We probably need to update the README. We should at least to say what the 'language' parameter would be for extra conf.

I think this is neat. We could create a wiki page on the repo that says those servers known to work but are considered "unsupported" in the sense that we'll support with best-efforts only.

Thanks for doing this. It was always in the back of my mind to do something like this with LSP.

with minor comments.

Reviewed 9 of 9 files at r1.
Reviewable status: 1 of 2 LGTMs obtained (waiting on @bstaletic)

run_tests.py, line 322 at r1 (raw file):

  old_cwd = os.getcwd()
  os.chdir( os.path.join( DIR_OF_THIRD_PARTY, 'generic_server' ) )
  npm = FindExecutableOrDie( 'npm', 'npm is required to install TSServer.' )

We're not installing TSServer ?

run_tests.py, line 325 at r1 (raw file):

  with open( os.devnull, 'w' ) as devnull:
    subprocess.check_call( [ npm, 'install' ],
                           stdout = devnull,

what's the reason for this forced redirect ? If there are installation errors (e.g. proxy error or something), it will be tricky to debug. I'm not against the extra console output personally.

third_party/generic_server/out/server.js, line 4 at r1 (raw file):

/* --------------------------------------------------------------------------------------------
 * Copyright (c) Microsoft Corporation. All rights reserved.
 * Licensed under the MIT License. See License.txt in the project root for license information.

is this compatible with our GPL license ? Only asking because I haven't checked.

Out of interest, can we get this from npm too like we did with tern? I.e. just put it in as a dependency in package.json ?

ycmd/server_state.py, line 38 at r1 (raw file):

  if lsp_cmdline is not None:
    return generic_lsp_completer.GenericLSPCompleter(
        user_options, filetype, lsp_cmdline )

Any expectation that we might want to supply more than the command line here? e.g. should we tempt YAGNI and make it a dict like:

{
    "language_server": {
        "generic_ls": {
            "command_line": [ "thing", "here" ],
        }
    }
}

That would possibly allow us to add, say environment variables or something in future.

Reviewable status: 0 of 2 LGTMs obtained (and 1 stale) (waiting on @micbou and @puremourning)

run_tests.py, line 322 at r1 (raw file):

Done.

run_tests.py, line 325 at r1 (raw file):

I thought it was annoying to see it every time you run the tests, even if you don't intend to run these tests.

Anyway, redirection dropped.

third_party/generic_server/out/server.js, line 4 at r1 (raw file):

is this compatible with our GPL license ? Only asking because I haven't checked.

MIT license is GPL-compatible as far as I know.

Out of interest, can we get this from npm too like we did with tern? I.e. just put it in as a dependency in package.json ?

I don't know because I don't know how package.json. I mean I could write a simple package.json, but what do i put in "dependencies" list? I got the example server from here:

https://github.com/microsoft/vscode-extension-samples/tree/master/lsp-sample/server

ycmd/server_state.py, line 38 at r1 (raw file):

@micbou mentioned something similar in gitter. My argument was basically YAGNI and "support on best effort basis".

Reviewable status: 1 of 2 LGTMs obtained (waiting on @puremourning)

third_party/generic_server/out/server.js, line 4 at r1 (raw file):

I suppose we could just clone the whole thing with:

{
  "description": "Runtime area for LSP sample server",
  "dependencies": {
    "lsp-sample-server": "microsoft/vscode-extension-samples"
  }
}

But tbh this is probably fine. It allows us to fiddle with it anyway.

ycmd/server_state.py, line 38 at r1 (raw file):

Sure. We can always do if issuance (..., dict):

Reviewed 1 of 1 files at r2.
Reviewable status: 1 of 2 LGTMs obtained

Reviewable status: 1 of 2 LGTMs obtained

third_party/generic_server/out/server.js, line 4 at r1 (raw file):

The reason I put the actual source of the server in the repo was to avoid having microsoft/vscode-extension-samples a git submodule.

If you want me to, I can write the package.json and fix the paths. It would save a few MBs for the users.

Reviewable status: 1 of 2 LGTMs obtained

third_party/generic_server/out/server.js, line 4 at r1 (raw file):

Nah I think what you have is probably the best compromise. The whole repo is kinda large, and npm cloning it wasn't quick on my machine, so having a copy is fine. It also means that we can use this code to hack test scenarios if we want to. I'm cool with it.

Reviewed 3 of 3 files at r3.
Reviewable status: 1 of 2 LGTMs obtained

Updated with the changes requested in gitter.

This now supports servers that target multiple filetypes.

Reviewable status: 0 of 2 LGTMs obtained (and 1 stale) (waiting on @puremourning)

Thanks

Reviewed 5 of 5 files at r4.
Reviewable status: 1 of 2 LGTMs obtained

Finally! A green build!

Reviewable status: 0 of 2 LGTMs obtained (and 1 stale) (waiting on @puremourning)