Fix panic in metadata content writer on copy error

dmcgowan · dmcgowan · commit b9cf0d75a9f4 · 2021-09-23T10:29:52.000-07:00
The `createAndCopy` function is only called when `nw.w` is nil
in order to create a new writer and prepare it. The current code
is attempting to close `nw.w` when there is a copy error. The
correct behavior would be to close the new writer and not touch `nw.w`.

Signed-off-by: Derek McGowan &lt;derek@mcg.dev&gt;
diff --git a/metadata/content.go b/metadata/content.go
@@ -558,13 +558,13 @@ func (nw *namespacedWriter) createAndCopy(ctx context.Context, desc ocispec.Desc
 	if desc.Size > 0 {
 		ra, err := nw.provider.ReaderAt(ctx, nw.desc)
 		if err != nil {
+			w.Close()
 			return err
 		}
 		defer ra.Close()
 
 		if err := content.CopyReaderAt(w, ra, desc.Size); err != nil {
-			nw.w.Close()
-			nw.w = nil
+			w.Close()
 			return err
 		}
 	}

Original file line number	Diff line number	Diff line change
`@@ -558,13 +558,13 @@ func (nw *namespacedWriter) createAndCopy(ctx context.Context, desc ocispec.Desc`
`558`	`558`	`if desc.Size > 0 {`
`559`	`559`	`ra, err := nw.provider.ReaderAt(ctx, nw.desc)`
`560`	`560`	`if err != nil {`
	`561`	`+ w.Close()`
`561`	`562`	`return err`
`562`	`563`	`}`
`563`	`564`	`defer ra.Close()`
`564`	`565`
`565`	`566`	`if err := content.CopyReaderAt(w, ra, desc.Size); err != nil {`
`566`		`- nw.w.Close()`
`567`		`- nw.w = nil`
	`567`	`+ w.Close()`
`568`	`568`	`return err`
`569`	`569`	`}`
`570`	`570`	`}`