[backport release-0.9] backport #25464 (#25560)

feat(lsp): fallback to code-action command on resolve failure

runtime/lua/vim/lsp/buf.lua

@@ -679,7 +679,7 @@ local function on_code_action_results(results, ctx, options)
     --  command: string
     --  arguments?: any[]
     --
-    local client = vim.lsp.get_client_by_id(action_tuple[1])
+    local client = assert(vim.lsp.get_client_by_id(action_tuple[1]))
     local action = action_tuple[2]
     if
       not action.edit
@@ -688,10 +688,14 @@ local function on_code_action_results(results, ctx, options)
     then
       client.request('codeAction/resolve', action, function(err, resolved_action)
         if err then
-          vim.notify(err.code .. ': ' .. err.message, vim.log.levels.ERROR)
+          if action.command then
-          return
+            apply_action(action, client)
+          else
+            vim.notify(err.code .. ': ' .. err.message, vim.log.levels.ERROR)
+          end
+        else
+          apply_action(resolved_action, client)
         end
-        apply_action(resolved_action, client)
       end)
     else
       apply_action(action, client)

test/functional/plugin/lsp_spec.lua

@@ -3309,6 +3309,48 @@ describe('LSP', function()
         end
       }
     end)
+    it("Fallback to command execution on resolve error", function()
+      clear()
+      exec_lua(create_server_definition)
+      local result = exec_lua([[
+        local server = _create_server({
+          capabilities = {
+            executeCommandProvider = {
+              commands = {"command:1"},
+            },
+            codeActionProvider = {
+              resolveProvider = true
+            }
+          },
+          handlers = {
+            ["textDocument/codeAction"] = function()
+              return {
+                {
+                  title = "Code Action 1",
+                  command = {
+                    title = "Command 1",
+                    command = "command:1",
+                  }
+                }
+              }
+            end,
+            ["codeAction/resolve"] = function()
+              return nil, "resolve failed"
+            end,
+          }
+        })
+        local client_id = vim.lsp.start({
+          name = "dummy",
+          cmd = server.cmd,
+        })
+        vim.lsp.buf.code_action({ apply = true })
+        vim.lsp.stop_client(client_id)
+        return server.messages
+      ]])
+      eq("codeAction/resolve", result[4].method)
+      eq("workspace/executeCommand", result[5].method)
+      eq("command:1", result[5].params.command)
+    end)
   end)
   describe('vim.lsp.commands', function()
     it('Accepts only string keys', function()