From 55172af7ba1e902080dbcd0cb469ae3c58bd8f22 Mon Sep 17 00:00:00 2001
From: Galen Suen <tiscs@live.com>
Date: Wed, 1 Nov 2023 00:49:02 +0000
Subject: [PATCH] Returns an existing Scope with the same name

---
 scope.go      | 15 ++++++++++++++-
 scope_test.go | 15 +++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/scope.go b/scope.go
index dc0c7ac5..53c3dccb 100644
--- a/scope.go
+++ b/scope.go
@@ -107,12 +107,25 @@ func newScope() *Scope {
 	return s
 }
 
-// Scope creates a new Scope with the given name and options from current Scope.
+// Scope creates a new Scope with the given name and options from current Scope,
+// or returns an existing Scope with the same name.
 // Any constructors that the current Scope knows about, as well as any modifications
 // made to it in the future will be propagated to the child scope.
 // However, no modifications made to the child scope being created will be propagated
 // to the parent Scope.
 func (s *Scope) Scope(name string, opts ...ScopeOption) *Scope {
+	// Check if a child scope with the same name already exists.
+	for _, s := range s.childScopes {
+		if s.name == name {
+			// in future, we may want to allow users to override options
+			for _, opt := range opts {
+				opt.noScopeOption()
+			}
+			return s
+		}
+	}
+
+	// otherwise, create a new child scope.
 	child := newScope()
 	child.name = name
 	child.parentScope = s
diff --git a/scope_test.go b/scope_test.go
index ff5db69d..40a22ae1 100644
--- a/scope_test.go
+++ b/scope_test.go
@@ -172,6 +172,21 @@ func TestScopedOperations(t *testing.T) {
 
 		child.RequireInvoke(func(T2) {})
 	})
+
+	t.Run("return existing scope if it already exists", func(t *testing.T) {
+		type A struct{}
+		type B struct{}
+
+		c := digtest.New(t)
+		s := c.Scope("child")
+		s.RequireProvide(func() *A { return &A{} })
+		s.RequireProvide(func() *B { return &B{} })
+
+		// Reuse the existing child scope.
+		s2 := c.Scope("child")
+		s2.RequireInvoke(func(*A) {})
+		s2.RequireInvoke(func(*B) {})
+	})
 }
 
 func TestScopeFailures(t *testing.T) {