[Bug] Cannot read property 'capabilities' of null when running GHDL-LS LSP Server

[pidgeon777]

We're trying to run ghdl-ls on Neovim with coc.nvim, one of its LSP clients.

An error occurs when doing that, we're trying to understand if this is a bug coc.nvim side or ghdl-ls side.

Here is the necessary info:

Result from CocInfo

## versions

vim version: NVIM v0.4.4
node version: v14.15.4
coc.nvim version: 0.0.80-50544406f0
coc.nvim directory: C:\Neovim\config\nvim\plugged\coc.nvim
term: undefined
platform: win32

## Log of coc.nvim

2021-01-31T15:54:27.641 INFO (pid:24080) [services] - registered service "languageserver.ghdlLS"
2021-01-31T15:54:27.883 INFO (pid:24080) [plugin] - coc.nvim 0.0.80-50544406f0 initialized with node: v14.15.4 after 308ms
2021-01-31T15:54:30.772 INFO (pid:24080) [attach] - receive notification: showInfo []

Describe the bug

I defined a LSP entry in the coc-settings.json file, this involve running the ghdl-ls executable when analyzing VHDL files.
When one of those VHDL files is opened, coc.nvim detect it and start the ghdl-ls LSP Server, but an error is generated, the following:

Cannot read property 'capabilities' of null

I'm using other VHDL LSP Servers with success, which are currently disabled, but this issue only occurs when using ghdl-ls.

Reproduce the bug

• Create file mini.vim with：

" -----------------------------
" Paths
" -----------------------------

let s:ghdl_p      = 'C:\GHDL\bin'
let s:ghdl_ls_p   = 'C:\Users\pcuser\.local\bin'

if (has('win32') || has('win64'))
 if !executable('ghdl')
   if (isdirectory(s:ghdl_p))
     let $PATH .= ';' . s:ghdl_p
   endif
 endif

 if !executable('ghdl-ls')
   if (isdirectory(s:ghdl_ls_p))
     let $PATH .= ';' . s:ghdl_ls_p
   endif
 endif

endif

" -----------------------------

set nocompatible
set runtimepath^=C:\Neovim\config\nvim\plugged\coc.nvim
filetype plugin indent on
syntax on
set hidden

• Start (neo)vim with command: vim -u mini.vim

• Operate vim.

My coc-settings.json:

{
	"suggest.autoTrigger": "always",

	"diagnostic.messageDelay": 0,

	"suggest.triggerCompletionWait" : 30,
	"signature.triggerSignatureWait": 200,

	"languageserver": {
		"ghdlLS": {
			"enable": true,
			"trace.server": "verbose",
			"command": "ghdl-ls",
			"filetypes": [
				"vhdl"
			],
                        "trace.server": "verbose"
		}
	},

	"snippets.userSnippetsDirectory": "$VIMCONFIG/UltiSnips"
}

LSP server config file hdl-prj.json:

{
    "options": {
        "ghdl_analysis": [
            "--workdir=work",
            "--ieee=synopsys",
            "-fexplicit"
        ]
    },
    "files": [
        { "file": "C:/VHDL/entity.vhd", "language": "vhdl" }
    ]
}

hdl-prj.json path:

C:\Test\hdl-prj.json

set pwd? result in Neovim:

C:\Test

ghdl-ls manual execution test in Neovim:

:!ghdl-ls --version
ghdl-ls 1.0-dev

The Issue

It occurs when I load the file added to the LSP config project, or any file of the VHDL type.

Coc.nvim returns:

[coc.nvim] Caught exception while handling initialize, see VHDL language server output for details.
[coc.nvim] Cannot read property 'capabilities' of null
[coc.nvim] Server languageserver.ghdlLS failed to start: TypeError: Cannot read property 'capabilities' of null

CocCommand workspace.showOutput shows an empty buffer.

[pidgeon777]

Here is the issue created on coc.nvim repository:

neoclide/coc.nvim#2859

[tgingold]

It looks like that's 'capabilities' from the client that generates the error. Can you log the whole exchange ? Just use: `export GHDL_LS_TRACE=ghdl-ls` This will create two files.

[pidgeon777]

Pardon me, where should I put that command? For example:

• Vim init file
• coc-settings.json

and where should I expect the files to be generated?

[tgingold]

It's a shell command, so set the variable before invoking nvim. The files are created in the current directory.

[tgingold]

If you are using windows, you can also add the option '--trace-file=ghdl-ls' when invoking the ghdl-ls server.

[pidgeon777]

I've to add that I'm currently running a ghdl-ls executable which I just built on my Windows 10 machine. I'm able to run it without any shell, just Windows 10 Command Prompt:

[pidgeon777]

If you are using windows, you can also add the option '--trace-file=ghdl-ls' when invoking the ghdl-ls server.

Sorry, I just noticed your post. I'll try right now.

[pidgeon777]

ghdl-ls.in:

Content-Length: 3023



{"jsonrpc":"2.0","id":0,"method":"initialize","params":{"processId":17560,"rootPath":"C:\\Test","rootUri":"file:///c%3A/Test","capabilities":{"workspace":{"applyEdit":true,"workspaceEdit":{"documentChanges":true,"resourceOperations":["create","rename","delete"],"failureHandling":"textOnlyTransactional"},"didChangeConfiguration":{"dynamicRegistration":true},"didChangeWatchedFiles":{"dynamicRegistration":true},"symbol":{"dynamicRegistration":true,"symbolKind":{"valueSet":[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26]},"tagSupport":{"valueSet":[1]}},"executeCommand":{"dynamicRegistration":true},"configuration":true,"workspaceFolders":true},"textDocument":{"publishDiagnostics":{"relatedInformation":true,"versionSupport":false,"tagSupport":{"valueSet":[1,2]}},"synchronization":{"dynamicRegistration":true,"willSave":true,"willSaveWaitUntil":true,"didSave":true},"completion":{"dynamicRegistration":true,"contextSupport":true,"completionItem":{"snippetSupport":true,"commitCharactersSupport":true,"documentationFormat":["markdown","plaintext"],"deprecatedSupport":true,"preselectSupport":true,"tagSupport":{"valueSet":[1]}},"completionItemKind":{"valueSet":[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25]}},"hover":{"dynamicRegistration":true,"contentFormat":["markdown","plaintext"]},"signatureHelp":{"dynamicRegistration":true,"contextSupport":true,"signatureInformation":{"documentationFormat":["markdown","plaintext"],"activeParameterSupport":true,"parameterInformation":{"labelOffsetSupport":true}}},"definition":{"dynamicRegistration":true},"references":{"dynamicRegistration":true},"documentHighlight":{"dynamicRegistration":true},"documentSymbol":{"dynamicRegistration":true,"symbolKind":{"valueSet":[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26]},"hierarchicalDocumentSymbolSupport":true,"tagSupport":{"valueSet":[1]}},"codeAction":{"dynamicRegistration":true,"isPreferredSupport":true,"codeActionLiteralSupport":{"codeActionKind":{"valueSet":["","quickfix","refactor","refactor.extract","refactor.inline","refactor.rewrite","source","source.organizeImports"]}}},"codeLens":{"dynamicRegistration":true},"formatting":{"dynamicRegistration":true},"rangeFormatting":{"dynamicRegistration":true},"onTypeFormatting":{"dynamicRegistration":true},"rename":{"dynamicRegistration":true,"prepareSupport":true},"documentLink":{"dynamicRegistration":true,"tooltipSupport":true},"typeDefinition":{"dynamicRegistration":true},"implementation":{"dynamicRegistration":true},"declaration":{"dynamicRegistration":true},"colorProvider":{"dynamicRegistration":true},"foldingRange":{"dynamicRegistration":true,"rangeLimit":5000,"lineFoldingOnly":true},"selectionRange":{"dynamicRegistration":true}},"window":{"workDoneProgress":true}},"initializationOptions":{},"trace":"verbose","workspaceFolders":[],"clientInfo":{"name":"coc.nvim","version":"0.0.80"},"workDoneToken":"b17acdbd-f76c-47b8-b4cb-559c9513315f"}}Content-Length: 58



{"jsonrpc":"2.0","id":1,"method":"shutdown","params":null}

ghdl-ls.out:

Content-Length: 168



{"jsonrpc":"2.0","method":"window/showMessage","params":{"type":1,"message":"Caught exception while handling initialize, see VHDL language server output for details."}}Content-Length: 38



{"jsonrpc":"2.0","id":0,"result":null}Content-Length: 38



{"jsonrpc":"2.0","id":1,"result":null}

[tgingold]

I have the impression you didn't install the libraries. You should first install ghdl before installing the LSP server. If this is the case, the error message has to be improved.

[pidgeon777]

I already built GHDL through MSYS2. Here is some info regarding the built executable:

C:\GHDL\bin>ghdl --version
GHDL 1.0-dev (tarball) [Dunoon edition]
 Compiled with GNAT Version: 10.2.0
 mcode code generator
Written by Tristan Gingold.

Copyright (C) 2003 - 2021 Tristan Gingold.
GHDL is free software, covered by the GNU General Public License.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

C:\GHDL\bin>ghdl --disp-config
command_name: C:\GHDL\bin\ghdl.exe
command line prefix (--PREFIX): (not set)
environment prefix (GHDL_PREFIX): (not set)
exec prefix (from program name): C:\GHDL

library prefix: C:\GHDL\lib/ghdl
library directory: C:\GHDL\lib/ghdl
default library paths:
 C:\GHDL\lib/ghdl\ieee\v93\
 C:\GHDL\lib/ghdl\

I'm happy to provide all of the necessary info and conducts tests to solve this issue. I would really like to try the GHDL LSP Server on Neovim.

[tgingold]

The ghdl executable looks correctly built and installed. But that's not the case for ghdl-ls.exe. It returns a weird prefix: /c/GHDL\lib\ghdl

[tgingold]

So I suppose you configured ghdl using `--prefix=/c/GHDL` You should try with a windows path: `--prefix=C:\\GHDL`

[pidgeon777]

Ok, I tried some combinations and this worked:

--prefix=C:/GHDL

I think the documentation should be updated too, where the prefix part is cited:

https://github.com/ghdl/ghdl

The executable is installed as 'ghdl' in /usr/local. To install it to a different path, change the --prefix in the call to configure. For example, on Windows, you may want to set it to --prefix=/c/Program Files (x86)/GHDL.

The great news is that I'm finally able to run ghdl-ls in Neovim, on my Windows machine.

Here is the new ghdl-ls --disp.config output:

command line prefix (--PREFIX): (not set)
environment prefix (GHDL_PREFIX): (not set)
exec prefix (from program name): C:\msys64\mingw64

library prefix: C:/GHDL\lib/ghdl
library directory: C:/GHDL\lib/ghdl

and ghdl-ls --version:

ghdl-ls 1.0.0rc3

Apparently and interestingly, it has been updated from 1.0-dev to 1.0.0rc3 in the last few hours.

I've already conducted some tests, should I open a new issue to discuss them?

In the meanwhile, my most sincere thanks for your help.

[eine]

@pidgeon777, on MSYS2, it should work without manually building GHDL:

pacman -S mingw-w64-ghdl-llvm mingw-w64-python-pip
pip install git+https://github.com/ghdl/ghdl.git@$(ghdl version hash)

You can open any other terminal/tool from there (cmd, powershell) for inheriting the environment.

That's how I use the VSCode extension.