fix: memory leak in Link due to IntersectionObserver

[SimonSiefke]

Details

Docusaurus Link created a new callback ref on every render. React detached the old ref with null, but that path did not disconnect its IntersectionObserver, so the document's observer controller retained the old callback closure.

Change

Keep the callback ref stable while its inputs are unchanged, and disconnect and clear the active observer whenever the ref target changes or unmounts.

Before

When navigating between Playwright's Installation and Writing tests pages 37 times, the observer callback, innerRef, and interaction callback each grow by 3,922 instances:

After

No more matching Link observer leak is detected.

Test Video

test-video.webm

Additional Info

• PR is AI-generated
• Model: Codex (GPT-5.6)
• Worktime: 46 minutes, 38 seconds

[netlify]

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[slorber]

LGTM thanks!

I could confirm with Chrome devtools memory heap snapshots that IntersectionObserver is leaking in prod, and not in this deploy preview PR. The prefetching behavior on viewport enter keeps working as before.