TestConversion::test_cache randomly crashing on macOS about pyvips HOT 3 OPEN

I can't reproduce the crash in Docker on ubuntu:cosmic (18.10) with the same glib version (2.56.1) and libvips / pyvips master, so it appears to only affect macOS or maybe clang vs gcc.

from pyvips.

I should be able to try some tests today.

I hope it's something simple. The cache operator is horribly complicated, and debugging a race in there would be a nightmare :(

from pyvips.

I did a few tests, though none of them gave an interesting result.

Test program:

#!/bin/bash

test=$HOME/GIT/pyvips/tests/test_conversion.py::TestConversion::test_cache

for i in {1..200}; do
  echo "Try $i ..."
  if ! python3 -m pytest -q $test; then
    exit 1
  fi
done

1. git master libvips, ubuntu 18.04, gcc 7.3 ... no crash.
2. git master libvips, ubuntu 18.04, clang 6.0 ... no crash.

I'll have a go on macOS tonight.

from pyvips.