Icon/Render Preview: Fix Race condition with BKE_*_localize

When editing a Material the depsgraph can throw away the evaluated ID
before the preview job localized the said ID.

To fix this we localize the ID from the main thread.

Also fix WM_OT_previews_ensure crashing because of no depsgraph.

1 files changed, 72 insertions, 14 deletions

diff --git a/source/blender/editors/render/render_preview.c b/source/blender/editors/render/render_preview.c
index 04632838cf3..6ced3f2e430 100644
--- a/source/blender/editors/render/render_preview.c
+++ b/source/blender/editors/render/render_preview.c
@@ -158,7 +158,7 @@ typedef struct ShaderPreview {
 
 	Scene *scene;
 	Depsgraph *depsgraph;
-	ID *id;
+	ID *id, *id_copy;
 	ID *parent;
 	MTex *slot;
 
@@ -189,7 +189,7 @@ typedef struct IconPreview {
 	Scene *scene;
 	Depsgraph *depsgraph;
 	void *owner;
-	ID *id;
+	ID *id, *id_copy;
 	ListBase sizes;
 } IconPreview;
 
@@ -312,6 +312,29 @@ static World *preview_get_localized_world(ShaderPreview *sp, World *world)
 	return sp->worldcopy;
 }
 
+static ID *duplicate_ids(ID *id, Depsgraph *depsgraph)
+{
+	ID *id_eval = id;
+
+	if (depsgraph) {
+		id_eval = DEG_get_evaluated_id(depsgraph, id);
+	}
+
+	switch (GS(id->name)) {
+		case ID_MA:
+			return (ID *)BKE_material_localize((Material *)id_eval);
+		case ID_TE:
+			return (ID *)BKE_texture_localize((Tex *)id_eval);
+		case ID_LA:
+			return (ID *)BKE_lamp_localize((Lamp *)id_eval);
+		case ID_WO:
+			return (ID *)BKE_world_localize((World *)id_eval);
+		default:
+			BLI_assert(!"ID type preview not supported.");
+			return NULL;
+	}
+}
+
 /* call this with a pointer to initialize preview scene */
 /* call this with NULL to restore assigned ID pointers in preview scene */
 static Scene *preview_prepare_scene(Main *bmain, Scene *scene, ID *id, int id_type, ShaderPreview *sp)
@@ -373,8 +396,9 @@ static Scene *preview_prepare_scene(Main *bmain, Scene *scene, ID *id, int id_ty
 
 			if (origmat) {
 				/* work on a copy */
-				mat = BKE_material_localize(origmat);
-				sp->matcopy = mat;
+				BLI_assert(sp->id_copy != NULL);
+				mat = sp->matcopy = (Material *)sp->id_copy;
+				sp->id_copy = NULL;
 				BLI_addtail(&pr_main->mat, mat);
 
 				/* use current scene world to light sphere */
@@ -400,13 +424,13 @@ static Scene *preview_prepare_scene(Main *bmain, Scene *scene, ID *id, int id_ty
 					if (mat->nodetree && sp->pr_method == PR_NODE_RENDER) {
 						/* two previews, they get copied by wmJob */
 						BKE_node_preview_init_tree(mat->nodetree, sp->sizex, sp->sizey, true);
+						/* WATCH: Accessing origmat is not safe! */
 						BKE_node_preview_init_tree(origmat->nodetree, sp->sizex, sp->sizey, true);
 					}
 				}
 			}
 			else {
 				sce->r.mode &= ~(R_OSA);
-
 			}
 
 			for (Base *base = view_layer->object_bases.first; base; base = base->next) {
@@ -432,16 +456,18 @@ static Scene *preview_prepare_scene(Main *bmain, Scene *scene, ID *id, int id_ty
 			Tex *tex = NULL, *origtex = (Tex *)id;
 
 			if (origtex) {
-				tex = BKE_texture_localize(origtex);
-				sp->texcopy = tex;
+				BLI_assert(sp->id_copy != NULL);
+				tex = sp->texcopy = (Tex *)sp->id_copy;
+				sp->id_copy = NULL;
 				BLI_addtail(&pr_main->tex, tex);
 			}
 			set_preview_collection(sce, view_layer, MA_TEXTURE);
 
 			if (tex && tex->nodetree && sp->pr_method == PR_NODE_RENDER) {
 				/* two previews, they get copied by wmJob */
-				BKE_node_preview_init_tree(origtex->nodetree, sp->sizex, sp->sizey, true);
 				BKE_node_preview_init_tree(tex->nodetree, sp->sizex, sp->sizey, true);
+				/* WATCH: Accessing origtex is not safe! */
+				BKE_node_preview_init_tree(origtex->nodetree, sp->sizex, sp->sizey, true);
 			}
 		}
 		else if (id_type == ID_LA) {
@@ -449,8 +475,9 @@ static Scene *preview_prepare_scene(Main *bmain, Scene *scene, ID *id, int id_ty
 
 			/* work on a copy */
 			if (origla) {
-				la = BKE_lamp_localize(origla);
-				sp->lampcopy = la;
+				BLI_assert(sp->id_copy != NULL);
+				la = sp->lampcopy = (Lamp *)sp->id_copy;
+				sp->id_copy = NULL;
 				BLI_addtail(&pr_main->lamp, la);
 			}
 
@@ -473,16 +500,18 @@ static Scene *preview_prepare_scene(Main *bmain, Scene *scene, ID *id, int id_ty
 
 			if (la && la->nodetree && sp->pr_method == PR_NODE_RENDER) {
 				/* two previews, they get copied by wmJob */
-				BKE_node_preview_init_tree(origla->nodetree, sp->sizex, sp->sizey, true);
 				BKE_node_preview_init_tree(la->nodetree, sp->sizex, sp->sizey, true);
+				/* WATCH: Accessing origla is not safe! */
+				BKE_node_preview_init_tree(origla->nodetree, sp->sizex, sp->sizey, true);
 			}
 		}
 		else if (id_type == ID_WO) {
 			World *wrld = NULL, *origwrld = (World *)id;
 
 			if (origwrld) {
-				wrld = BKE_world_localize(origwrld);
-				sp->worldcopy = wrld;
+				BLI_assert(sp->id_copy != NULL);
+				wrld = sp->worldcopy = (World *)sp->id_copy;
+				sp->id_copy = NULL;
 				BLI_addtail(&pr_main->world, wrld);
 			}
 
@@ -492,6 +521,7 @@ static Scene *preview_prepare_scene(Main *bmain, Scene *scene, ID *id, int id_ty
 			if (wrld && wrld->nodetree && sp->pr_method == PR_NODE_RENDER) {
 				/* two previews, they get copied by wmJob */
 				BKE_node_preview_init_tree(wrld->nodetree, sp->sizex, sp->sizey, true);
+				/* WATCH: Accessing origwrld is not safe! */
 				BKE_node_preview_init_tree(origwrld->nodetree, sp->sizex, sp->sizey, true);
 			}
 		}
@@ -685,7 +715,11 @@ static void shader_preview_render(ShaderPreview *sp, ID *id, int split, int firs
 	char name[32];
 	int sizex;
 	Main *pr_main = sp->pr_main;
-	ID *id_eval = DEG_get_evaluated_id(sp->depsgraph, id);
+	ID *id_eval = id;
+
+	if (sp->depsgraph) {
+		id_eval = DEG_get_evaluated_id(sp->depsgraph, id);
+	}
 
 	/* in case of split preview, use border render */
 	if (split) {
@@ -794,6 +828,26 @@ static void shader_preview_free(void *customdata)
 	ShaderPreview *sp = customdata;
 	Main *pr_main = sp->pr_main;
 
+	if (sp->id_copy){
+		switch (GS(sp->id_copy->name)) {
+			case ID_MA:
+				BKE_material_free((Material *)sp->id_copy);
+				break;
+			case ID_TE:
+				BKE_texture_free((Tex *)sp->id_copy);
+				break;
+			case ID_LA:
+				BKE_lamp_free((Lamp *)sp->id_copy);
+				break;
+			case ID_WO:
+				BKE_world_free((World *)sp->id_copy);
+				break;
+			default:
+				BLI_assert(!"ID type preview not supported.");
+				break;
+		}
+		MEM_freeN(sp->id_copy);
+	}
 	if (sp->matcopy) {
 		struct IDProperty *properties;
 
@@ -1074,6 +1128,7 @@ static void icon_preview_startjob_all_sizes(void *customdata, short *stop, short
 		sp->pr_method = is_render ? PR_ICON_RENDER : PR_ICON_DEFERRED;
 		sp->pr_rect = cur_size->rect;
 		sp->id = ip->id;
+		sp->id_copy = ip->id_copy;
 		sp->bmain = ip->bmain;
 
 		if (is_render) {
@@ -1149,6 +1204,7 @@ void ED_preview_icon_render(Main *bmain, Scene *scene, ID *id, unsigned int *rec
 	ip.scene = scene;
 	ip.owner = BKE_previewimg_id_ensure(id);
 	ip.id = id;
+	ip.id_copy = duplicate_ids(id, NULL);
 
 	icon_preview_add_size(&ip, rect, sizex, sizey);
 
@@ -1183,6 +1239,7 @@ void ED_preview_icon_job(const bContext *C, void *owner, ID *id, unsigned int *r
 	ip->depsgraph = CTX_data_depsgraph(C);
 	ip->owner = owner;
 	ip->id = id;
+	ip->id_copy = duplicate_ids(id, ip->depsgraph);
 
 	icon_preview_add_size(ip, rect, sizex, sizey);
 
@@ -1231,6 +1288,7 @@ void ED_preview_shader_job(const bContext *C, void *owner, ID *id, ID *parent, M
 	sp->sizey = sizey;
 	sp->pr_method = method;
 	sp->id = id;
+	sp->id_copy = duplicate_ids(id, sp->depsgraph);
 	sp->parent = parent;
 	sp->slot = slot;
 	sp->bmain = CTX_data_main(C);