Error on Registering Activity with Workflow Context (#1093)

internal/internal_worker.go

@@ -723,6 +723,15 @@ func validateFnFormat(fnType reflect.Type, isWorkflow bool) error {
 		if !isWorkflowContext(fnType.In(0)) {
 			return fmt.Errorf("expected first argument to be workflow.Context but found %s", fnType.In(0))
 		}
+	} else {
+		// For activities, check that workflow context is not accidentally provided
+		// Activities registered with structs will have their receiver as the first argument so confirm it is not
+		// in the first two arguments
+		for i := 0; i < fnType.NumIn() && i < 2; i++ {
+			if isWorkflowContext(fnType.In(i)) {
+				return fmt.Errorf("unexpected use of workflow context for an activity")
+			}
+		}
 	}
 
 	// Return values

internal/internal_worker_test.go

@@ -2252,6 +2252,37 @@ func TestRegisterStructWithInvalidFnsWithoutSkipFails(t *testing.T) {
 	assert.Panics(t, testRegisterStructWithInvalidFnsWithoutSkipFails)
 }
 
+type testActivityStructWithFnWithWorkflowContext struct{}
+
+func (t *testActivityStructWithFnWithWorkflowContext) InvalidActivity(Context) error {
+	return nil
+}
+
+func testRegisterStructWithInvalidWorkflowContextFnFails() {
+	registry := newRegistry()
+	registry.RegisterActivityWithOptions(&testActivityStructWithFnWithWorkflowContext{}, RegisterActivityOptions{
+		Name:                       "testActivityStructWithFnWithWorkflowContext_",
+		SkipInvalidStructFunctions: false,
+	})
+}
+
+func TestRegisterStructWithInvalidWorkflowContextFnFails(t *testing.T) {
+	assert.Panics(t, testRegisterStructWithInvalidWorkflowContextFnFails)
+}
+
+func InvalidActivityWithWorkflowContext(Context) error {
+	return nil
+}
+
+func testRegisterStructWithInvalidActivityWithWorkflowContextFails() {
+	registry := newRegistry()
+	registry.RegisterActivity(InvalidActivityWithWorkflowContext)
+}
+
+func TestRegisterStructWithInvalidActivityWithWorkflowContextFails(t *testing.T) {
+	assert.Panics(t, testRegisterStructWithInvalidActivityWithWorkflowContextFails)
+}
+
 func TestVariousActivitySchedulingOption(t *testing.T) {
 	w := &activitiesCallingOptionsWorkflow{t: t}