Can't connect to multiple nrepls

[arohner]

Running cider git checkout of HEAD, 3487955

I'm trying to create multiple nrepl connections, to multiple processes, and can't. A typical workflow for me is to have a CLJ nrepl running, and a second to figwheel, for CLJS.

Steps:

M-x cider-connect "localhost" 6005
M-x cider-connect "localhost" 7888 (figwheel nrepl)

The first connection works just fine. The second connection is "defective". M-x cider-connect reports "Direct connection established", but emacs doesn't automatically open the second buffer. If I manually switch to "cider-repl localhost<2>", there is no repl prompt, and typing in the buffer has no effect.

If I kill both buffers, do the steps in opposite order, and get same result:

M-x cider-connect "localhost" 7888
M-x cider-connect "localhost" 6005

In this case, the 7888 buffer works correctly, and the 6005 buffer is defective.

The bug doesn't appear to have anything to do with figwheel, I can also reproduce it using two normal CLJ nrepls:

M-x cider-connect "localhost" 6005
M-x cider-connect "localhost" 6006

Note that connecting to the same process twice works fine:

M-x cider-connect "localhost" 6005
M-x cider-connect "localhost" 6005

In this case, both buffers work as expected.

[bbatsov]

Hmm, that's pretty odd. @expez @benedekfazekas @cichli Can you reproduce this problem?

[bbatsov]

@arohner I can't reproduce this. I'd suggest going through the "Troubleshooting" section of the README and debugging interactively the REPL init to see what goes wrong for you.

[arohner]

I've enabled toggle-debug-on-error. No popups. Nothing suspicious in Messages. Attempting to type in the 'broken' repl results in the following in nrepl-messages:

(--->
  ns  "user"
  op  "eval"
  session  "4f73b935-d209-4878-81f7-21c13430242e"
  code  "\n"
  id  "5"
)
(<-
  id  "5"
  session  "4f73b935-d209-4878-81f7-21c13430242e"
  status  ("unknown-session" "error")
)

[bbatsov]

Seems it's trying to evaluate code in some unknown session, but without being able to reproduce it we'll have hard time fixing it.

[lgrapenthin]

I think I have the same problem, however I can workaround by opening a different buffer than the first REPL before entering cider-connect. Btw. this problem existed in Cider 0.8 already.

[arrdem]

Bumping this because I hit it just now. With one nREPL connection to a work host, I was unable to open a second connection to the same host on CIDER 0.9

[bbatsov]

Can some of you investigate this in edebug. It's pretty simple and I can't do it myself as I can't reproduce it. Check out the troubleshooting section of the README for details.

[lgrapenthin]

The problem is that when a REPL is currently open, nrepl-connection-buffer is set to it. All requests are made to that repl buffer instead of the newly created buffer. A workaround is to modifiy nrepl-start-client-process so that nrepl-connection-buffer is nil before nrepl--init-client-sessions is invoked, so that the buffer is looked up in the connection ring. I'd make a PR but my knowledge of this codebase is too narrow to fix it appropriately.

[bbatsov]

OK, got it. That's why I couldn't reproduce this - I never started the second connection when in a REPL buffer.

@vspinu You authored this code. Would like to fix it or should I do this?

[vspinu]

That's why I couldn't reproduce this - I never started the second connection when in a REPL buffer.

Me too.

@vspinu You authored this code. Would like to fix it or should I do this?

Fixed.