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fix(core): add lint rule for infinite GSAP repeat #218

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Merged
miguel-heygen merged 2 commits into from
Apr 7, 2026
Merged

fix(core): add lint rule for infinite GSAP repeat #218

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844bb80
fix(core): add lint rule for infinite GSAP repeat
miguel-heygen Apr 7, 2026
17791d1
fix(core): prevent false positive on repeat: -10 in lint rule
miguel-heygen Apr 7, 2026
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53 changes: 53 additions & 0 deletions packages/core/src/lint/rules/gsap.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -411,4 +411,57 @@ describe("GSAP rules", () => {
expect(finding).toBeDefined();
expect(finding?.severity).toBe("error");
});

it("errors on repeat: -1 (infinite repeat breaks capture engine)", () => {
const html = `
<html><body>
<div data-composition-id="main" data-width="1920" data-height="1080"></div>
<script src="https://cdn.jsdelivr.net/npm/gsap@3/dist/gsap.min.js"></script>
<script>
window.__timelines = window.__timelines || {};
const tl = gsap.timeline({ paused: true });
tl.to("#spinner", { rotation: 360, duration: 0.8, repeat: -1, ease: "none" }, 0);
window.__timelines["main"] = tl;
</script>
</body></html>`;
const result = lintHyperframeHtml(html);
const finding = result.findings.find((f) => f.code === "gsap_infinite_repeat");
expect(finding).toBeDefined();
expect(finding?.severity).toBe("error");
expect(finding?.message).toContain("repeat: -1");
});

it("does not error on finite repeat values", () => {
const html = `
<html><body>
<div data-composition-id="main" data-width="1920" data-height="1080"></div>
<script src="https://cdn.jsdelivr.net/npm/gsap@3/dist/gsap.min.js"></script>
<script>
window.__timelines = window.__timelines || {};
const tl = gsap.timeline({ paused: true });
tl.to("#spinner", { rotation: 360, duration: 0.8, repeat: 4, ease: "none" }, 0);
window.__timelines["main"] = tl;
</script>
</body></html>`;
const result = lintHyperframeHtml(html);
const finding = result.findings.find((f) => f.code === "gsap_infinite_repeat");
expect(finding).toBeUndefined();
});

it("does not false-positive on repeat: -10 (invalid GSAP but not infinite)", () => {
const html = `
<html><body>
<div data-composition-id="main" data-width="1920" data-height="1080"></div>
<script src="https://cdn.jsdelivr.net/npm/gsap@3/dist/gsap.min.js"></script>
<script>
window.__timelines = window.__timelines || {};
const tl = gsap.timeline({ paused: true });
tl.to("#box", { x: 100, duration: 1, repeat: -10 }, 0);
window.__timelines["main"] = tl;
</script>
</body></html>`;
const result = lintHyperframeHtml(html);
const finding = result.findings.find((f) => f.code === "gsap_infinite_repeat");
expect(finding).toBeUndefined();
});
});
28 changes: 28 additions & 0 deletions packages/core/src/lint/rules/gsap.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -482,6 +482,34 @@ export const gsapRules: Array<(ctx: LintContext) => HyperframeLintFinding[]> = [
return findings;
},

// gsap_infinite_repeat
({ scripts }) => {
const findings: HyperframeLintFinding[] = [];
for (const script of scripts) {
const content = script.content;
// Match repeat: -1 in GSAP tweens or timeline configs
const pattern = /repeat\s*:\s*-1(?!\d)/g;
let match: RegExpExecArray | null;
while ((match = pattern.exec(content)) !== null) {
const contextStart = Math.max(0, match.index - 60);
const contextEnd = Math.min(content.length, match.index + match[0].length + 60);
const snippet = content.slice(contextStart, contextEnd).trim();
findings.push({
code: "gsap_infinite_repeat",
severity: "error",
message:
"GSAP tween uses `repeat: -1` (infinite). Infinite repeats break the deterministic " +
"capture engine which seeks to exact frame times. Use a finite repeat count calculated " +
"from the composition duration: `repeat: Math.ceil(duration / cycleDuration) - 1`.",
fixHint:
"Replace `repeat: -1` with a finite count, e.g. `repeat: Math.ceil(totalDuration / singleCycleDuration) - 1`.",
snippet: truncateSnippet(snippet),
});
}
}
return findings;
},

// scene_layer_missing_visibility_kill
({ scripts, tags }) => {
const findings: HyperframeLintFinding[] = [];
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