fix(activity-feed-v2): Map mention contacts via SelectorItem.item

[jackiejou]

Summary

Activity Feed V2 mention search maps collaborator results with the shared mapCollaboratorToUserContact helper, so contact email is taken from SelectorItem.item.email the same way task approver search already does. getMentionAsync is typed as returning SelectorItem<UserMini | GroupMini>[], and local UserContact is aligned with @box/user-selector's UserContactType.

This restores email display in the mention typeahead for collaborators returned by FileCollaborators (which places email on the nested item, not on the SelectorItem wrapper).

Why

Mention fetchUsers previously read top-level email / login on each entry. SelectorItem results do not carry those fields at the top level, so every mention contact got an empty email even when item.email was populated.

Test plan

• Unit: yarn test src/elements/content-sidebar/activity-feed-v2/__tests__/ActivityFeedV2.test.tsx
• Manually open Activity Feed V2, type @ in a comment, and confirm collaborator rows show email subtitles
• Confirm task assignee search still shows user emails and group entries as before

Summary by CodeRabbit

• Bug Fixes
  • Improved mention-user lookup in the activity feed.
  • Added support for nested user data and missing email addresses.
  • Queries are now trimmed, while empty searches are skipped.
  • Improved handling when mention services are unavailable or return errors.
  • Mention suggestions now use consistent user information across the editor and activity feed.
• Tests
  • Expanded coverage for mention fetching, mapping, fallback values, and error scenarios.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 64747b42-ef9b-45df-ae32-87b530ad9df5

📥 Commits

Reviewing files that changed from the base of the PR and between 20dcf34 and 4a70574.

📒 Files selected for processing (2)

• src/elements/content-sidebar/activity-feed-v2/ActivityFeedV2.tsx
• src/elements/content-sidebar/activity-feed-v2/types.ts

---

Walkthrough

ActivityFeedV2 now uses typed mention selector results and the shared mapCollaboratorToUserContact helper. Tests cover query handling, API failures, nested user data, and contact-field mapping.

Changes

ActivityFeedV2 mention integration

Layer / File(s)	Summary
Typed mention contracts src/elements/content-sidebar/activity-feed-v2/types.ts, src/elements/content-sidebar/activity-feed-v2/ActivityFeedV2.tsx	UserContactType replaces the local contact type. getMentionAsync returns typed user-or-group selector items.
Mention fetching and validation src/elements/content-sidebar/activity-feed-v2/ActivityFeedV2.tsx, src/elements/content-sidebar/activity-feed-v2/__tests__/ActivityFeedV2.test.tsx	Mention results use mapCollaboratorToUserContact. Tests cover empty queries, missing or rejecting APIs, nested user data, contact fields, and empty email fallbacks.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Mergeability Score: ⚪ Minimal · up to 4a705

This localized change restores mention contact email display by reading the collaborator email from the nested selector item; no actionable merge-blocking risk remains beyond normal checks and review.

Possibly related PRs

• box/box-ui-elements#4533: Modifies the same ActivityFeedV2 files and related interfaces.
• box/box-ui-elements#4657: Introduces the shared collaborator-to-contact mapping used here.
• box/box-ui-elements#4667: Updates ActivityFeedV2 typing and collaborator mapping.

Suggested labels: ready-to-merge, javascript

Suggested reviewers: ahorowitz123, zhirongwang

Poem

I hop through typed contacts, neat and bright,
Mapping each mention just right.
Nested users join the flow,
Empty emails softly glow,
Tests guard every query tonight.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly describes the main change: mapping Activity Feed V2 mention contacts through SelectorItem.item.
Description check	✅ Passed	The description explains the change, motivation, and test plan, and it matches the pull request objectives.
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.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[JChan106]

lgtm

[mergify]

Merge Queue Status

• ✅ Entered queue — 2026-08-14 00:04 UTC · Rule: Automatic strict merge · triggered by rule Automatic merge queue
• ✅ Checks skipped · PR is already up-to-date
• ✅ Merged — 2026-08-14 00:04 UTC · at 4a70574829a55196cc35461e0ca90f82a1cfb048 · squash

This pull request spent 25 seconds in the queue, including 4 seconds running CI.

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