proc/native/windows: do not call _DebugBreakProcess on a stopped process (#2140)

Fixes #2138

_fixtures/issue2138.go

@@ -0,0 +1,10 @@
+package main
+
+import (
+	"time"
+)
+
+func main() {
+	time.Sleep(time.Hour)
+	println("ok")
+}

pkg/proc/native/proc_windows.go

@@ -17,6 +17,7 @@ type osProcessDetails struct {
 	hProcess    syscall.Handle
 	breakThread int
 	entryPoint  uint64
+	running     bool
 }
 
 // Launch creates and begins debugging a new process.
@@ -175,6 +176,10 @@ func (dbp *nativeProcess) kill() error {
 }
 
 func (dbp *nativeProcess) requestManualStop() error {
+	if !dbp.os.running {
+		return nil
+	}
+	dbp.os.running = false
 	return _DebugBreakProcess(dbp.os.hProcess)
 }
 
@@ -390,6 +395,7 @@ func (dbp *nativeProcess) resume() error {
 			return err
 		}
 	}
+	dbp.os.running = true
 
 	return nil
 }
@@ -400,6 +406,8 @@ func (dbp *nativeProcess) stop(trapthread *nativeThread) (err error) {
 		return &proc.ErrProcessExited{Pid: dbp.Pid()}
 	}
 
+	dbp.os.running = false
+
 	// While the debug event that stopped the target was being propagated
 	// other target threads could generate other debug events.
 	// After this function we need to know about all the threads

pkg/proc/proc_test.go

@@ -4906,3 +4906,35 @@ func TestStepoutOneliner(t *testing.T) {
 		}
 	})
 }
+
+func TestRequestManualStopWhileStopped(t *testing.T) {
+	// Requesting a manual stop while stopped shouldn't cause problems (issue #2138).
+	withTestProcess("issue2138", t, func(p *proc.Target, fixture protest.Fixture) {
+		resumed := make(chan struct{})
+		setFileBreakpoint(p, t, fixture.Source, 8)
+		assertNoError(p.Continue(), t, "Continue() 1")
+		p.ResumeNotify(resumed)
+		go func() {
+			<-resumed
+			time.Sleep(1 * time.Second)
+			p.RequestManualStop()
+		}()
+		t.Logf("at time.Sleep call")
+		assertNoError(p.Continue(), t, "Continue() 2")
+		t.Logf("manually stopped")
+		p.RequestManualStop()
+		p.RequestManualStop()
+		p.RequestManualStop()
+
+		resumed = make(chan struct{})
+		p.ResumeNotify(resumed)
+		go func() {
+			<-resumed
+			time.Sleep(1 * time.Second)
+			p.RequestManualStop()
+		}()
+		t.Logf("resuming sleep")
+		assertNoError(p.Continue(), t, "Continue() 3")
+		t.Logf("done")
+	})
+}