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fix(capture): sample forced states in one CDP session #339

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Merged
BenSheridanEdwards merged 1 commit into from
Aug 1, 2026
Merged

fix(capture): sample forced states in one CDP session #339

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9 changes: 9 additions & 0 deletions CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,15 @@ this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm

## [Unreleased]

## [4.7.4] - 2026-08-01

### Fixed

- **Forced interaction states are sampled in the CDP session that applies them.**
The computed-style subtree read no longer crosses into Playwright's separate
protocol session after forcing `:hover`, `:focus`, or `:active`. This removes
intermittent phantom state deltas on unchanged controls in hydrated apps.

## [4.7.3] - 2026-08-01

### Fixed
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4 changes: 2 additions & 2 deletions package-lock.json
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2 changes: 1 addition & 1 deletion package.json
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
{
"name": "styleproof",
"version": "4.7.3",
"version": "4.7.4",
"description": "Catch every CSS change before it ships — review PRs and certify refactors by the browser's computed styles, not pixels. Works with any styling system.",
"keywords": [
"playwright",
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13 changes: 11 additions & 2 deletions src/capture.ts
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Expand Up @@ -721,6 +721,15 @@ async function settleForcedState(client: CDPSession, selector: string): Promise<
return result.value === true;
}

async function snapSubtreeInSession(client: CDPSession, args: SubtreeArgs): Promise<Snap> {
const { result, exceptionDetails } = await client.send('Runtime.evaluate', {
expression: `(${snapSubtree.toString()})(${JSON.stringify(args)})`,
returnByValue: true,
});
if (exceptionDetails) throw new Error(`styleproof: forced-state snapshot failed: ${exceptionDetails.text}`);
return (result.value ?? {}) as Snap;
}

// Forced pseudo-class states on interactive elements, via CDP so no real
// mouse or focus is involved and parent-state descendant rules still apply.
async function captureForcedStates(
Expand Down Expand Up @@ -758,7 +767,7 @@ async function captureForcedStates(
console.warn(`styleproof: interactive element ${id} detached before forced-state capture; skipping it.`);
continue;
}
const baseSnap: Snap = await page.evaluate(snapSubtree, { selector, index: 0 });
const baseSnap = await snapSubtreeInSession(client, { selector, index: 0 });
for (const [stateName, forcedPseudoClasses] of Object.entries(STATE_SETS)) {
await client.send('CSS.forcePseudoState', { nodeId, forcedPseudoClasses });
if (!(await settleForcedState(client, selector))) {
Expand All @@ -767,7 +776,7 @@ async function captureForcedStates(
console.warn(`styleproof: interactive element ${id} detached during forced-state capture; skipping it.`);
break;
}
const forcedSnap: Snap = await page.evaluate(snapSubtree, { selector, index: 0 });
const forcedSnap = await snapSubtreeInSession(client, { selector, index: 0 });
await client.send('CSS.forcePseudoState', { nodeId, forcedPseudoClasses: [] });
await settleForcedState(client, selector);
const delta = deltaBetween(baseSnap, forcedSnap);
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8 changes: 5 additions & 3 deletions test/smoke.e2e.spec.ts
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Expand Up @@ -81,10 +81,12 @@ test('waits for every forced pseudo-state transition before reading computed sty
button:active { border-color: rgb(7, 8, 9); }
</style></head><body>${Array.from({ length: 24 }, (_, i) => `<button>Action ${i}</button>`).join('')}</body></html>`;

const first = await captureFixture(page, html);
const second = await captureFixture(page, html);
const captures = [];
for (let i = 0; i < 8; i++) captures.push(await captureFixture(page, html));
const [first, ...replays] = captures;

expect(diffStyleMaps(first, second), 'independent forced-state sweeps are byte-equivalent').toEqual([]);
for (const replay of replays)
expect(diffStyleMaps(first, replay), 'independent forced-state sweeps are byte-equivalent').toEqual([]);
for (const [path] of Object.entries(first.elements).filter(([, entry]) => entry.tag === 'button')) {
expect(first.states[path]?.hover, `${path} captured :hover`).toBeTruthy();
expect(first.states[path]?.focus, `${path} captured :focus-visible`).toBeTruthy();
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