Calva: Calva REPL lags when evaluation throws an error

[julianwegkamp]

When an evaluation in the Calva REPL throws an Exception it will take a couple of seconds (5 to 10 or so) to show the exception and return the prompt. E.g.

clj::user=> 
(/ 1 0)

Some seconds...

; Execution error (ArithmeticException) at user/eval21385 (REPL:21).
; Divide by zero

Tested with jack-in Clojure CLI (empty deps.edn), leiningen and Clojure CLI started in the a terminal window + connect

Visual Studio Code:
Version: 1.52.1
Commit: ea3859d4ba2f3e577a159bc91e3074c5d85c0523
Date: 2020-12-16T16:30:02.420Z (1 wk ago)
Electron: 9.3.5
Chrome: 83.0.4103.122
Node.js: 12.14.1
V8: 8.3.110.13-electron.0
OS: Darwin x64 18.7.0

Calva:
Version: 2.0.138 and 2.0.134

[PEZ]

With the help of @zelark , I've found that switching off wifi makes the lag go away.

Also, after some experimentation, I think we can get rid of the problem by upgrading the cider-nrepl et al versions used for jack-in.

[bpringe]

Wifi? :thinking: Very strange.

[PEZ]

The n in nREPL does stand for ”network” which is why I then tried if upgrading those helped. Haha.

[julianwegkamp]

I just checked with Little Snitch to see what network connections are set up when an exception is thrown. I see connections being made to clojuredocs-edn.netlify.com and clojuredocs-edn.netlify.app. When I deny connections to both the REPL functions as expected. Disabling only one, will improve the response time of the REPL (subjectively at least).

[PEZ]

Thanks, @julianwegkamp, that explains why this suddenly started to be a problem. @bbatsov mentioned something about a change in clojuredocs.

In any case, latest Calva, v2.0.140, bumps jack-in to latest cider-nrepl and that fixes the issue for us.

[bpringe]

Now I'm really curious as to what library was retrieving info from those domains (if I understand correctly). I don't see anything about them in nrepl, cider-nrepl, orchard, or Calva.

[bpringe]

Scratch that, I see orchard and cider-nrepl do things with clojuredocs. I'm guessing it was from one of those.

[bbatsov]

Yeah, the older version was fetching the data from ClojureDocs the first time someone used the info op. This was a big mistake for various reasons and we've later switched to just bundling a snapshot of the data with orchard.