fix(lsp): perform client side filtering of code actions (#18392)

Implement filtering of actions based on the kind when passing the 'only'
parameter to code_action(). Action kinds are hierachical with a '.' as
the separator, and the filter thus allows, for example, both 'quickfix'
and 'quickfix.foo' when requestiong only 'quickfix'.

Fix https://github.com/neovim/neovim/pull/18221#issuecomment-1110179121

runtime/lua/vim/lsp/buf.lua

@@ -691,10 +691,38 @@ end
 --- `codeAction/resolve`
 local function on_code_action_results(results, ctx, options)
   local action_tuples = {}
-  local filter = options and options.filter
+
+  ---@private
+  local function action_filter(a)
+    -- filter by specified action kind
+    if options and options.context and options.context.only then
+      if not a.kind then
+        return false
+      end
+      local found = false
+      for _, o in ipairs(options.context.only) do
+        -- action kinds are hierachical with . as a separator: when requesting only
+        -- 'quickfix' this filter allows both 'quickfix' and 'quickfix.foo', for example
+        if a.kind:find('^' .. o .. '$') or a.kind:find('^' .. o .. '%.') then
+          found = true
+          break
+        end
+      end
+      if not found then
+        return false
+      end
+    end
+    -- filter by user function
+    if options and options.filter and not options.filter(a) then
+      return false
+    end
+    -- no filter removed this action
+    return true
+  end
+
   for client_id, result in pairs(results) do
     for _, action in pairs(result.result or {}) do
-      if not filter or filter(action) then
+      if action_filter(action) then
         table.insert(action_tuples, { client_id, action })
       end
     end

test/functional/fixtures/fake-lsp-server.lua

@@ -766,8 +766,21 @@ function tests.code_action_filter()
         isPreferred = true,
         command = 'preferred_command',
       }
+      local quickfix_action = {
+        title = 'Action 3',
+        kind = 'quickfix',
+        command = 'quickfix_command',
+      }
+      local quickfix_foo_action = {
+        title = 'Action 4',
+        kind = 'quickfix.foo',
+        command = 'quickfix_foo_command',
+      }
       expect_request('textDocument/codeAction', function()
-        return nil, { action, preferred_action, }
+        return nil, { action, preferred_action, quickfix_action, quickfix_foo_action, }
+      end)
+      expect_request('textDocument/codeAction', function()
+        return nil, { action, preferred_action, quickfix_action, quickfix_foo_action, }
       end)
       notify('shutdown')
     end;

test/functional/plugin/lsp_spec.lua

@@ -2753,12 +2753,33 @@ describe('LSP', function()
                 vim.lsp.commands['executed_preferred'] = function()
                 end
               end
+              vim.lsp.commands['quickfix_command'] = function(cmd)
+                vim.lsp.commands['executed_quickfix'] = function()
+                end
+              end
               local bufnr = vim.api.nvim_get_current_buf()
               vim.lsp.buf_attach_client(bufnr, TEST_RPC_CLIENT_ID)
               vim.lsp.buf.code_action({ filter = function(a) return a.isPreferred end, apply = true, })
+              vim.lsp.buf.code_action({
+                  -- expect to be returned actions 'quickfix' and 'quickfix.foo'
+                  context = { only = {'quickfix'}, },
+                  apply = true,
+                  filter = function(a)
+                      if a.kind == 'quickfix.foo' then
+                        vim.lsp.commands['filtered_quickfix_foo'] = function() end
+                        return false
+                      elseif a.kind == 'quickfix' then
+                        return true
+                      else
+                        assert(nil, 'unreachable')
+                      end
+                  end,
+              })
             ]])
           elseif ctx.method == 'shutdown' then
             eq('function', exec_lua[[return type(vim.lsp.commands['executed_preferred'])]])
+            eq('function', exec_lua[[return type(vim.lsp.commands['filtered_quickfix_foo'])]])
+            eq('function', exec_lua[[return type(vim.lsp.commands['executed_quickfix'])]])
             client.stop()
           end
         end