users

[aileen]

closes https://linear.app/ghost/issue/ONC-1778

Summary

• Maps the invite API duplicate-user validation error back to the email field in the staff invite modal
• Keeps pagination behavior intact while avoiding the generic failure toast for existing staff users
• Adds an acceptance test for an existing user outside the loaded first users page

Testing

• NODE_PATH=/Users/aileen/code/tryghost/Ghost/node_modules/.pnpm/node_modules pnpm --filter @tryghost/admin-x-settings test:acceptance test/acceptance/general/users/invite.test.ts --project=chromium
• NODE_PATH=/Users/aileen/code/tryghost/Ghost/node_modules/.pnpm/node_modules pnpm --filter @tryghost/admin-x-settings lint:js

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📥 Commits

Reviewing files that changed from the base of the PR and between 81e2cea and 1ce6687.

📒 Files selected for processing (4)

• apps/admin-x-settings/src/components/settings/general/invite-user-modal.tsx
• apps/admin-x-settings/test/acceptance/general/users/invite.test.ts
• ghost/core/core/server/api/endpoints/utils/validators/input/invites.js
• ghost/core/test/e2e-api/admin/invites.test.js

🚧 Files skipped from review as they are similar to previous changes (1)

• apps/admin-x-settings/src/components/settings/general/invite-user-modal.tsx

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Walkthrough

This PR refines the invite-user modal to provide clearer error feedback when users attempt to invite existing users. It imports ValidationError, defines two error message constants, and adds special-case handling in the error catch block: if a ValidationError contains the "User is already registered." message, the component clears save state and sets the email field error to "A user with that email address already exists." instead of showing a generic API failure toast. A new acceptance test verifies this behavior by mocking a 422 validation response for an existing user email and confirming field-level validation text appears without a visible error toast.

Suggested reviewers

• sam-lord
• mike182uk

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly describes the main change: fixing a staff invite error for existing users, which aligns with the core objective of mapping the duplicate-user validation error.
Description check	✅ Passed	The description is directly related to the changeset, outlining how the invite API validation error is mapped to the email field, pagination behavior is preserved, and includes a test case reference.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[sagzy]

nit: unnecessary constant / abstraction, could inline it

if (validationError?.code === 'USER_ALREADY_REGISTERED') { ... } 

[aileen]

Agree to disagree here. I would class this as a classical magic string which I'd probably tidy up going through the code later on 😄 I guess that's more about personal preference in this case 😅

[sagzy]

Yeh definitely taste-based!

Personally, I go for:

• Abstract in a constant if used in multiple places (benefit: if updated, need to update a single place)
• Keep it inline if used in a single place (still have the same benefit of updating a single place, but don't create the overhead of an abstraction, i.e. having to jump to another piece of code when reading)