Improve expr types, add r/w locking

pkg/wfexec/session.go

@@ -185,7 +185,7 @@ func NewSession(ctx context.Context, g *Graph, oo ...SessionOpt) *Session {
 	return s
 }
 
-func (s Session) Status() SessionStatus {
+func (s *Session) Status() SessionStatus {
 	s.mux.RLock()
 	defer s.mux.RUnlock()
 
@@ -207,14 +207,14 @@ func (s Session) Status() SessionStatus {
 	}
 }
 
-func (s Session) ID() uint64 {
+func (s *Session) ID() uint64 {
 	s.mux.RLock()
 	defer s.mux.RUnlock()
 
 	return s.id
 }
 
-func (s Session) Idle() bool {
+func (s *Session) Idle() bool {
 	return s.Status() != SessionActive
 }
 
@@ -514,7 +514,7 @@ func (s *Session) Stop() {
 	s.qErr <- nil
 }
 
-func (s Session) Suspended() bool {
+func (s *Session) Suspended() bool {
 	defer s.mux.RUnlock()
 	s.mux.RLock()
 	return len(s.delayed) > 0

pkg/wfexec/session_test.go

@@ -96,7 +96,7 @@ func TestSession_SplitAndMerge(t *testing.T) {
 		ctx = context.Background()
 		req = require.New(t)
 		wf  = NewGraph()
-		ses = NewSession(ctx, wf)
+		ses = NewSession(ctx, wf, SetDumpStacktraceOnPanic(true))
 
 		start  = &sesTestStep{name: "start"}
 		split1 = &sesTestStep{name: "split1"}