Hi Guile devs, We are debugging a GC issue in LilyPond when used with Guile 2.2, and could use some help.
The issue and associated Merge Request are here: https://gitlab.com/lilypond/lilypond/-/issues/6218 https://gitlab.com/lilypond/lilypond/-/merge_requests/1035 We are using smobs with custom mark and free functions for interfacing with our C++ code. We are seeing that sometimes mark functions are called on smobs which have their dependencies already collected, leading to crashes. We can change our mark routines to avoid the crash, but it's unclear to us if this behavior is intended or not, and we worry that this will come back to bite us in the future. On the one hand, the docs for smobs state "must assume .. all SCM values that it references have already been freed and are thus invalid", which suggests that smob freeing happens in random order, which is consistent with what we see. On the other hand, Guile sets up BDWGC with GC_java_finalization=1, which should keep GC dependencies of an object alive until the object itself is finalized, and I think we have observed the mark calls that make this happen. which of the two is it? (I am seeing the problem on Fedora 35, with Guile 2.2.7 and libgc 8.0.4) -- Han-Wen Nienhuys - hanw...@gmail.com - http://www.xs4all.nl/~hanwen
