test: wait for transition goroutines to exit

TestTransitionThreadsWhileDoingRequests spawned transition goroutines
that read mainThread.state via thread.shutdown(). isDone.Store(true)
signalled them to stop but the test returned without waiting, so they
could still be running when the next test's initPHPThreads wrote a
fresh mainThread.state, producing a -race failure on macOS.

Author: dunglas

phpmainthread_test.go

@@ -95,8 +95,9 @@ func TestTransitionThreadsWhileDoingRequests(t *testing.T) {
 	t.Cleanup(Shutdown)
 
 	var (
-		isDone atomic.Bool
-		wg     sync.WaitGroup
+		isDone        atomic.Bool
+		wg            sync.WaitGroup
+		transitionsWG sync.WaitGroup
 	)
 
 	numThreads := 10
@@ -122,8 +123,10 @@ func TestTransitionThreadsWhileDoingRequests(t *testing.T) {
 
 	// try all possible permutations of transition, transition every ms
 	transitions := allPossibleTransitions(worker1Path, worker2Path)
+	transitionsWG.Add(numThreads)
 	for i := range numThreads {
 		go func(thread *phpThread, start int) {
+			defer transitionsWG.Done()
 			for {
 				for j := start; j < len(transitions); j++ {
 					if isDone.Load() {
@@ -158,6 +161,9 @@ func TestTransitionThreadsWhileDoingRequests(t *testing.T) {
 	// we are finished as soon as all 1000 requests are done
 	wg.Wait()
 	isDone.Store(true)
+	// wait for transition goroutines to exit before Shutdown to avoid them
+	// racing with a subsequent test's initPHPThreads via mainThread.state
+	transitionsWG.Wait()
 }
 
 func TestFinishBootingAWorkerScript(t *testing.T) {