test(lsp): fix fake LSP server timeout not working (#37970)

Problem:  Fake LSP server does not timeout or respond to SIGTERM as it
          does not run the event loop.
Solution: Instead of io.read(), use stdioopen()'s on_stdin callback to
          accumulate input and use vim.wait() to wait for input.

Also, in the test suite, don't stop a session when it's not running, as
calling uv.stop() outside uv.run() will instead cause the next uv.run()
to stop immediately, which cancels the next RPC request.

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

@@ -1,10 +1,22 @@
 local protocol = require 'vim.lsp.protocol'
 
+local pid = vim.uv.os_getpid()
+local stdin = ''
+vim.fn.stdioopen({
+  on_stdin = function(_, data, _)
+    stdin = stdin .. table.concat(data, '\n')
+  end,
+})
+
 -- Logs to $NVIM_LOG_FILE.
 --
 -- TODO(justinmk): remove after https://github.com/neovim/neovim/pull/7062
 local function log(loglevel, area, msg)
-  vim.fn.writefile({ string.format('%s %s: %s', loglevel, area, msg) }, vim.env.NVIM_LOG_FILE, 'a')
+  vim.fn.writefile(
+    { string.format('%d %s %s: %s', pid, loglevel, area, msg) },
+    vim.env.NVIM_LOG_FILE,
+    'a'
+  )
 end
 
 local function message_parts(sep, ...)
@@ -46,10 +58,30 @@ local function format_message_with_content_length(encoded_message)
   }
 end
 
+local function read_line()
+  vim.wait(math.huge, function()
+    return stdin:find('\n') ~= nil
+  end, 1)
+  local eol = assert(stdin:find('\n'))
+  local line = stdin:sub(1, eol - 1)
+  stdin = stdin:sub(eol + 1)
+  return line
+end
+
+--- @param len integer
+local function read_len(len)
+  vim.wait(math.huge, function()
+    return stdin:len() >= len
+  end, 1)
+  local content = stdin:sub(1, len)
+  stdin = stdin:sub(len + 1)
+  return content
+end
+
 local function read_message()
-  local line = io.read('*l')
+  local line = read_line()
   local length = line:lower():match('content%-length:%s*(%d+)')
-  return vim.json.decode(io.read(2 + length):sub(2))
+  return vim.json.decode(read_len(2 + length):sub(2))
 end
 
 local function send(payload)
@@ -1045,21 +1077,24 @@ end
 
 -- Tests will be indexed by test_name
 local test_name = arg[1]
-local timeout = arg[2]
+local timeout = tonumber(arg[2])
 assert(type(test_name) == 'string', 'test_name must be specified as first arg.')
 
-local kill_timer = assert(vim.uv.new_timer())
-kill_timer:start(timeout or 1e3, 0, function()
-  kill_timer:stop()
-  kill_timer:close()
+local kill_timer = vim.defer_fn(function()
   log('ERROR', 'LSP', 'TIMEOUT')
   io.stderr:write('TIMEOUT')
   os.exit(100)
-end)
+end, timeout or 1e3)
+
+-- Close the timer on exit (deadly signal or :cquit) to avoid delay with ASAN/TSAN.
+vim.api.nvim_create_autocmd('VimLeave', {
+  callback = function()
+    kill_timer:stop()
+    kill_timer:close()
+  end,
+})
 
 local status, err = pcall(assert(tests[test_name], 'Test not found'))
-kill_timer:stop()
-kill_timer:close()
 if not status then
   log('ERROR', 'LSP', tostring(err))
   io.stderr:write(err)

test/functional/plugin/lsp/testutil.lua

@@ -110,6 +110,7 @@ M.create_server_definition = function()
 
       function srv.terminate()
         closing = true
+        dispatchers.on_exit(0, 15)
       end
 
       return srv

test/functional/plugin/lsp_spec.lua

@@ -88,7 +88,11 @@ describe('LSP', function()
 
   after_each(function()
     stop()
-    exec_lua('vim.iter(lsp.get_clients()):each(function(client) client:stop(true) end)')
+    exec_lua(function()
+      vim.iter(vim.lsp.get_clients({ _uninitialized = true })):each(function(client)
+        client:stop(true)
+      end)
+    end)
     api.nvim_exec_autocmds('VimLeavePre', { modeline = false })
   end)
 
@@ -206,18 +210,18 @@ describe('LSP', function()
     it('does not reuse an already-stopping client #33616', function()
       -- we immediately try to start a second client with the same name/root
       -- before the first one has finished shutting down; we must get a new id.
-      local clients = exec_lua([[
-        local client1 = vim.lsp.start({
+      local clients = exec_lua(function()
+        local client1 = assert(vim.lsp.start({
           name = 'dup-test',
           cmd = { vim.v.progpath, '-l', fake_lsp_code, 'basic_init' },
-        }, { attach = false })
+        }, { attach = false }))
         vim.lsp.get_client_by_id(client1):stop()
-        local client2 = vim.lsp.start({
+        local client2 = assert(vim.lsp.start({
           name = 'dup-test',
           cmd = { vim.v.progpath, '-l', fake_lsp_code, 'basic_init' },
-        }, { attach = false })
+        }, { attach = false }))
         return { client1, client2 }
-        ]])
+      end)
       local c1, c2 = clients[1], clients[2]
       eq(false, c1 == c2, 'Expected a fresh client while the old one is stopping')
     end)
@@ -320,14 +324,8 @@ describe('LSP', function()
     )
 
     it('should succeed with manual shutdown', function()
-      if is_ci() then
-        pending('hangs the build on CI #14028, re-enable with freeze timeout #14204')
-        return
-      elseif t.skip_fragile(pending) then
-        return
-      end
       local expected_handlers = {
-        { NIL, {}, { method = 'shutdown', bufnr = 1, client_id = 1, version = 0 } },
+        { NIL, {}, { method = 'shutdown', bufnr = 1, client_id = 1, request_id = 2, version = 0 } },
         { NIL, {}, { method = 'test', client_id = 1 } },
       }
       test_rpc_server {

test/functional/testnvim.lua

@@ -320,7 +320,9 @@ function M.run(request_cb, notification_cb, setup_cb, timeout)
 end
 
 function M.stop()
-  assert(session):stop()
+  if loop_running then
+    assert(session):stop()
+  end
 end
 
 -- Use for commands which expect nvim to quit.