Lindat/Search console error on view-mode switch: drop data-toggle=buttons (Bootstrap null-deref)

[Kasinhou]

One of the fan-out PRs for the /search console-error fix (see the blast-radius table below). The ZCU PRs (#1482, #1483) merged and the Playwright consoleErrors test on /search went green, confirming the fix.

Problem

The Playwright consoleErrors.spec.ts → "page 'search…' should not have console errors" fails on /search with an uncaught pageerror (Firefox consistently; all engines intermittently, as a hydration race):

• Firefox: can't access property "checked", s is null
• Chromium: Cannot read properties of null (reading 'checked')
• WebKit: null is not an object (evaluating 's.checked')

Fixes dataquest-dev/dspace-customers#931

Root cause

The theme bundles Bootstrap 4.6.1 JS (angular.json scripts → node_modules/bootstrap/dist/js/bootstrap.bundle.min.js) plus jQuery 2.1.4 (src/index.html). On window.load, Bootstrap's load.bs.button.data-api handler iterates [data-toggle="buttons"] .btn and reads .checked on querySelector('input:not([type="hidden"])').

The search view-mode switch renders <div class="btn-group" data-toggle="buttons"> with routerLink children and no <input>, so querySelector returns null and .checked throws. The inputless buttons only exist after Angular hydration, so whether the crash fires depends on a window.load-vs-hydration race — hence the Firefox-only / flaky appearance.

Change set

Remove the data-toggle="buttons" attribute from src/app/shared/view-mode-switch/view-mode-switch.component.html — the minimal change that removes the element the handler chokes on. The attribute is semantically wrong here (there are no toggle <input>s) and inert in stock ng-bootstrap DSpace; routerLinkActive="active" + [class.active] already drive the active state, so the list/grid/detail toggle is unchanged visually and functionally.

Scope note (core vs theme): the markup is in DSpace core, but ViewModeSwitchComponent is not themeable (no ThemedViewModeSwitchComponent), so a ThemedComponent override would require adding a wrapper to core — a larger core change. Removing the inert attribute is provably safe for every customer (0 .scss/.css rules target [data-toggle="buttons"]; no spec asserts it). Not chosen: dropping Bootstrap JS from angular.json (the issue's "Alternative" — broader blast radius).

Blast radius (why this branch is included)

The crash needs all three at once: the attribute present + Bootstrap 4 JS bundled + jQuery loaded.

Customer	Version	Bootstrap	BS-JS + jQuery	Status
ZCU-PUB / ZCU-DATA	7.6.1	4.6.1	yes	✅ fixed & merged (#1482 / #1483)
TUL	7.5	4.6.1	yes	this fan-out
VSB-TUO	7.6.5	4.6.1	yes	this fan-out
dtq-dev / UFAL	7.6.5	4.6.1	yes	this fan-out
SAV	7.6.1	4.6.1	yes	intentionally deferred (owner's call)
MENDELU / JCU	9.1 / 9.3	5.3	no	not affected (BS5 dropped the plugin)

Test evidence

git grep 'data-toggle="buttons"' -- src/        -> 0 after change (was 1, only this file)
grep '[data-toggle="buttons"]' **/*.{scss,css}  -> 0 (no styling depends on it)
view-mode-switch.component.spec.ts              -> no assertion on the attribute

Local full CI (yarn lint / check-circ-deps / build:prod / test:headless) was not run here: the 7.x branches use the Yarn 1.x + Node 16/18 toolchain and this box is on Node 22 (documented incompatibility). Authoritative gates: this branch's CI + the Playwright consoleErrors test on /search — already confirmed green on the equivalent ZCU fix.

[Copilot]

Pull request overview

This PR removes the data-toggle="buttons" attribute from the /search view-mode switch markup to prevent Bootstrap 4’s button data-api from null-dereferencing a missing <input> during window.load, eliminating the flaky/Firefox console error caused by the hydration timing race.

Changes:

• Drop data-toggle="buttons" from the view-mode switch .btn-group container.
• Preserve existing active-state behavior via routerLinkActive="active" and [class.active] (no functional change intended).

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