fix: closing stdout

pack client was closing stdout
this commit prevents that

Signed-off-by: Matej Vasek <mvasek@redhat.com>

buildpacks/builder.go

@@ -95,7 +95,9 @@ func (builder *Builder) Build(ctx context.Context, f fn.Function) (err error) {
 	// log output is either STDOUt or kept in a buffer to be printed on error.
 	var logWriter io.Writer
 	if builder.Verbose {
-		logWriter = os.Stdout
+		// pass stdout as non-closeable writer
+		// otherwise pack client would close it which is bad
+		logWriter = stdoutWrapper{os.Stdout}
 	} else {
 		logWriter = &bytes.Buffer{}
 	}
@@ -129,6 +131,15 @@ func (builder *Builder) Build(ctx context.Context, f fn.Function) (err error) {
 	return
 }
 
+// hack this makes stdout non-closeable
+type stdoutWrapper struct {
+	impl io.Writer
+}
+
+func (s stdoutWrapper) Write(p []byte) (n int, err error) {
+	return s.impl.Write(p)
+}
+
 type clientWrapper struct {
 	impl dockerClient.CommonAPIClient
 }

client_int_test.go

@@ -153,8 +153,6 @@ func TestRemove(t *testing.T) {
 // newClient creates an instance of the func client whose concrete impls
 // match those created by the kn func plugin CLI.
 func newClient(verbose bool) *boson.Client {
-	// TODO: Forcing verbose to false in order to pass integration tests
-	verbose = false
 	builder := buildpacks.NewBuilder()
 	builder.Verbose = verbose