Make the behavior of TypedStore.Update match the described behavior in the godoc (#604)

Make the behavior of `TypedStore.Update` match the described behavior in
the godoc with respect to ResourceVersion. If the ResourceVersion is
empty, return an error, and otherwise always pass the ResourceVersion to
the underlying UpdateOptions.

Duplicate of #595 applied
to the LTS branch.

Author: IfSentient

resource/typedstore.go

@@ -8,6 +8,8 @@ import (
 	"time"
 )
 
+var ErrMissingResourceVersion = fmt.Errorf("object is missing a ResourceVersion")
+
 // TypedStore is a single-Schema store where returned Objects from the underlying client are assumed
 // to be of ObjectType. It is a thin convenience layer over using a raw ClientGenerator.ClientFor()-created
 // Client for a Schema and doing type conversions in-code.
@@ -91,7 +93,13 @@ func (t *TypedStore[T]) Update(ctx context.Context, identifier Identifier, obj T
 	md := obj.GetCommonMetadata()
 	md.UpdateTimestamp = time.Now().UTC()
 	obj.SetCommonMetadata(md)
-	ret, err := t.client.Update(ctx, identifier, obj, UpdateOptions{})
+	if obj.GetResourceVersion() == "" {
+		var n T
+		return n, ErrMissingResourceVersion
+	}
+	ret, err := t.client.Update(ctx, identifier, obj, UpdateOptions{
+		ResourceVersion: obj.GetResourceVersion(),
+	})
 	if err != nil {
 		var n T
 		return n, err

resource/typedstore_test.go

@@ -161,13 +161,25 @@ func TestTypedStore_Update(t *testing.T) {
 		assert.Equal(t, cerr, err)
 	})
 
+	t.Run("no ResourceVersion", func(t *testing.T) {
+		client.UpdateFunc = func(ctx context.Context, identifier Identifier, obj Object, options UpdateOptions) (Object, error) {
+			assert.Fail(t, "client update should not be called")
+			return nil, nil
+		}
+		obj := updateObj.Copy().(*TypedSpecStatusObject[string, string])
+		obj.SetResourceVersion("")
+		ret, err := store.Update(ctx, id, obj)
+		assert.Nil(t, ret)
+		assert.Equal(t, ErrMissingResourceVersion, err)
+	})
+
 	t.Run("success, no metadata options", func(t *testing.T) {
 		client.UpdateFunc = func(c context.Context, identifier Identifier, obj Object, options UpdateOptions) (Object, error) {
 			assert.Equal(t, ctx, c)
 			assert.Equal(t, updateObj.Name, identifier.Name)
 			assert.Equal(t, updateObj.Namespace, identifier.Namespace)
 			assert.Equal(t, updateObj, obj)
-			assert.Equal(t, "", options.ResourceVersion)
+			assert.Equal(t, updateObj.ResourceVersion, options.ResourceVersion)
 			assert.Equal(t, "", options.Subresource)
 			return retObj, nil
 		}