gh-117139: A StackRef Debugging Mode by Fidget-Spinner · Pull Request #121134 · python/cpython

Can you try this on the full set of tests, just to see if it would be acceptable on CI?

I did. It fails

    test.test_gdb.test_pretty_print test_capi test_exceptions
    test_regrtest test_repl test_sys test_tracemalloc

mainly because they count allocations/test out of memory situations, and the hashtable adds random allocations which breaks their careful calculations.

On my computer on free threaded builds with the stackref debugging mode, it takes 5 minutes to run the whole test suite. macOS is the fastest/"cheapest" runner we have right now because Cirrus Labs is sponsoring bare-metal runners IIRC. Without stackref debug mode, it takes 2 min 7 s. So roughly a 2.5x slowdown. Factoring that in, the fastest Cirruslabs runners takes 6 min to complete on this PR. So it should take 15 minutes to run the whole test suite. We would need to skip those tests above too, as those are known failures.