deckhearth/.convoys/cleanup-mobile-nav-dead-props.md

cleanup-mobile-nav-dead-props (P3 polish — single-prop hygiene)

Status: SHIPPED 2026-05-26 (PR TBD) Classification: hygiene Priority: P3 polish (not a bug, not a security issue; dead-prop removal is purely a clarity-of-surface cleanup) Convoy owner: parent (no architect — single-line prop removal in one component + one caller; surfaced and pre-decided in a sibling convoy) Opened: 2026-05-26

Background

components/MobileNavigation.js accepts { user, onMenuOpen } but never reads user.* — the bottom-bar items (Cards, Decks, Dashboard, Community, More) are static and don't depend on auth state or role.

This was originally surfaced as R8 in the fix-layout-default-user convoy (see .convoys/fix-layout-default-user.md § R8 and § "Anything flagged but not acted on") and deferred there with explicit instructions: "If the implementer is tempted to delete the prop, they MUST stop — that's god-component-split / single-auth-provider territory." The deferral was correct for that convoy's scope; it is no longer needed because the prop is genuinely dead at the current static-bar reality, and removing it does not require a wider auth refactor.

The follow-up was queued as cleanup-mobile-nav-dead-props in .convoys/ship-readiness.md § Queued convoys, with a note that it may fold into god-component-split (P2 #13) if that lands first. God-component-split has not landed; this small hygiene convoy ships first.

Audit results

Pre-edit audit (the spec's "don't blindly trust the queue entry" clause):

1. Reading components/MobileNavigation.js — the file is 171 lines. Line 5 destructures { user, onMenuOpen }. Lines 6–170 use onMenuOpen exactly once (line 39, as the onClick for the "More" button). user does not appear elsewhere — no user.email, user.role, user.id, no conditional render gated on user, no pass-through to a child component. The bottom-bar navigationItems array is hardcoded and does not branch on auth state.
2. rg '\buser\b' components/MobileNavigation.js before edit: 1 hit (the destructure on line 5). After edit: 0 hits.
3. rg "MobileNavigation" components/ pages/ --type js: two import + JSX-callsite pairs in the codebase:
   • components/Layout.js (active) — line 5 import, line 598-601 JSX call passing user={user} and onMenuOpen={...}.
   • components/Layout.js.backup (no-go-zone per .cursor/rules/no-go-zones.mdc § "Append-only / historical" — "legacy snapshot; delete with a real PR, never edit") — line 5 import, line 264 JSX call. Left untouched per the no-go-zone rule; if/when the .backup file is eventually deleted, this dead call disappears with it.

Audit verdict: user is genuinely dead. Cleanup is safe.

The fix

Two-file, three-line diff:

1. components/MobileNavigation.js line 5: remove user from the destructured props.
   • Before: export default function MobileNavigation({ user, onMenuOpen }) {
   • After: export default function MobileNavigation({ onMenuOpen }) {
2. components/Layout.js lines 598-601: remove the user={user} JSX attribute from the only active call site.
   • Before:

     <MobileNavigation
       user={user}
       onMenuOpen={() => setIsMobileMenuOpen(true)}
     />
     

   • After:

     <MobileNavigation
       onMenuOpen={() => setIsMobileMenuOpen(true)}
     />
     

No new code. No refactors. No tests added (the component has no direct test coverage; test/components/Layout.test.js tests Layout's logged-out branch and does not assert on MobileNavigation's prop shape).

Out of scope

• The unused import { useState } from 'react' on components/MobileNavigation.js line 3. The hook is imported but not called. This is a pre-existing dead import unrelated to the user prop; the convoy spec explicitly forbids "refactor anything else in MobileNavigation.js (this is a single-prop removal)". A future hygiene pass can sweep it (or it'll get caught by an eventual lint-no-unused-imports rule).
• components/Layout.js.backup — no-go-zone, untouched.

Verification plan

1. rg '\buser\b' components/MobileNavigation.js → 0 hits (post-edit confirmation that the prop is truly gone, not just renamed).
2. rg "MobileNavigation" components/ pages/ --type js → confirm each active call site passes only onMenuOpen.
3. npm run lint → 128 problems baseline preserved (no regression introduced; no new dead-code/unused-var warnings created by the change).
4. npm run test:run → 21/21 pass. Specifically, test/components/Layout.test.js continues to pass — its regression-lock assertions for the logged-out Layout branch (Gotcha #8) do not depend on MobileNavigation's prop shape, so the dead-prop removal is invisible to that suite.
5. npm run build skipped — relying on Vercel preview CI. Trade-off: single-prop removal in a leaf component is extremely low risk of build-time regression, and the Playwright smoke + visual-diff workflows on the PR will catch any Layout-rendering issue before merge.

Risks

• R1 — A future feature that wants per-user bottom-bar items would need to re-add the prop. Hypothetical examples: showing an unread-count badge on a "Notifications" tab gated on user.id, or hiding the "Community" tab for unauthenticated visitors. Accepted. Re-adding a prop is a one-line change when the feature actually lands; carrying a dead prop "just in case" obscures the current surface and adds nothing. The cleanup is correct for the current static-bar reality; future features pay their own add-the-prop cost.
• R2 — components/Layout.js.backup still references the old prop shape. Accepted. The backup is a no-go-zone (per .cursor/rules/no-go-zones.mdc) and is dead code by definition. Touching it would violate the rule; leaving it as a stale snapshot is the convention. When the backup is eventually deleted in a separate convoy, this stale call disappears with it.

Acceptance criteria

• 2 files modified, 3 lines net change (1 line edit + 1 attribute removal from a multi-line JSX block).
• npm run lint exit 1 with 128 problems (baseline preserved).
• npm run test:run 21/21 pass.
• rg '\buser\b' components/MobileNavigation.js → 0 hits post-edit.

Owns

Parent (single-prop removal in a leaf component; no architect or implementer subagent required; audit confirms the queue entry's premise).

As-shipped

Single squash commit 171f5af (PR #28, merged 2026-05-27T03:53:29Z UTC / local 2026-05-26). Parent-owned end-to-end per the convoy spec — no architect, no implementer subagent dispatched. Single-prop removal in a leaf component, exactly as planned; no mid-execution surprises.

Diff: 3 files, +156 / -2. components/MobileNavigation.js (1 line edit — removed user from the destructured props) + components/Layout.js (1 attribute removal from the JSX call site — removed user={user}) + .convoys/cleanup-mobile-nav-dead-props.md (the planning document, committed atomically with the fix). The +156 addition figure is dominated by the planning doc; actual source diff is 3 lines net.

The two surface edits:

1. components/MobileNavigation.js line 5: export default function MobileNavigation({ user, onMenuOpen }) { → export default function MobileNavigation({ onMenuOpen }) {.
2. components/Layout.js lines 598-601: removed the user={user} JSX attribute from the only active <MobileNavigation> call site.

Audit verdict pre-fix confirmed. The pre-edit grep (rg '\buser\b' components/MobileNavigation.js) returned 1 hit (the destructure on line 5); post-edit grep returned 0 hits. The bottom-bar items (Cards, Decks, Dashboard, Community, More) are static and don't depend on auth state or role — the user prop was genuinely dead.

components/Layout.js.backup left untouched per the .cursor/rules/no-go-zones.mdc § "Append-only / historical" rule ("legacy snapshot; delete with a real PR, never edit"). The backup still references the old MobileNavigation({ user, onMenuOpen }) prop shape; when the .backup file is eventually deleted in a separate convoy, that stale call disappears with it. This is the documented out-of-scope handling.

Verification (all gates green at merge):

• rg '\buser\b' components/MobileNavigation.js → 0 hits post-edit
• rg "MobileNavigation" components/ pages/ --type js → 1 active call site (components/Layout.js) passing only onMenuOpen, plus the historical .backup reference (intentional)
• npm run lint → 125 problems (post-PR-#31 baseline preserved; no new dead-code/unused-var warnings created by the change)
• npm run test:run → 21/21 pass. Specifically, test/components/Layout.test.js's 5 regression-lock assertions for the logged-out Layout branch (Gotcha #8) continue to pass — they don't assert on MobileNavigation's prop shape, so the dead-prop removal is invisible to the suite
• CI on PR #28: Lint ✓ | Vitest 21/21 ✓ | Playwright smoke 3/3 ✓ | forbidden-endpoints ✓ | forbidden-cors-headers ✓ | Vercel preview deploy ✓ | Aggregate gate ✓
• Screenshot diff: triggered (PR #28 touches components/** which matches the visual-diff path filter) — continue-on-error: true swallow per the documented Decision-4 end state of adopt-playwright-smoke (no baseline committed yet). Not a regression; the dead-prop removal cannot move a single rendered pixel because the prop was never read.

Out-of-scope items preserved as documented:

• Pre-existing dead import { useState } from 'react' on components/MobileNavigation.js line 3 — untouched per the convoy spec's "single-prop removal" boundary. A future hygiene pass can sweep it.
• components/Layout.js.backup — untouched per no-go-zone rule.

Operator action required going forward: none. No env vars, no schema, no infra.

Spec deviation: none.

No follow-up surfaced. The convoy's documented R1 (hypothetical future feature that wants per-user bottom-bar items) is an "accept the cleanup, pay the add-the-prop cost when the feature actually lands" call — not a queued follow-up.