Update fetch handling

Fix issue where manifest content must always be fetched
even if it is already fully downloaded or shared locally.
Simplify children label setting and platform filtering.
Prevent getting a fetcher when content shared locally.

Signed-off-by: Derek McGowan <derek@mcgstyle.net>

client.go

@@ -234,10 +234,17 @@ func (c *Client) Pull(ctx context.Context, ref string, opts ...RemoteOpt) (Image
 		schema1Converter = schema1.NewConverter(store, fetcher)
 		handler = images.Handlers(append(pullCtx.BaseHandlers, schema1Converter)...)
 	} else {
+		// Get all the children for a descriptor
+		childrenHandler := images.ChildrenHandler(store)
+		// Set any children labels for that content
+		childrenHandler = images.SetChildrenLabels(store, childrenHandler)
+		// Filter the childen by the platform
+		childrenHandler = images.FilterPlatform(platforms.Default(), childrenHandler)
+
 		handler = images.Handlers(append(pullCtx.BaseHandlers,
 			remotes.FetchHandler(store, fetcher),
-			images.ChildrenHandler(store, platforms.Default()))...,
-		)
+			childrenHandler,
+		)...)
 	}
 
 	if err := images.Dispatch(ctx, handler, desc); err != nil {