ENG-3440: Fix TypeError when closing Data Catalog drawer

[gilluminate]

Ticket ENG-3440

Description Of Changes

Fixes a TypeError: Cannot read properties of undefined (reading 'privacy_declarations') that occurs when closing the Data Catalog drawer. The crash happened because system.privacy_declarations was accessed directly without a null check in the onClick handler, while the dataUses derivation already used optional chaining.

The fix extracts privacy_declarations into a safe declarations variable with a ?? [] fallback, then uses that reference consistently for both the data use list and the click handler.

Code Changes

• Extract system.privacy_declarations ?? [] into a declarations constant in EditDataUseCell.tsx
• Replace direct system.privacy_declarations[idx] access with safe declarations[idx] in the Tag onClick handler

Steps to Confirm

1. Enable the Data Catalog Beta flag
2. Navigate to the Data Catalog systems view
3. Click a system's vertical 3-dot menu and select "View details" to open the drawer
4. Close the drawer - confirm no TypeError is thrown
5. Open a system that has privacy declarations and verify data uses still display and are editable

Pre-Merge Checklist

• Issue requirements met
• All CI pipelines succeeded
• CHANGELOG.md updated
  • Add a db-migration This indicates that a change includes a database migration label to the entry if your change includes a DB migration
  • Add a high-risk This issue suggests changes that have a high-probability of breaking existing code label to the entry if your change includes a high-risk change (i.e. potential for performance impact or unexpected regression) that should be flagged
  • Updates unreleased work already in Changelog, no new entry necessary
• UX feedback:
  • All UX related changes have been reviewed by a designer
  • No UX review needed
• Followup issues:
  • Followup issues created
  • No followup issues
• Database migrations:
  • Ensure that your downrev is up to date with the latest revision on main
  • Ensure that your downgrade() migration is correct and works
    • If a downgrade migration is not possible for this change, please call this out in the PR description!
  • No migrations
• Documentation:
  • Documentation complete, PR opened in fidesdocs
  • Documentation issue created in fidesdocs
  • If there are any new client scopes created as part of the pull request, remember to update public-facing documentation that references our scope registry
  • No documentation updates required

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
fides-plus-nightly	Ready	Preview, Comment	Apr 15, 2026 5:00pm

1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
fides-privacy-center	Ignored		Apr 15, 2026 5:00pm

[github-actions]

Title	Lines	Statements	Branches	Functions
admin-ui		6.1% (2663/43631)	5.22% (1293/24738)	4.19% (542/12913)
fides-js		78.98% (1962/2484)	65.55% (1214/1852)	72.57% (336/463)
privacy-center		85.97% (331/385)	81.36% (179/220)	78.87% (56/71)

[claude]

Code Review: Fix TypeError in Data Catalog Drawer

This is a small, focused bug fix — no concerns. Summary below.

What the fix does

The root cause was an inconsistency in how privacy_declarations was accessed within the same component:

• dataUses was derived with system.privacy_declarations?.map(...) ?? [] (null-safe)
• The onClick handler referenced system.privacy_declarations[idx] directly (not null-safe)

If privacy_declarations were undefined at render time the dataUses map would produce no tags, but if the value transitioned to undefined after an initial render (e.g. after a delete mutation settled), the click handler could be called while system.privacy_declarations was momentarily undefined, throwing the TypeError described in the changelog.

Fix quality

The fix is minimal and correct:

1. Declares const declarations = system.privacy_declarations ?? []; once — always an array.
2. Derives dataUses from declarations (no more optional chaining needed).
3. Replaces system.privacy_declarations[idx] in the onClick handler with declarations[idx].

This removes the inconsistency, guarantees both usages share the same null-coalesced value, and is consistent with the TypeScript type (PrivacyDeclarationResponse[]).

Changelog

Entry is present and correctly formatted.

Verdict

✅ LGTM — no blocking issues.

---

🔬 Codegraph: unavailable

---

💡 Write /code-review in a comment to re-run this review.

[lucanovera]

Nice catch on this bug. Unfortunately, it looks like it's still failing when I close the drawer.

[lucanovera]

Confirmed the bug is fixed now. Approved!