The original implementation of this was really weird, so I restructed it
a lot while debugging, and am just gonna leave the restructured version.
Root cause of the segfault seems to be that upstream nixpkgs liburing
derivation is generating both static and dynamic libraries, causing
rocksdb to statically link liburing in a dynamic build, pulling in some
allocator stuff at the same time. I created a PR[1] to fix this upstream,
but it probably won't be available on nixos-unstable for quite a while,
so we can also patch it locally.
[1]: https://github.com/NixOS/nixpkgs/pull/314945
It turns out that this was actually fixed by
bec507d739 and
857ac42aac, but we didn't identify it at the
time. Notably, the `dynamic` devshell is still broken.
This is causing build failures on Mac:
> In file included from /tmp/nix-build-rocksdb-static-aarch64-apple-darwin-9.1.1.drv-0/source/memory/memory_allocator.cc:8:
> In file included from /tmp/nix-build-rocksdb-static-aarch64-apple-darwin-9.1.1.drv-0/source/memory/jemalloc_nodump_allocator.h:11:
> /tmp/nix-build-rocksdb-static-aarch64-apple-darwin-9.1.1.drv-0/source/port/jemalloc_helper.h:63:36: warning: unknown attribute '_rjem_malloc' ignored [-Wunknown-attributes]
> mallocx(size_t, int) JEMALLOC_ATTR(malloc) JEMALLOC_ALLOC_SIZE(1)
> ^~~~~~
> /nix/store/3bix0kzy670dyhhizri3dwb1qfj3sdpa-jemalloc-static-aarch64-apple-darwin-5.3.0/include/jemalloc/jemalloc.h:412:18: note: expanded from macro 'malloc'
> # define malloc je_malloc
> ^~~~~~~~~
> /nix/store/3bix0kzy670dyhhizri3dwb1qfj3sdpa-jemalloc-static-aarch64-apple-darwin-5.3.0/include/jemalloc/jemalloc.h:75:21: note: expanded from macro 'je_malloc'
> # define je_malloc _rjem_malloc
> ^~~~~~~~~~~~
> /nix/store/3bix0kzy670dyhhizri3dwb1qfj3sdpa-jemalloc-static-aarch64-apple-darwin-5.3.0/include/jemalloc/jemalloc.h:183:43: note: expanded from macro 'JEMALLOC_ATTR'
> # define JEMALLOC_ATTR(s) __attribute__((s))
Full build log at <https://girlboss.ceo/~strawberry/pb/ygJ3>. This is
likely fixable with patches to rocksdb, but not worth it since darwin is
only a dev platform.
CI is running `cargo build --all-features`, so we should be passing all
the features to nix as well.
The only thing this currently affects is the jemalloc_prof feature, but if
we add any non-default features that affect nix in the future they should
also be handled correctly now.
Some of the features affect nix dependencies, so we need to have a
full feature list available when constructing the nix derivation. This
incidentally fixes the bug where we weren't enabling jemalloc on rocksdb
in CI/devshells, because jemalloc is now a default feature. It does not
fix the more general class of that issue, where CI is performing an
`--all-features` build in a nix devshell built for default-features.
I am now passing `--no-default-features` to cargo, and having it use our
unified feature list rather than duplicating the unification inside cargo.
Without setting JEMALLOC_OVERRIDE, we end up linking to two different
jemalloc builds. Once dynamically, as a transitive dependency through
rocksdb, and a second time to the static jemalloc that tikv-jemalloc-sys
builds.
strawberry