refactor contexts code

pkg/gui/context/parent_context_mgr.go

@@ -0,0 +1,20 @@
+package context
+
+import "github.com/jesseduffield/lazygit/pkg/gui/types"
+
+type ParentContextMgr struct {
+	ParentContext types.Context
+	// we can't know on the calling end whether a Context is actually a nil value without reflection, so we're storing this flag here to tell us. There has got to be a better way around this
+	hasParent bool
+}
+
+var _ types.ParentContexter = (*ParentContextMgr)(nil)
+
+func (self *ParentContextMgr) SetParentContext(context types.Context) {
+	self.ParentContext = context
+	self.hasParent = true
+}
+
+func (self *ParentContextMgr) GetParentContext() (types.Context, bool) {
+	return self.ParentContext, self.hasParent
+}