make ChainRulesCore dependency into an extension

[KristofferC]

Shouldn't be merged until the Registrator deployment of JuliaRegistries/Registrator.jl#397 is done.

[codecov]

Codecov Report

Base: 100.00% // Head: 100.00% // No change to project coverage 👍

Coverage data is based on head (c9785e8) compared to base (41ca2a3).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff            @@
##            master       #12   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            2         3    +1     
  Lines           61        61           
=========================================
  Hits            61        61           

Impacted Files	Coverage Δ
src/with_ladj.jl	100.00% <ø> (ø)
ext/ChainRulesCoreExt.jl	100.00% <100.00%> (ø)

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.

[oschulz]

@KristofferC I hadn't been aware of Pkg extensions until just now (but I'm very much in favor of the concept!). If I understand the docs correctly this will be backward-compatible down to at least Julia v1.6, right? Do extensions eliminate the drawbacks of Requires.jl (no precompilation and often big hit on load time of stacks of packages)?

[KristofferC]

Should be backwards compatible to Julia 1.0.

Do extensions eliminate the drawbacks of Requires.jl (no precompilation and often big hit on load time of stacks of packages)?

Yes, that's the idea. These extensions get precompiled like a normal package.

[oschulz]

Yes, that's the idea. These extensions get precompiled like a normal package.

Oh, that is awesome!

[oschulz]

Shouldn't be merged until the Registrator deployment of JuliaRegistries/Registrator.jl#397 is done.

Do you know if that's deployed now?

[KristofferC]

Yes, it should be! So we can try this out.

[oschulz]

Ok, let's try it! :-)

[oschulz]

Seems to work like a charm with Julia v1.9.0-beta3:

julia> @time_imports import ChangesOfVariables
      0.6 ms  ChangesOfVariables

julia> @time_imports import ChainRulesCore
      0.1 ms  Compat
     58.9 ms  ChainRulesCore
      0.4 ms  ChangesOfVariables → ChainRulesCoreExt

@devmotion, if you have no objections I'll tag a ChangesOfVariables release with this?

[devmotion]

Sure, I'm really excited about weak dependencies 🙂

[oschulz]

Sure, I'm really excited about weak dependencies

Me too, I hope this will start a minor (maybe not so minor) revolution across the ecosystem.