Fix crash reading 2.8 files with workspace.view_layer set

Stupid error from e8c15e0ed1.

Also removed WorkSpace.view_layer usage and marked as deprecated.

source/blender/blenkernel/intern/workspace.c

@@ -445,7 +445,6 @@ ViewLayer *BKE_workspace_view_layer_get(const WorkSpace *workspace, const Scene
 }
 void BKE_workspace_view_layer_set(WorkSpace *workspace, ViewLayer *layer, Scene *scene)
 {
-	workspace->view_layer = layer;
 	workspace_relation_ensure_updated(&workspace->scene_viewlayer_relations, scene, layer);
 }
 

source/blender/blenloader/intern/readfile.c

@@ -6188,6 +6188,14 @@ static void direct_link_workspace_link_scene_data(
 				relation->value = layer;
 			}
 		}
+
+		if (workspace->view_layer) { /* this was temporariliy used during 2.8 project. Keep files compatible */
+			ViewLayer *layer = newdataadr(fd, workspace->view_layer);
+			/* only set when layer is from the scene we read */
+			if (layer && (BLI_findindex(&scene->view_layers, layer) != -1)) {
+				workspace->view_layer = layer;
+			}
+		}
 	}
 }
 

source/blender/blenloader/intern/versioning_280.c

@@ -549,6 +549,22 @@ void do_versions_after_linking_280(Main *main)
 		}
 	}
 
+	if (!MAIN_VERSION_ATLEAST(main, 280, 3)) {
+		for (WorkSpace *workspace = main->workspaces.first; workspace; workspace = workspace->id.next) {
+			if (workspace->view_layer) {
+				/* During 2.8 work we temporarly stored view-layer in the
+				 * workspace directly, but should be stored there per-scene. */
+				for (Scene *scene = main->scene.first; scene; scene = scene->id.next) {
+					if (BLI_findindex(&scene->view_layers, workspace->view_layer) > -1) {
+						BKE_workspace_view_layer_set(workspace, workspace->view_layer, scene);
+						workspace->view_layer = NULL;
+					}
+				}
+			}
+			BLI_assert(workspace->view_layer == NULL);
+		}
+	}
+
 	{
 		/* Since we don't have access to FileData we check the (always valid) master collection of the group. */
 		for (Group *group = main->group.first; group; group = group->id.next) {

source/blender/makesdna/DNA_workspace_types.h

@@ -95,7 +95,7 @@ typedef struct WorkSpace {
 	/* should be: '#ifdef USE_WORKSPACE_TOOL'. */
 	bToolDef tool;
 
-	struct ViewLayer *view_layer DNA_PRIVATE_WORKSPACE;
+	struct ViewLayer *view_layer DNA_DEPRECATED;
 	struct ViewRender view_render;
 } WorkSpace;