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Comment by tensor | Hacker News Reader

Spec is still alpha as far as I'm aware. They decided to break spec off into it's own library because it was holding up the release of 1.9.

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The API is still subject to change (alpha) but those changes are not expected to be dramatic at this point.

I'm looking forward to hearing a long-form rational of the :args :ret :fn function instrumenting decisions, and seeing if the devs see it as an easy choice or up for debate.

It feels really uncomfortable declaring a full spec for a function & instrumenting it, then getting feedback if the args don't conform to spec but Clojure being A-OK if the return value doesn't.

I understand well that in theory the functioning of a function can be fully checked in a proactive test framework, but the process for testing return values is way clunkier and less fun than testing argument values. It just seems weird that the function has a spec, the function doesn't conform and Clojure doesn't seem to be bothered.

I can see it will only be a matter of days until I have Orchestra installed for all my projects.

I'm not familiar with Spec, but what you're describing sounds like enforcing preconditions but not postconditions by default, which is what most DbC frameworks (or languages with intrinsic support) normally do. The idea being that most of the time, you're running library code, and you want to validate what you're passing in, but you trust it to do the right thing for any input that is valid.

That’s fine, and makes sense, but without hacks, it is not possible to turn on ret checking in your tests that are not generative tests - so no post condition checks in the rest of your test suite.

I believe this is a missed opportunity to find bugs.

Why are all the relevant changes for a point release alpha? Why do you reckon this isn’t 1.9-alpha?

There are also many changes in the language itself (see https://github.com/clojure/clojure/blob/master/changes.md), none of which are alpha.

The things that are really the new big drivers are pieces that are not inside the language (other than a few spec integration points). Those things are significant pieces of work that are imminently usable now, but not quite final yet. In the interest of getting this work into more hands, we made a new release of the language with those parts marked as alpha.

The modularized spec allows us to continue releasing new versions (and for you to use them) with Clojure 1.9.0. Eventually spec will leave alpha and we will consider that a finalized part of the language. Similarly, tools.deps is still evolving as we work on it but the tools should remain fairly stable.

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