Remove BijectorsEnzymeExt on 1.11.1

[penelopeysm]

Description of old PR, no longer relevant

See #333 and the comment added to BijectorsEnzymeExt for context.

I can confirm that this doesn't error in all contexts (but I can't confirm that it has the desired effect, because we can't actually meaningfully test Enzyme on 1.11):

• Precompilation: doesn't crash
• Runtime using Enzyme; using Bijectors: doesn't crash
• Runtime using Bijectors; using Enzyme: doesn't crash

I tested this locally on Julia 1.11.1 and [email protected]. I've also tested on Julia 1.10.6.

In theory, the main downside of this is:

• The inlined code is specific for a particular version of Enzyme, in this case, v0.12.36. This is maybe not a big deal if we don't expect any changes in EnzymeChainRulesCoreExt. I notice that between that version and now there has only been one change to this file, which is to add a config argument. EnzymeAD/Enzyme.jl@ffcb7dd#diff-ca235e21f5e92c1ccdcd841ca2665d4e7d9222f3e29e6e0fce9f601f74745175

Overall, though, I think this is a better fix than #333, because it does address the root problem of us implicitly depending on the load order of the two extensions. It just introduces other problems (of maintainability) in the process, but hopefully the comment is clear enough and mitigates this.

Closes #332 by simply removing the code on 1.11.1+.

[yebai]

Feel free to disable these Enzyme rules and the code that depends on them.

We can reactivate these codes after JuliaLang/julia#56368 is merged and released.

[penelopeysm]

Thanks for finding that @yebai! That's exciting.

I wonder what happens on 1.10 though because the breakage on 1.10 isn't caused by the dependency chain but rather due to an inability to simultaneously have something as a dep of a main package and a dep of an extension (in our case, ChainRulesCore is both a dep of Bijectors, and of BijectorsEnzymeExt). Will have to do some testing.

[penelopeysm]

The 1.10 failure should be fixed now through a devious workaround of using Bijectors: ChainRulesCore rather than using ChainRulesCore itself.

[penelopeysm]

@willtebbutt @mhauru, I'm optimistic about this one 😄

CI is still failing for 1.11, but that's no longer because of the extension precompilation issue; it's because it's trying to load Tapir, which naturally doesn't work on 1.11.

#338 shows what happens if we were to replace Tapir -> Mooncake; I've kept it as a separate PR to make the diffs clearer. On that PR all CI tests pass except for:

• Enzyme on 1.11 (which we know is broken; we could disable it from running in CI too)
• one Mooncake error (which I haven't looked into, but since I have your eyes on it here...)
• one of the interface tests, which looks to me like a case of unlucky random number generation (which we can fix later by seeding the RNG).

If you like the looks of both, I suggest we could merge #338 into this, merge this into master, open issues for the other failing tests, then tag a new release, so that the precomp issue doesn't hold up other work.

[mhauru]

Assuming the unlucky RNG test passes (I'm rerunning it) I'd be happy to merge #338 and this. Marking Enzyme v1 CI to not run would be good too.

I think we should revisit this once hopefully Julia v1.11.2 fixes the problem for good, the right way (JuliaLang/julia#56368), and maybe by then Enzyme will be working with v1.11 too. Might end up keeping the code introduced in this, but with a version bound of ==v1.11.1, or might even remove it to simplify and raise an error saying "if you want to use Enzyme with Bijectors, you need some other, any other, version". Regardless, this seems like definitely an improvement over the current state, and good enough for now.

[penelopeysm]

The code is removed now (and replaced with a warning). Same deal as before – we should check CI on #338, merge that into this, and then merge this into master and release.

[yebai]

Thanks @penelopeysm!