With enable_devtools_protection on, every click on the gallery failed and
trivial script evaluation hung -- confirmed on two independent events. A
guest with DevTools open for an unrelated reason (network tab, a CDP-attaching
extension) got a silently unresponsive gallery with no error shown.
Mechanisms found, all in the hook (both callsites were innocent):
1. detectByDebugger ran a bare `debugger;` on every tick at medium/high
sensitivity -- and the per-event flag maps to medium. With any debugger or
CDP client attached the renderer paused there continuously. This is why
Runtime.evaluate hung on 1+1 and clicks reported their target gone.
2. Four separate detectors called console.clear() -- the observed clear loop.
3. handleDevToolsDetected was useCallback([options]) over a fresh object
literal, so runDetection changed identity every render and the effect tore
down, rebound and re-ran detection on every render -- a 1s interval turned
into a tight loop.
4. detectByConsole monkey-patched console.log/error/warn/info every tick
inside a try/catch that swallowed throws, so a throw between patch and
restore left the guest's console permanently hijacked.
5. contextmenu was preventDefault'd document-wide regardless of target,
killing the menu on text, links and form fields -- disable_right_click is
the separate setting meant to cover the whole page.
Kept: the DevTools shortcut keys (only those exact combos; everything else
passes through), the docked-DevTools viewport heuristic as a pure measurement
on resize plus one check at mount, right-click blocked on IMG/CANVAS/VIDEO
targets only. The public API (onDevToolsDetected, redirectOnDetection,
redirectUrl, isDetected, reset) is unchanged, so PhotoLightbox needed no edit.
Removed: debugger traps, console.clear, console monkey-patching, the
timing/element/toString probes, the polling interval, document-wide
contextmenu blocking. Undocked DevTools is now deliberately undetectable --
every technique that catches it costs the page its responsiveness for
everyone. This is a deterrent, not a security boundary.
Also raised the viewport threshold (100 -> 160/200/260 by sensitivity):
browser chrome with a bookmarks bar is ~140px, so the old check false-positived
on ordinary windows, which at protectionLevel 'maximum' redirected legitimate
guests off the gallery.
Refs testplan REPORT.md #3 (Part 4).
Paul Nothaft
9d4bd7ab30