Repository: launchbadge/sqlx
File: sqlx-sqlite/src/connection/mod.rs (Rust)

Code before:
        &mut self,
        name: &str,
        compare: impl Fn(&str, &str) -> Ordering + Send + Sync + 'static,
    ) -> Result<(), Error> {
        collation::create_collation(&mut self.guard.handle, name, compare)
    }

    /// Sets a progress handler that is invoked periodically during long running calls. If the progress callback
    /// returns `false`, then the operation is interrupted.
    ///
    /// `num_ops` is the approximate number of [virtual machine instructions](https://www.sqlite.org/opcode.html)
    /// that are evaluated between successive invocations of the callback. If `num_ops` is less than one then the
    /// progress handler is disabled.
    ///
    /// Only a single progress handler may be defined at one time per database connection; setting a new progress
    /// handler cancels the old one.
    ///
    /// The progress handler callback must not do anything that will modify the database connection that invoked
    /// the progress handler. Note that sqlite3_prepare_v2() and sqlite3_step() both modify their database connections
    /// in this context.
    pub async fn set_progress_handler<F>(&mut self, num_ops: i32, mut callback: F)
    where
        F: FnMut() -> bool + Send + 'static,
    {
        unsafe {
            let callback = NonNull::new_unchecked(&mut callback as *mut _);
            let handler = callback.as_ptr() as *mut _;
            self.guard.drop_progress_handler_callback();
            self.guard.progress_handler_callback = Some(Handler(callback));

            sqlite3_progress_handler(
                self.as_raw_handle().as_mut(),
                num_ops,
                Some(progress_callback::<F>),
                handler,
            );
        }
    }

    /// Removes a previously set progress handler on a database connection.
    pub async fn remove_progress_handler(&mut self) {
        unsafe {
            sqlite3_progress_handler(self.as_raw_handle().as_mut(), 0, None, 0 as *mut _);
            self.guard.drop_progress_handler_callback();
        }
    }
}

impl Drop for ConnectionState {
    fn drop(&mut self) {
        // explicitly drop statements before the connection handle is dropped

Review comment (suggestion):
:stop_sign: `NonNull` is just a wrapper for a raw pointer, it does _not_ allocate on its own. 

This is just taking a pointer to `callback` on the stack which falls out of scope at the end of the function.

Once again, your test isn't catching this because the callback doesn't capture any state and so is zero-sized.

Code after:
    /// See [`SqliteConnectOptions::collation()`] for details.
    pub fn create_collation(
        &mut self,
        name: &str,
        compare: impl Fn(&str, &str) -> Ordering + Send + Sync + 'static,
    ) -> Result<(), Error> {
        collation::create_collation(&mut self.guard.handle, name, compare)
    }

    /// Sets a progress handler that is invoked periodically during long running calls. If the progress callback
    /// returns `false`, then the operation is interrupted.
    ///
    /// `num_ops` is the approximate number of [virtual machine instructions](https://www.sqlite.org/opcode.html)
    /// that are evaluated between successive invocations of the callback. If `num_ops` is less than one then the
    /// progress handler is disabled.
    ///
    /// Only a single progress handler may be defined at one time per database connection; setting a new progress
    /// handler cancels the old one.
    ///
    /// The progress handler callback must not do anything that will modify the database connection that invoked
    /// the progress handler. Note that sqlite3_prepare_v2() and sqlite3_step() both modify their database connections
    /// in this context.
    pub fn set_progress_handler<F>(&mut self, num_ops: i32, mut callback: F)
    where
        F: FnMut() -> bool + Send + 'static,
    {
        unsafe {
            let callback_boxed = Box::new(callback);
            // SAFETY: `Box::into_raw()` always returns a non-null pointer.
            let callback = NonNull::new_unchecked(Box::into_raw(callback_boxed));
            let handler = callback.as_ptr() as *mut _;
            self.guard.remove_progress_handler();
            self.guard.progress_handler_callback = Some(Handler(callback));

            sqlite3_progress_handler(
                self.as_raw_handle().as_mut(),
                num_ops,
                Some(progress_callback::<F>),
                handler,
            );
        }
    }

    /// Removes the progress handler on a database connection. The method does nothing if no handler was set.
    pub fn remove_progress_handler(&mut self) {
        self.guard.remove_progress_handler();
    }
}

impl Drop for ConnectionState {
    fn drop(&mut self) {