Pages Router: `next/head` manager re-executes inline scripts on re-render
#1 473 ouverte le 22 mai 2026
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Description
This issue was created by an agent analysing CI failures from the Next.js Deploy Suite (vinext
mainvs Next.jsv16.2.6, 2026-05-22).
Problem
When the Pages Router head manager updates <Script> tags during component re-renders, Next.js dedupes by src and does not re-execute already-loaded scripts. vinext re-executes them, causing the test's side-effect array to grow beyond ["src-1.js"]. The same issue applies whether or not a CSP nonce is set.
After re-render, scripts re-executed: side-effect array exceeds expected length
Estimated Impact
~2 test failures across the deploy suite.
Affected Test Suites
test/e2e/nonce-head-manager/index.test.ts(2 failures)
Recommendation
-
Reproduce first in vinext's own test suite. Add a Pages Router page that toggles state and re-renders a
<Script src="./once.js">. Assert the script executes exactly once. -
Track loaded
<Script>sources in the head manager. Maintain aSet<src>of already-injected scripts and skip re-injection during head reconciliation. -
Cover the nonce variant. Same dedup must apply when scripts carry a CSP nonce.