From 3c527d146ed46daef0344041774486f50512dae2 Mon Sep 17 00:00:00 2001
From: Joshua Miller <jomiller@nvidia.com>
Date: Mon, 13 Jan 2025 12:05:52 -0800
Subject: [PATCH] [sdf] Fix Sdf_Children<ChildPolicy>::Find to return correct
 value

In most cases, Sdf_Children<ChildPolicy>::Find would return the incorrect value of 0 instead the size of _childNames.
This would incorrectly index into the first element when a matching element was not found
---
 pxr/usd/sdf/children.cpp           |  9 ++++-----
 pxr/usd/sdf/testenv/testSdfPrim.py | 25 +++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/pxr/usd/sdf/children.cpp b/pxr/usd/sdf/children.cpp
index 5370056366..4801b706af 100644
--- a/pxr/usd/sdf/children.cpp
+++ b/pxr/usd/sdf/children.cpp
@@ -86,19 +86,18 @@ size_t
 Sdf_Children<ChildPolicy>::Find(const KeyType &key) const
 {
     if (!TF_VERIFY(IsValid())) {
-        return 0;
+        return _childNames.size();
     }
 
     _UpdateChildNames();
 
     const FieldType expectedKey(_keyPolicy.Canonicalize(key));
-    size_t i = 0;
-    for (i=0; i < _childNames.size(); i++) {
+    for (size_t i=0; i < _childNames.size(); i++) {
         if (_childNames[i] == expectedKey) {
-            break;
+            return i;
         }
     }
-    return i;
+    return _childNames.size();
 }
 
 template<class ChildPolicy>
diff --git a/pxr/usd/sdf/testenv/testSdfPrim.py b/pxr/usd/sdf/testenv/testSdfPrim.py
index d071be5eae..789ebbc276 100644
--- a/pxr/usd/sdf/testenv/testSdfPrim.py
+++ b/pxr/usd/sdf/testenv/testSdfPrim.py
@@ -79,6 +79,31 @@ def test_NameChildrenInsert(self):
                 print("     previous list {0}".format(prevGroundTruthList))
                 self.fail("Prim insertion test failed")
 
+    def test_NameChildrenFind(self):
+        layer = Sdf.Layer.CreateAnonymous("test")
+        rootPrim = Sdf.PrimSpec(layer, 'Root', Sdf.SpecifierDef, 'Scope')
+
+        # find the index of a non-existent prim with no children
+        index = rootPrim.nameChildren.index('nonexistent')
+        self.assertEqual(index, -1)
+
+        # insert some child prims to find
+        for i in range(10):
+            primName = 'geom{0}'.format(i)
+            primSpec = Sdf.PrimSpec(layer, primName, Sdf.SpecifierDef, 'Scope')
+
+            rootPrim.nameChildren.insert(i, primSpec)
+
+        # find the index of the prims
+        for i in range(10):
+            primName = 'geom{0}'.format(i)
+            index = rootPrim.nameChildren.index(primName)
+            self.assertEqual(index, i)
+        
+        # find the index of a non-existent prim
+        index = rootPrim.nameChildren.index('nonexistent')
+        self.assertEqual(index, -1)
+
     def test_InertSpecRemoval(self):
         layer = Sdf.Layer.CreateAnonymous()