From fd8c275b048291112793247e76bd9a50a6fc65e9 Mon Sep 17 00:00:00 2001
From: Georg Dangl <georg@dangl.me>
Date: Mon, 9 Oct 2023 10:44:15 +0200
Subject: [PATCH] Change README and visinfo to require topic files to be listed
 in viewpoints

---
 Documentation/README.md | 2 +-
 Schemas/visinfo.xsd     | 7 +++----
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/Documentation/README.md b/Documentation/README.md
index 3c3c708..e0a4528 100644
--- a/Documentation/README.md
+++ b/Documentation/README.md
@@ -223,7 +223,7 @@ The visualization information file contains information of components related to
 
 ### TopicFiles
 
-Parent topic objects specify a list of model files in their `Header.Files` element. These files contain an `Id` attribute, which can be used to optionally reference a subset of all the topic files for a specific viewpoint. If the viewpoint does contain entries in it's `TopicFiles` element, then only those files referenced there should be loaded when visualizing the viewpoint. Otherwise, all files from the topic should be loaded.
+Parent topic objects specify a list of model files in their `Header.Files` element. These files contain an `Id` attribute, which are used to reference a subset of all the topic files for a specific viewpoint. To make viewpoints immutable, e.g. in the case of later added topic files, each viewpoint is required to list all their file references. Only those files referenced In a viewpoints `TopicFiles` should be loaded when visualizing the viewpoint.
 
 ### Components
 
diff --git a/Schemas/visinfo.xsd b/Schemas/visinfo.xsd
index 8f070e6..8b3c579 100644
--- a/Schemas/visinfo.xsd
+++ b/Schemas/visinfo.xsd
@@ -7,9 +7,7 @@
         </xs:annotation>
         <xs:complexType>
             <xs:sequence>
-                <!-- If one or more TopicFile elements are present, then this means that the
-                viewpoint is only supposed to load the given file references. Otherwise, the files
-                to be loaded in the viewpoint are the same as the Files list in the parent topic.-->
+                <!-- The TopicFiles element lists the model files this viewpoint is supposed to load.-->
                 <xs:element name="TopicFiles" type="TopicFiles"/>
                 <!--
                 Although plural, 'Components' is not a collection
@@ -112,7 +110,8 @@
     </xs:simpleType>
     <xs:complexType name="TopicFiles">
         <xs:sequence>
-            <xs:element name="TopicFileId" type="TopicFileId" minOccurs="0" maxOccurs="unbounded"/>
+            <!-- A viewpoint needs to list it's referenced files, so at least one file must be present. -->
+            <xs:element name="TopicFileId" type="TopicFileId" maxOccurs="unbounded"/>
         </xs:sequence>
     </xs:complexType>
     <xs:complexType name="TopicFileId">