Handle nullable arrays (#283)

Fixes: #282

Author: karencfv

.changelog/v0.5.0.toml

@@ -7,8 +7,8 @@ title = ""
 description = ""
 
 [[bugs]]
-title = ""
-description = ""
+title = "Type fields"
+description = "All arrays that are nullable in the API no longer have `omitempty` to avoid panics if unset. [#283](https://github.com/oxidecomputer/oxide.go/pull/283)"
 
 [[enhancements]]
 title = ""

internal/generate/exceptions.go

@@ -4,24 +4,16 @@
 
 package main
 
-// Returns a list of types that should not be omitted when empty
-// for json serialisation
-func omitemptyExceptions() []string {
-	return []string{
-		"[]VpcFirewallRuleUpdate",
-		"[]NameOrId",
-	}
-}
-
 func emptyTypes() []string {
 	return []string{
 		"BgpMessageHistory",
 		"SwitchLinkState",
 	}
 }
 
-// TODO: Actually handle nullable fields properly
 func nullable() []string {
+	// TODO: This type has a nested required "Type" field, which hinders
+	// the usage of this type. Remove when this is fixed in the upstream API
 	return []string{
 		"InstanceDiskAttachment",
 	}

internal/generate/types.go

@@ -541,12 +541,12 @@ func createTypeObject(schema *openapi3.Schema, name, typeName, description strin
 
 		field.Name = strcase.ToCamel(k)
 		field.Type = typeName
+
 		serInfo := fmt.Sprintf("`json:\"%s,omitempty\" yaml:\"%s,omitempty\"`", k, k)
-		// There are a few types we do not want to omit if empty
-		// TODO: Keep an eye out to see if there is a way to identify all of
-		if sliceContains(omitemptyExceptions(), typeName) {
+		if isNullableArray(v) {
 			serInfo = fmt.Sprintf("`json:\"%s\" yaml:\"%s\"`", k, k)
 		}
+
 		field.SerializationInfo = serInfo
 
 		fields = append(fields, field)

internal/generate/utils.go

@@ -59,6 +59,10 @@ func isObjectArray(v *openapi3.SchemaRef) bool {
 	return false
 }
 
+func isNullableArray(v *openapi3.SchemaRef) bool {
+	return v.Value.Type.Is("array") && v.Value.Nullable
+}
+
 // formatStringType converts a string schema to a valid Go type.
 func formatStringType(t *openapi3.Schema) string {
 	var format string