Weldr/ComposeRequest: OSTree options nil if not set

Previously, the `OSTree` property in the Weldr API `ComposeRequest`
struct was not a pointer to the `ostree.ImageOptions` type. As a result,
it was initialized to an empty struct, even if not set in the client API
call.

As a result, the `OSTree` property in the `distro.ImageOptions` was
always not `nil`, when initializing the osbuild manifest. However, after
a change in `osbuild/images` [0], providing OSTree options for
non-OSTree image types is no longer considered valid. This caused a
failure to submit a new compose for any non-OSTree image type.

Change the `OSTree` property in Weldr `ComposeRequest` to be a pointer
and mark it as optional.

[0] osbuild/images#1071

Signed-off-by: Tomáš Hozza <[email protected]>

internal/weldr/api.go

@@ -2415,12 +2415,12 @@ func (api *API) composeHandler(writer http.ResponseWriter, request *http.Request
 
 	// https://weldr.io/lorax/pylorax.api.html#pylorax.api.v0.v0_compose_start
 	type ComposeRequest struct {
-		BlueprintName string              `json:"blueprint_name"`
-		ComposeType   string              `json:"compose_type"`
-		Size          uint64              `json:"size"`
-		OSTree        ostree.ImageOptions `json:"ostree"`
-		Branch        string              `json:"branch"`
-		Upload        *uploadRequest      `json:"upload"`
+		BlueprintName string               `json:"blueprint_name"`
+		ComposeType   string               `json:"compose_type"`
+		Size          uint64               `json:"size"`
+		OSTree        *ostree.ImageOptions `json:"ostree,omitempty"`
+		Branch        string               `json:"branch"`
+		Upload        *uploadRequest       `json:"upload"`
 	}
 	type ComposeReply struct {
 		BuildID  uuid.UUID `json:"build_id"`
@@ -2549,7 +2549,7 @@ func (api *API) composeHandler(writer http.ResponseWriter, request *http.Request
 
 	options := distro.ImageOptions{
 		Size:             size,
-		OSTree:           &cr.OSTree,
+		OSTree:           cr.OSTree,
 		PartitioningMode: pm,
 	}
 	options.Facts = &facts.ImageOptions{