add support for window/showMessageRequest (#919)

* show message request
* materialize so doesn't throw error and add message to input list
* fix lint issues and rename flag to lsp_show_message_request_enabled
* use action and fix filter
* document g:lsp_show_message_request_enabled

Author: prabirshrestha

autoload/lsp.vim

@@ -66,6 +66,7 @@ function! lsp#enable() abort
     call lsp#ui#vim#completion#_setup()
     call lsp#internal#diagnostics#_enable()
     call lsp#internal#highlight_references#_enable()
+    call lsp#internal#show_message_request#_enable()
     call s:register_events()
 endfunction
 
@@ -81,6 +82,7 @@ function! lsp#disable() abort
     call lsp#ui#vim#completion#_disable()
     call lsp#internal#diagnostics#_disable()
     call lsp#internal#highlight_references#_disable()
+    call lsp#internal#show_message_request#_disable()
     call s:unregister_events()
     let s:enabled = 0
 endfunction
@@ -759,7 +761,7 @@ function! s:on_notification(server_name, id, data, event) abort
 endfunction
 
 function! s:on_request(server_name, id, request) abort
-    call lsp#log_verbose('<---', a:id, a:request)
+    call lsp#log_verbose('<---', 's:on_request', a:id, a:request)
 
     let l:stream_data = { 'server': a:server_name, 'request': a:request }
     call s:Stream(1, l:stream_data) " notify stream before callbacks

autoload/lsp/internal/show_message_request.vim

@@ -0,0 +1,58 @@
+function! lsp#internal#show_message_request#_enable() abort
+    if !g:lsp_show_message_request_enabled | return | endif
+    let s:Dispose = lsp#callbag#pipe(
+            \ lsp#stream(),
+            \ lsp#callbag#filter({x->
+            \   g:lsp_show_message_request_enabled &&
+            \   has_key(x, 'request') && !has_key(x, 'response') &&
+            \   has_key(x['request'], 'method') && x['request']['method'] ==# 'window/showMessageRequest'
+            \ }),
+            \ lsp#callbag#map({x->s:show_message_request(x['server'], x['request'])}),
+            \ lsp#callbag#map({x->s:send_message_response(x['server'], x['request'], x['action'])}),
+            \ lsp#callbag#flatten(),
+            \ lsp#callbag#materialize(),
+            \ lsp#callbag#subscribe({ 'error': function('s:on_error') }),
+            \ )
+endfunction
+
+function! lsp#internal#show_message_request#_disable() abort
+    if exists('s:Dispose')
+        call s:Dispose()
+        unlet s:Dispose
+    endif
+endfunction
+
+function! s:on_error(e) abort
+    call lsp#log('lsp#internal#show_message_request error', a:e)
+    if exists('s:Dispose')
+        call s:Dispose()
+        unlet s:Dispose
+    endif
+endfunction
+
+function! s:show_message_request(server_name, request) abort
+    let l:params = a:request['params']
+
+    let l:selected_action = v:null
+
+    if has_key(l:params, 'actions') && !empty(l:params['actions'])
+        let l:options = map(copy(l:params['actions']), {i, action ->
+            \   printf('%d - [%s] %s', i + 1, a:server_name, action['title'])
+            \ })
+        let l:index = inputlist([l:params['message']] + l:options)
+        if l:index > 0 && l:index <= len(l:index)
+            let l:selected_action = l:params['actions'][l:index - 1]
+        endif
+    else
+        echom l:params['message']
+    endif
+
+    return { 'server': a:server_name, 'request': a:request, 'action': l:selected_action }
+endfunction
+
+function! s:send_message_response(server_name, request, action) abort
+    return lsp#request(a:server_name, {
+        \ 'id': a:request['id'],
+        \ 'result': a:action
+        \})
+endfunction

doc/vim-lsp.txt

@@ -48,6 +48,7 @@ CONTENTS                                                  *vim-lsp-contents*
       g:lsp_snippet_expand                  |g:lsp_snippet_expand|
       g:lsp_completion_resolve_timeout      |g:lsp_completion_resolve_timeout|
       g:lsp_tagfunc_source_methods          |g:lsp_tagfunc_source_methods|
+      g:lsp_show_message_request_enabled    |g:lsp_show_message_request_enabled|
     Functions                             |vim-lsp-functions|
       lsp#enable                            |lsp#enable()|
       lsp#disable                           |lsp#disable()|
@@ -690,6 +691,13 @@ g:lsp_tagfunc_source_methods                 *g:lsp_tagfunc_source_methods*
     The LSP methods to call to get symbols for tag lookup. See
     |vim-lsp-tagfunc|.
 
+g:lsp_show_message_request_enabled         *g:lsp_show_message_request_enabled*
+    Type: |Number|
+    Default: `1`
+
+    Determines whether or not `window/showMessageRequest` should show message to
+    the user or if it should be ignored. Set to `1` to enable.
+
 ==============================================================================
 FUNCTIONS                                               *vim-lsp-functions*
 

plugin/lsp.vim

@@ -48,6 +48,7 @@ let g:lsp_semantic_enabled = get(g:, 'lsp_semantic_enabled', 0)
 let g:lsp_text_document_did_save_delay = get(g:, 'lsp_text_document_did_save_delay', -1)
 let g:lsp_completion_resolve_timeout = get(g:, 'lsp_completion_resolve_timeout', 200)
 let g:lsp_tagfunc_source_methods = get(g:, 'lsp_tagfunc_source_methods', ['definition', 'declaration', 'implementation', 'typeDefinition'])
+let g:lsp_show_message_request_enabled = get(g:, 'lsp_show_message_request_enabled', 1)
 
 let g:lsp_get_supported_capabilities = get(g:, 'lsp_get_supported_capabilities', [function('lsp#default_get_supported_capabilities')])