Close #4458 - Add an ALEStopLSP command

Add an ALEStopLSP command to stop all language servers that match a
given name. Completions are available for the command. This makes it
possible to keep other language servers running other than the one
you're interested in stopping.

autoload/ale/lsp/reset.vim

@@ -1,9 +1,16 @@
+" Author: w0rp <dev@w0rp.com>
+" Description: Functions for resetting LSP servers.
+
+function! s:Message(message) abort
+    call ale#util#Execute('echom ' . string(a:message))
+endfunction
+
 " Stop all LSPs and remove all of the data for them.
 function! ale#lsp#reset#StopAllLSPs() abort
     call ale#lsp#StopAll()
 
     if exists('*ale#definition#ClearLSPData')
-        " Clear the mapping for connections, etc.
+        " Clear the go to definition mapping for everything.
         call ale#definition#ClearLSPData()
     endif
 
@@ -25,3 +32,61 @@ function! ale#lsp#reset#StopAllLSPs() abort
         endfor
     endif
 endfunction
+
+function! ale#lsp#reset#Complete(arg, line, pos) abort
+    let l:linter_map = ale#lsp_linter#GetLSPLinterMap()
+    let l:candidates = map(values(l:linter_map), {_, linter -> linter.name})
+    call uniq(sort(l:candidates))
+    call filter(l:candidates, {_, name -> name =~? a:arg})
+
+    return l:candidates
+endfunction
+
+function! ale#lsp#reset#StopLSP(name, bang) abort
+    let l:linter_map = ale#lsp_linter#GetLSPLinterMap()
+    let l:matched = filter(
+    \   items(l:linter_map),
+    \   {_, item -> item[1].name is# a:name}
+    \)
+
+    if empty(l:matched)
+        if a:bang isnot# '!'
+            call s:Message('No running language server with name: ' . a:name)
+        endif
+
+        return
+    endif
+
+    " Stop LSP connections first.
+    for [l:conn_id, l:linter] in l:matched
+        call ale#lsp#Stop(l:conn_id)
+    endfor
+
+    if exists('*ale#definition#ClearLSPData')
+        " Clear the go to definition mapping for everything.
+        call ale#definition#ClearLSPData()
+    endif
+
+    " Remove connections from the lsp_linter map.
+    for [l:conn_id, l:linter] in l:matched
+        call remove(l:linter_map, l:conn_id)
+    endfor
+
+    " Remove the problems for the LSP linters in every buffer.
+    for [l:buffer_string, l:info] in items(g:ale_buffer_info)
+        let l:buffer = str2nr(l:buffer_string)
+        let l:should_clear_buffer = 0
+
+        for l:item in l:info.loclist
+            if l:item.linter_name is# a:name
+                let l:should_clear_buffer = 1
+
+                break
+            endif
+        endfor
+
+        if l:should_clear_buffer
+            call ale#engine#HandleLoclist(a:name, l:buffer, [], 0)
+        endif
+    endfor
+endfunction

autoload/ale/lsp_linter.vim

@@ -8,13 +8,9 @@ if !has_key(s:, 'lsp_linter_map')
     let s:lsp_linter_map = {}
 endif
 
-" A Dictionary to track one-shot handlers for custom LSP requests
-let s:custom_handlers_map = get(s:, 'custom_handlers_map', {})
-
 " Clear LSP linter data for the linting engine.
 function! ale#lsp_linter#ClearLSPData() abort
     let s:lsp_linter_map = {}
-    let s:custom_handlers_map = {}
 endfunction
 
 " Only for internal use.
@@ -82,7 +78,12 @@ function! s:ShouldIgnoreDiagnostics(buffer, linter) abort
 endfunction
 
 function! s:HandleLSPDiagnostics(conn_id, response) abort
-    let l:linter = s:lsp_linter_map[a:conn_id]
+    let l:linter = get(s:lsp_linter_map, a:conn_id)
+
+    if empty(l:linter)
+        return
+    endif
+
     let l:filename = ale#util#ToResource(a:response.params.uri)
     let l:escaped_name = escape(
     \   fnameescape(l:filename),
@@ -540,9 +541,14 @@ endfunction
 
 function! s:HandleLSPResponseToCustomRequests(conn_id, response) abort
     if has_key(a:response, 'id')
-    \&& has_key(s:custom_handlers_map, a:response.id)
-        let l:Handler = remove(s:custom_handlers_map, a:response.id)
-        call l:Handler(a:response)
+        " Get the custom handlers Dictionary from the linter map.
+        let l:linter = get(s:lsp_linter_map, a:conn_id, {})
+        let l:custom_handlers = get(l:linter, 'custom_handlers', {})
+
+        if has_key(l:custom_handlers, a:response.id)
+            let l:Handler = remove(l:custom_handlers, a:response.id)
+            call l:Handler(a:response)
+        endif
     endif
 endfunction
 
@@ -553,7 +559,17 @@ function! s:OnReadyForCustomRequests(args, linter, lsp_details) abort
     if l:request_id > 0 && has_key(a:args, 'handler')
         let l:Callback = function('s:HandleLSPResponseToCustomRequests')
         call ale#lsp#RegisterCallback(l:id, l:Callback)
-        let s:custom_handlers_map[l:request_id] = a:args.handler
+
+        " Remember the linter this connection is for.
+        let s:lsp_linter_map[l:id] = a:linter
+
+        " Add custom_handlers to the linter Dictionary.
+        if !has_key(a:linter, 'custom_handlers')
+            let a:linter.custom_handlers = {}
+        endif
+
+        " Put the handler function in the map to call later.
+        let a:linter.custom_handlers[l:request_id] = a:args.handler
     endif
 endfunction