merge preconditions

taskfile/ast/precondition.go

@@ -40,6 +40,20 @@ func (p *Preconditions) DeepCopy() *Preconditions {
 	}
 }
 
+func (p *Preconditions) Merge(other *Preconditions) {
+	if p == nil || p.Preconditions == nil || other == nil {
+		return
+	}
+
+	p.mutex.Lock()
+	defer p.mutex.Unlock()
+
+	other.mutex.RLock()
+	defer other.mutex.RUnlock()
+
+	p.Preconditions = append(p.Preconditions, deepcopy.Slice(other.Preconditions)...)
+}
+
 func (p *Precondition) DeepCopy() *Precondition {
 	if p == nil {
 		return nil

taskfile/ast/taskfile.go

@@ -65,7 +65,7 @@ func (t1 *Taskfile) Merge(t2 *Taskfile, include *Include) error {
 	}
 	t1.Vars.Merge(t2.Vars, include)
 	t1.Env.Merge(t2.Env, include)
-	// TODO:@vmaerten Merge precondition
+	t1.Preconditions.Merge(t2.Preconditions)
 	return t1.Tasks.Merge(t2.Tasks, include, t1.Vars)
 }