On Thu, 2018-07-05 at 05:16 +0100, jnqnfe at gmail.com wrote: > The internal operation_set_state function already returns early if the > new state is the same as the existing state. The attached patch extends > this to return early if already in a finalised (done/cancelled) state, > i.e. blocks attempts to re-finalise into a different state. > > This helps avoid unlinking more than once (or crashing on ref count > assertion). > > I was not certain whether an assertion would be a better alternative - > with such a crash helping highlight usage problems... > > The situation that lead to this was the thought of someone stupidly > trying to pa_operation_cancel() a callback within the callback > execution itself, while designing a solution for a memory leak related > to cancellation within my Rust binding. While no-one should do such a > thing, if they did, they'd either trip up a ref count assertion, or the > operation would be unlinked twice, which would be bad. It's a simple > thing to catch and mitigate, and could prove to be a useful > bulletproofing measure for this function in general. Thanks! This seems like a good approach to the problem. I applied the patch. Please write the change rationale to the commit message in the future. I copied your explanation to the commit message myself. -- Tanu https://www.patreon.com/tanuk https://liberapay.com/tanuk
