open-network-stream: Wrong type argument: stringp, nil

[skybert]

This looks like a cool extension for Emacs, but I cannot get it to work with remote debugging.

I've added this to my .emacs:

(use-package dap-java
  :config
  (dap-register-debug-provider
   "java"
   (lambda (conf)
     (plist-put conf :debugPort 5005)
     (plist-put conf :host "localhost")
     conf))
  (dap-register-debug-template "Example Configuration"
                             (list :type "java"
                                   :request "launch"
                                   :args ""
                                   :name "Run Configuration"))
  )

But upon running dap-debug, selecting this or any other debug template, I get:

open-network-stream: Wrong type argument: stringp, nil

Do you have any idea why?

My versions are:

dap-mode-20180909.1854
lsp-java-20180906.637
GNU Emacs 25.2.1 (x86_64-pc-linux-gnu, GTK+ Version 3.22.11) of 2017-04-25

Cheers!

[yyoncho]

Can you do:

(toggle-debug-on-error)
(setq lsp-print-io t)
(setq dap-print-io t)

and then after retrying paste the content of *messages* buffer and the error callstack?

[skybert]

Sure:

lsp--stdio-wait: Content-Length: 139

{
  "jsonrpc": "2.0",
  "method": "workspace/executeCommand",
  "params": {
    "command": "vscode.java.resolveMainClass"
  },
  "id": 23
}
Output from language server: {
  "jsonrpc": "2.0",
  "method": "window/logMessage",
  "params": {
    "type": 3,
    "message": "11 Sep 2018, 16:08:46 >> workspace/executeCommand vscode.java.resolveMainClass"
  }
}
11 Sep 2018, 16:08:46 >> workspace/executeCommand vscode.java.resolveMainClass
Output from language server: {
  "jsonrpc": "2.0",
  "id": 23,
  "error": {
    "code": -32601,
    "message": "No delegateCommandHandler for vscode.java.resolveMainClass"
  }
}
Error from the Language Server: No delegateCommandHandler for vscode.java.resolveMainClass (Method not Found)
Entering debugger...

Debugger entered--Lisp error: (error "Unable to find main class.
Please check whether the server is configured propertly")
  signal(error ("Unable to find main class.\nPlease check whether the server is configured propertly"))
  error("Unable to find main class.\nPlease check whether the server is configured propertly")
  dap-java--select-main-class()
  dap-java--populate-launch-args((:type "java" :request "launch" :args "" :name "Run Configuration"))
  dap-java--populate-default-args((:type "java" :request "launch" :args "" :name "Run Configuration"))
  dap-debug((:type "java" :request "launch" :args "" :name "Run Configuration"))
  funcall-interactively(dap-debug (:type "java" :request "launch" :args "" :name "Run Configuration"))
  #<subr call-interactively>(dap-debug record nil)
  apply(#<subr call-interactively> dap-debug (record nil))
  call-interactively@ido-cr+-record-current-command(#<subr call-interactively> dap-debug record nil)
  apply(call-interactively@ido-cr+-record-current-command #<subr call-interactively> (dap-debug record nil))
  call-interactively(dap-debug record nil)
  command-execute(dap-debug record)
  #[257 "\306�!\262�\307\300!\203�

[yyoncho]

Can you paste the content of the messages buffer as well?

I believe that the jdt server is not configured with the debug extension, I suspect that you are probably using stock jdt instead of jdt eclipse che one you can fix that by making sure that you are using latest LSP Java and calling lsp-java-update-server

Also, please delete the part in the config section, it is overriding the default java function with the demo one. I will update the readme to make that clear.

(use-package dap-java)

[skybert]

Ok, that got me a bit further: M-x lsp-java-update-server. It indeed solves the error described in my original issue description.

I will continue tomorrow, would be awesome to get a good Java debugger in Emacs again (haven't had that since jdibug and dap-java looks even better than jdibug was.

[yyoncho]

I will update the readme and I will change the code to raise an error if the server is not configured correctly, since lsp-mode is not doing that. Meanwhile update the dap-mode with today's version because l have reverted wrongly submitted cl. If you hit any issue feel free to ping me.

[skybert]

Thanks @yyoncho!