x/tools/gopls: didChangeConfiguration ignores the new configuration

[ainar-g]

I was trying to enable staticcheck using gopls version v0.5.0-pre1 and natebosch/vim-lsc, but couldn't. The plugin configuration was:

let g:lsc_server_commands = {
\   'go': {
\     'name': 'gopls',
\     'command': 'gopls serve',
\     'log_level': -1,
\     'suppress_stderr': v:true,
\     'workspace_config': {
\       'staticcheck': v:true,
\     },
\   },
\ }

I also used -rpc.trace and made sure that gopls actually receives the configuration with the workspace/didChangeConfiguration method. I inspected the code, and it seems like parameter changed of the server implementation is currently ignored:

func (s *Server) didChangeConfiguration(ctx context.Context, changed interface{}) error {
	// go through all the views getting the config
	for _, view := range s.session.Views() {
		options := view.Options()
		if err := s.fetchConfig(ctx, view.Name(), view.Folder(), &options); err != nil {
			return err
		}
		view, err := view.SetOptions(ctx, options)
		if err != nil {
			return err
		}
		go func() {
			snapshot, release := view.Snapshot(ctx)
			defer release()
			s.diagnoseDetached(snapshot)
		}()
	}
	return nil
}

If I enable stderr logging and add a log.Printf("%#v", changed) there, I can see, that the parameters are there:

[lsc:Error] StdErr from gopls: 2020/09/10 12:19:36 &protocol.DidChangeConfigurationParams{Settings:map[string]interface {}{"staticcheck":true}}

Is this a bug? Is there any additional information I should add?

[gopherbot]

Change https://golang.org/cl/254038 mentions this issue: internal/lsp: handle staticcheck in didChangeConfiguration

[ainar-g]

@stamblerre Thanks for looking into this so quickly! I applied the patch in the CL (patch set 5), but that didn't solve the issue. options.Staticcheck remains false before and after s.fetchConfig as well as at the end of updateAnalyzers, so no analysis is run. Am I missing something? (And is it better to leave such comments on the CL itself?)

[stamblerre]

Thanks for testing it out! It's fine/probably easier to leave comments here.
Do you see the second workspace/configuration method in the log when fetchConfig runs for the second time, and does it return "staticcheck": true? I only tested with VS Code, but it fixed the issue there.

[ainar-g]

@stamblerre Ah, I see what's wrong now. vim-lsc assumes, that the server just accepts the configuration that the client sent with didChangeConfiguration. It doesn't know or respond to configuration. I cobbled together a patch to vim-lsc that fixes that, and voilà, staticcheck works now. I'll send the patch to the maintainers of that client. Sorry for the noise!

[stamblerre]

Perfect--thanks for doing that! And definitely not noise - there was a gopls bug here too.

[gopherbot]

Change https://golang.org/cl/254427 mentions this issue: [gopls-release-branch.0.5] internal/lsp: handle staticcheck in didChangeConfiguration