diff --git a/static/js/session.js b/static/js/session.js index c984fc5..5d6daa2 100644 --- a/static/js/session.js +++ b/static/js/session.js @@ -146,6 +146,20 @@ export async function showScreen(id) { // Capture the previous screen before changing active classes const prevScreenId = document.querySelector('.screen.active')?.id; + + // ── screen:changing — emitted BEFORE any of the work below ────────────────── + // + // Timing matters here, and Codex caught me getting it wrong. The stems plugin used to + // monkey-patch window.showScreen so it could tear down its audio graph BEFORE navigation + // began. screen:changed fires at the very END of this function — after awaiting library and + // provider loads — so moving that plugin onto it would have delayed teardown behind a slow + // fetch, or skipped it entirely if the fetch threw. Stems would keep playing on a non-player + // screen. + // + // So there are two events, and the distinction is the whole point: + // screen:changing — before anything happens. "I am leaving `from`." Cancel/teardown here. + // screen:changed — after the DOM and data are settled. "I am on `id`." + if (window.feedBack) window.feedBack.emit('screen:changing', { id, from: prevScreenId || null }); document.querySelectorAll('.screen').forEach(s => s.classList.remove('active')); document.getElementById(id).classList.add('active'); // Mark the next render as a screen-entry so it scrolls the @@ -225,7 +239,15 @@ export async function showScreen(id) { setPlayButtonState(false); } window.scrollTo(0, 0); - if (window.feedBack) window.feedBack.emit('screen:changed', { id }); + // `from` is the screen we just LEFT. Without it, "I am leaving the player" is not + // expressible from an event, and the only way to express it was to WRAP window.showScreen — + // which is what shell.js and the stems plugin both did, and why the library intermittently + // showed the legacy screen (#923, #924): three parties patching one global, each capturing + // whatever was there at the time, in whatever order the plugin loads settled. + // + // Additive: every existing listener (app.js, audio-mixer.js, tour-engine.js) reads `id` and + // is unaffected. + if (window.feedBack) window.feedBack.emit('screen:changed', { id, from: prevScreenId || null }); } export let currentFilename = ''; diff --git a/static/v3/shell.js b/static/v3/shell.js index 0a935c1..a259084 100644 --- a/static/v3/shell.js +++ b/static/v3/shell.js @@ -318,22 +318,49 @@ } } - // ── showScreen wrapper (idempotent rehydration — design/05 §Rehydration) ─ + // ── Stay in sync with the active screen (idempotent rehydration — design/05) ─ + // + // This USED to monkey-patch window.showScreen. It doesn't any more, and that is the point. + // + // Three parties were wrapping that one global — app.js publishes it, this wrapped it, and the + // stems plugin wrapped it again — each capturing whatever happened to be there at the time. + // Plugins load ASYNCHRONOUSLY, so the chain linked up in whatever order the race settled, and + // a capture taken before this installed silently dropped the home -> v3-songs mapping this + // wrapper carried. That is why the library intermittently showed the legacy screen (#923). + // + // The mapping lives inside showScreen() now, where no wrapper can lose it. And everything + // left here is just "the screen changed" — which showScreen already EMITS, and which app.js, + // audio-mixer.js and tour-engine.js have always listened for rather than patching. + // + // So: be a listener, like everyone else. window.showScreen is a plain function again. function installShowScreenHook() { const hooks = window.__feedBackV3ShellHooks || (window.__feedBackV3ShellHooks = {}); - hooks.syncActive = syncActive; // always point at the latest impl + hooks.syncActive = syncActive; // always point at the latest impl if (hooks.installed) return; hooks.installed = true; - hooks.baseShowScreen = window.showScreen; - window.showScreen = function (id) { - // Route every "go to the library" navigation to the v3 native Songs - // screen instead of the legacy #home library, so player-close, - // settings-back, the hidden legacy navbar, etc. all stay in v3. - const target = (id === 'home') ? 'v3-songs' : id; - const r = hooks.baseShowScreen ? hooks.baseShowScreen.call(this, target) : undefined; - try { hooks.syncActive && hooks.syncActive(target); } catch (e) { /* non-fatal */ } - return r; + + // RETRY IF THE BUS IS LATE. The old wrapper didn't need window.feedBack to exist; a + // listener does. Bailing out when it isn't ready yet would silently leave the sidebar + // highlight and topbar title frozen forever — a dead nav, with nothing thrown. (Codex + // caught the identical hole in the stems plugin's version of this.) + const wire = () => { + const bus = window.feedBack; + if (!bus || typeof bus.on !== 'function') { + // `feedBack:capabilities:ready` — capabilities.js:1536. NOT the slopsmith: name: + // that was the pre-DMCA event and NOTHING dispatches it any more, so a fallback + // keyed on it can never fire. Codex caught exactly that here. (The old alias is + // kept too, in case an older capabilities build is in play.) + window.addEventListener('feedBack:capabilities:ready', wire, { once: true }); + window.addEventListener('slopsmith:capabilities:ready', wire, { once: true }); + return; + } + bus.on('screen:changed', (ev) => { + const id = ev && ev.detail && ev.detail.id; + if (!id) return; + try { hooks.syncActive && hooks.syncActive(id); } catch (e) { /* non-fatal */ } + }); }; + wire(); } // ── Boot ──────────────────────────────────────────────────────────────── diff --git a/tests/js/no_showscreen_monkeypatch.test.js b/tests/js/no_showscreen_monkeypatch.test.js new file mode 100644 index 0000000..97e81b9 --- /dev/null +++ b/tests/js/no_showscreen_monkeypatch.test.js @@ -0,0 +1,95 @@ +// Nobody may monkey-patch window.showScreen. (#924) +// +// It used to be wrapped by THREE independent parties, each capturing whatever happened to be +// there at the time: +// +// app.js publishes the raw function +// -> static/v3/shell.js wrapped it (to call syncActive, and to map home -> v3-songs) +// -> the stems plugin wrapped it AGAIN (to tear down on leaving the player) +// +// Plugins load ASYNCHRONOUSLY, so the chain linked up in whatever order the race settled. A +// capture taken before shell.js installed silently dropped the mapping it carried — and the +// library opened on the dead legacy #home screen. Testers saw that as "randomly, the library +// shows the old interface" (#923). +// +// Neither wrapper ever needed to be one. showScreen already EMITS screen:changed, and that is +// already how app.js, audio-mixer.js and tour-engine.js do it. Both are listeners now, and +// window.showScreen is a plain function again — so the ordering hazard is structurally +// impossible rather than merely avoided. +// +// This test is the thing that keeps it that way. A wrapper reintroduced anywhere in static/ +// fails CI. + +const { test } = require('node:test'); +const assert = require('node:assert/strict'); +const fs = require('node:fs'); +const path = require('node:path'); + +const ROOT = path.join(__dirname, '..', '..'); + +function jsFiles(dir) { + const out = []; + for (const e of fs.readdirSync(dir, { withFileTypes: true })) { + const p = path.join(dir, e.name); + if (e.isDirectory()) out.push(...jsFiles(p)); + else if (e.name.endsWith('.js')) out.push(p); + } + return out; +} + +// strip comments so the prose above (and in shell.js) isn't read as an assignment +const scrub = (s) => s.replace(/\/\*[\s\S]*?\*\//g, '').replace(/^\s*\/\/[^\n]*$/gm, ''); + +test('nothing in static/ assigns window.showScreen', () => { + const offenders = []; + for (const f of jsFiles(path.join(ROOT, 'static'))) { + const src = scrub(fs.readFileSync(f, 'utf8')); + // `window.showScreen = ...` — an assignment, not a call or a typeof guard + if (/window\.showScreen\s*=(?!=)/.test(src)) offenders.push(path.relative(ROOT, f)); + } + assert.deepEqual( + offenders, [], + 'these files monkey-patch window.showScreen. Do not: three wrappers racing over one ' + + 'global is what made the library open on the legacy screen (#923). Listen to ' + + 'screen:changed instead — showScreen already emits it, with { id, from }.', + ); +}); + +test('showScreen emits screen:changed with the screen it LEFT', () => { + const src = fs.readFileSync(path.join(ROOT, 'static', 'js', 'session.js'), 'utf8'); + assert.match( + src, + /emit\('screen:changed',\s*\{\s*id,\s*from:/, + "screen:changed must carry `from` — without it, \"I am leaving the player\" is not " + + 'expressible from an event, and the only way to say it is to wrap showScreen, which is ' + + 'the bug this exists to prevent', + ); +}); + +test('screen:changing fires BEFORE the navigation work, screen:changed after', () => { + // The distinction is the whole point, and Codex caught me collapsing it. + // + // The stems plugin's wrapper tore down its audio graph BEFORE showScreen did anything. + // screen:changed fires at the very END — after core awaits library and provider loads — so + // moving the plugin onto it would delay teardown behind a slow fetch, or skip it if that + // fetch threw, and stems would keep playing on a non-player screen. + // + // screen:changing before anything happens. "I am leaving `from`." Cancel/teardown here. + // screen:changed after the DOM and data settle. "I am on `id`." + const src = fs.readFileSync(path.join(ROOT, 'static', 'js', 'session.js'), 'utf8'); + const changing = src.indexOf("emit('screen:changing'"); + const changed = src.indexOf("emit('screen:changed'"); + assert.ok(changing !== -1, 'screen:changing must be emitted'); + assert.ok(changed !== -1, 'screen:changed must be emitted'); + assert.ok(changing < changed, 'screen:changing must come first'); + + // and `changing` must precede the first await, or it is no earlier than `changed` in practice + const firstAwait = src.indexOf('await ', changing); + assert.ok(firstAwait === -1 || changing < firstAwait, + 'screen:changing must fire before showScreen awaits anything — that is its entire purpose'); +}); + +test('the v3 shell reacts to screen:changed rather than wrapping showScreen', () => { + const src = fs.readFileSync(path.join(ROOT, 'static', 'v3', 'shell.js'), 'utf8'); + assert.match(scrub(src), /on\('screen:changed'/, 'shell.js must listen, not patch'); +});