source-academy / py-slang / 31434140875

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Committed by web-flow

Commit Message

Pyodide: fix a captured callback being destroyed before its returned closure calls it (#433)

* Pyodide: fix a callback captured by a returned closure being destroyed early

A Python callback crossing into a module call arrives as a borrowed
PyProxy, which pyodide auto-destroys once the specific async JS call
it was passed into (the run_sync-driven call) resolves. That's fine
when the callback is invoked during that same call, but breaks the
SICP `repeated` shape: `f = repeat(square, 4); f(3)` — the closure
`repeat` returns captures `square` for a call that happens later, in
a separate statement, after repeat(...)'s own call (and its borrow)
has already ended. Symptom: pyodide.ffi.JsException: "This borrowed
proxy was automatically destroyed at the end of an asynchronous
function call."

Fix: proxy.copy() before capturing the callback in the closure that
outlives the original call, making an independent proxy unaffected by
the borrowed one being destroyed.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012N4SJu6EZMawWgsGhJkHpx

* Fix prettier formatting

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012N4SJu6EZMawWgsGhJkHpx

---------

Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>

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