> If merely making them immutable again makes tests failing then perhaps there is something wrong with these tests or there are other bugs which are needed to be fixed.

I've noticed that the test_pdb fails because it expected the a class method to have the __repr__ "some func" but it got "bound method some func at 0x0000000". This may be the affect of this apply-to-all.diff. Other tests failing were actually fixed in other issues but somehow apply-to-all.diff is suddenly triggering them I think. The most fatal test failures is the test_pdb and test_logging because after those tests failed there were some unexpected behaviors like other tests were executed randomly, segfault and most prominent is that they started compiling by themselves! These are the two tests we should really look into right now.