Bug: fluid.bufstats~ can crash when mixing threads

[rconstanzo]

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It seems that fluid.bufstats~ can insta-crash when it is getting messages from mixed threads, specifically receiving weights in it's right-most inlet in the high-priority thread, while the object is in @blocking 1 and then also receiving buffers upstream from the high-priority thread.

So I think the steps are:

1. have fluid.bufstats~ @blocking 1
2. send weights buffer to right inlet from high-priority thread
3. send buffer into left inlet from high-priority thread

Sometimes this gives an Invalid weights error message (as mentioned below) but other times it will just crash, presumably when read/writing from unsafe memory.

This is happening in the patch outlined in this thread:
https://discourse.flucoma.org/t/creating-a-filter-from-spectral-moments-fluid-spectralshape/

Specifically this version of the patch:
https://discourse.flucoma.org/uploads/short-url/nkoDHX3alGOt8e2sudrKHQsmq3J.zip

The offending abstraction is dk.spectralshapeframe which has three instances of fluid.stats~ in it, and only one of which was having it's @blocking mode updated automatically (I missed the connection when building the patch).

If you run the patch for any amount of time you will see the error messages, and eventually a crash.

Here's a crash report:

bufstats crash.zip

What was the expected result?

Complaining about threading, which it did do as well:

fluid.bufstats~: Invalid weights

But sometimes it would not complain and instead crash.

What was the actual result?

An insta-crash.

What operating system were you using?

Mac

Operating system version

macOS 15.2

FluCoMa Version

1.0.8+sha.0a9327e.core.sha.7dfcc220