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LibsqlConnection::drop called local::Connection::disconnect(), and then the inner local::Connection's own Drop called disconnect() again on the same raw handle, so every connection close ran sqlite3_close_v2() twice. The second call reads the freed sqlite3 struct. It usually returns SQLITE_MISUSE harmlessly, but when another thread has reused the freed block first, sqlite walks garbage and crashes. This surfaced in libsql-js as an intermittent access violation at worker-thread exit on Windows, where the finalizers close many connections in a burst. Make disconnect() idempotent by forgetting the handle after closing it, and drop the redundant Drop impl on LibsqlConnection, since the inner connection already closes on drop. Add a regression test that counts sqlite3_close_v2() calls through a cfg(test) thread-local and checks a drop closes the handle exactly once, both for a plain drop and when a statement is the last owner. It fails with 2 closes on the old code.
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LibsqlConnection::drop called local::Connection::disconnect(), and then the inner local::Connection's own Drop called disconnect() again on the same raw handle, so every connection close ran sqlite3_close_v2() twice. The second call reads the freed sqlite3 struct. It usually returns SQLITE_MISUSE harmlessly, but when another thread has reused the freed block first, sqlite walks garbage and crashes. This surfaced in libsql-js as an intermittent access violation at worker-thread exit on Windows, where the finalizers close many connections in a burst.
Make disconnect() idempotent by forgetting the handle after closing it, and drop the redundant Drop impl on LibsqlConnection, since the inner connection already closes on drop.
Add a regression test that counts sqlite3_close_v2() calls through a cfg(test) thread-local and checks a drop closes the handle exactly once, both for a plain drop and when a statement is the last owner. It fails with 2 closes on the old code.