Add a simple nrepl-server task in cider.tasks

[arichiardi]

First step towards the new cider nrepl integration.

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• The commits are consistent with our contribution guidelines
• You've updated the README (if adding/changing middleware)

[codecov]

Codecov Report

Merging #532 into master will decrease coverage by 0.46%.
The diff coverage is 4.54%.

@@            Coverage Diff             @@
##           master     #532      +/-   ##
==========================================
- Coverage   72.95%   72.48%   -0.47%     
==========================================
  Files          36       36              
  Lines        2281     2297      +16     
  Branches      134      134              
==========================================
+ Hits         1664     1665       +1     
- Misses        483      498      +15     
  Partials      134      134

Impacted Files	Coverage Δ
src/cider/tasks.clj	5.55% <0%> (-5.56%)	⬇️
src/cider_nrepl/main.clj	20% <7.69%> (-1.74%)	⬇️

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[bbatsov]

That looks simple enough!

[arichiardi]

If I understand correctly - if this is what we want for boot - we basically can handle the cider-boot-parameters in cider directly.

If cider-jack-in-command sees that the project depends on:

• [org.clojure/tools.nrepl "0.2.13"] -> "repl -s -H :: wait" (current behavior)
• [nrepl "0.3.1"] -> "repl -s -H :: wait" (current behavior)
• [nrepl "0.4.0"] -> "nrepl-server wait"

Problem is cider-boot-parameters is a defcustom so we probably need to take away the repl part because it suddenly becomes dynamic.

Another approach would be to always call nrepl-server:

(defcustom cider-boot-parameters
  "nrepl-server -s -H :: wait"
  "Params passed to boot to start an nREPL server via `cider-jack-in'."
  :type 'string
  :group 'cider
  :safe #'stringp
  :package-version '(cider . "0.9.0"))

And detect the nrepl version in the task.

EDIT: I like the latter better but it also means the we need to replicate the options we are using / are commonly used in reply - server. In particular the two above are:

-s, --server      Start REPL server only.                         [we get this]
-H, --host HOST   HOST sets the host client connects to.

Which consequently means we need to modify this. Writing down this things here for future reference.

[bbatsov]

CIDER won't be able to work with both versions of nREPL anyways, so there's no need to complicate this. I'm ok with the second option.

[arichiardi]

Ok so the task accepts -p|--port and -b|--bind like boot's task so we can now do this:

nrepl-server -b :: wait

The -b to localhost is the default too.

[arichiardi]

I also made the whole thing a bit more robust - we should probably merge nrepl/nrepl#34 before this just to make sure things are ok.

[arichiardi]

The error in the tests is unrelated to the change. It is a zip error.

[bbatsov]

Nice!

Now we just need the same time for lein and then we can update the the cider-jack-in commands and finally switch to our new nREPL.