Revert "Fix #130372: Implements memory of the previous state of eSpace_Types."

This reverts commit afec64739a.

The commit introduces a regression where opening the Asset Browser opens
the File Browser instead, same for other editor sub-types, see
blender/blender#134630.
blender/blender!134642 proposes a different solution and reverts this,
which I prefer too. Better to the revert separately from trying a
different fix for the initial bug, makes reviewing easier too.

source/blender/blenkernel/BKE_screen.hh

@@ -130,7 +130,6 @@ struct SpaceType {
   int (*space_subtype_get)(ScrArea *area);
   void (*space_subtype_set)(ScrArea *area, int value);
   void (*space_subtype_item_extend)(bContext *C, EnumPropertyItem **item, int *totitem);
-  int (*space_subtype_prev_get)(ScrArea *area);
 
   /* Return a custom name, based on subtype or other reason. */
   blender::StringRefNull (*space_name_get)(const ScrArea *area);

source/blender/editors/screen/area.cc

@@ -2601,9 +2601,7 @@ void ED_area_newspace(bContext *C, ScrArea *area, int type, const bool skip_regi
   wmWindow *win = CTX_wm_window(C);
   SpaceType *st = BKE_spacetype_from_id(type);
 
-  const bool change_spacetype = area->spacetype != type;
-
-  if (change_spacetype) {
+  if (area->spacetype != type) {
     SpaceLink *slold = static_cast<SpaceLink *>(area->spacedata.first);
     /* store area->type->exit callback */
     void (*area_exit)(wmWindowManager *, ScrArea *) = area->type ? area->type->exit : nullptr;
@@ -2712,13 +2710,10 @@ void ED_area_newspace(bContext *C, ScrArea *area, int type, const bool skip_regi
   }
 
   /* Set area space subtype if applicable. */
-  if (st && st->space_subtype_item_extend != nullptr) {
-    BLI_assert(st->space_subtype_prev_get != nullptr);
+  if (st->space_subtype_item_extend != nullptr) {
     st->space_subtype_set(area, area->butspacetype_subtype);
-    if (change_spacetype) {
-      st->space_subtype_set(area, st->space_subtype_prev_get(area));
-    }
   }
+  area->butspacetype_subtype = 0;
 
   if (BLI_listbase_is_single(&CTX_wm_screen(C)->areabase)) {
     /* If there is only one area update the window title. */

source/blender/editors/space_action/space_action.cc

@@ -874,8 +874,15 @@ static int action_space_subtype_get(ScrArea *area)
 static void action_space_subtype_set(ScrArea *area, int value)
 {
   SpaceAction *sact = static_cast<SpaceAction *>(area->spacedata.first);
-  sact->mode_prev = sact->mode;
-  sact->mode = value;
+  if (value == SACTCONT_TIMELINE) {
+    if (sact->mode != SACTCONT_TIMELINE) {
+      sact->mode_prev = sact->mode;
+    }
+    sact->mode = value;
+  }
+  else {
+    sact->mode = sact->mode_prev;
+  }
 }
 
 static void action_space_subtype_item_extend(bContext * /*C*/,
@@ -885,12 +892,6 @@ static void action_space_subtype_item_extend(bContext * /*C*/,
   RNA_enum_items_add(item, totitem, rna_enum_space_action_mode_items);
 }
 
-static int action_space_subtype_prev_get(ScrArea *area)
-{
-  SpaceAction *sact = static_cast<SpaceAction *>(area->spacedata.first);
-  return sact->mode_prev;
-}
-
 static blender::StringRefNull action_space_name_get(const ScrArea *area)
 {
   SpaceAction *sact = static_cast<SpaceAction *>(area->spacedata.first);
@@ -939,7 +940,6 @@ void ED_spacetype_action()
   st->space_subtype_item_extend = action_space_subtype_item_extend;
   st->space_subtype_get = action_space_subtype_get;
   st->space_subtype_set = action_space_subtype_set;
-  st->space_subtype_prev_get = action_space_subtype_prev_get;
   st->space_name_get = action_space_name_get;
   st->space_icon_get = action_space_icon_get;
   st->blend_read_data = action_space_blend_read_data;

source/blender/editors/space_file/space_file.cc

@@ -824,7 +824,6 @@ static void file_space_subtype_set(ScrArea *area, int value)
   LISTBASE_FOREACH (ARegion *, region, &area->regionbase) {
     region->v2d.flag &= ~V2D_IS_INIT;
   }
-  sfile->browse_mode_prev = sfile->browse_mode;
   sfile->browse_mode = value;
 }
 
@@ -833,12 +832,6 @@ static void file_space_subtype_item_extend(bContext * /*C*/, EnumPropertyItem **
   RNA_enum_items_add(item, totitem, rna_enum_space_file_browse_mode_items);
 }
 
-static int file_space_subtype_prev_get(ScrArea *area)
-{
-  SpaceFile *sfile = static_cast<SpaceFile *>(area->spacedata.first);
-  return sfile->browse_mode_prev;
-}
-
 static blender::StringRefNull file_space_name_get(const ScrArea *area)
 {
   SpaceFile *sfile = static_cast<SpaceFile *>(area->spacedata.first);
@@ -950,7 +943,6 @@ void ED_spacetype_file()
   st->space_subtype_item_extend = file_space_subtype_item_extend;
   st->space_subtype_get = file_space_subtype_get;
   st->space_subtype_set = file_space_subtype_set;
-  st->space_subtype_prev_get = file_space_subtype_prev_get;
   st->space_name_get = file_space_name_get;
   st->space_icon_get = file_space_icon_get;
   st->context = file_context;

source/blender/editors/space_graph/space_graph.cc

@@ -865,7 +865,6 @@ static int graph_space_subtype_get(ScrArea *area)
 static void graph_space_subtype_set(ScrArea *area, int value)
 {
   SpaceGraph *sgraph = static_cast<SpaceGraph *>(area->spacedata.first);
-  sgraph->mode_prev = sgraph->mode;
   sgraph->mode = value;
 }
 
@@ -876,12 +875,6 @@ static void graph_space_subtype_item_extend(bContext * /*C*/,
   RNA_enum_items_add(item, totitem, rna_enum_space_graph_mode_items);
 }
 
-static int graph_space_subtype_prev_get(ScrArea *area)
-{
-  SpaceGraph *sgraph = static_cast<SpaceGraph *>(area->spacedata.first);
-  return sgraph->mode_prev;
-}
-
 static blender::StringRefNull graph_space_name_get(const ScrArea *area)
 {
   SpaceGraph *sgraph = static_cast<SpaceGraph *>(area->spacedata.first);
@@ -944,7 +937,6 @@ void ED_spacetype_ipo()
   st->space_subtype_item_extend = graph_space_subtype_item_extend;
   st->space_subtype_get = graph_space_subtype_get;
   st->space_subtype_set = graph_space_subtype_set;
-  st->space_subtype_prev_get = graph_space_subtype_prev_get;
   st->space_name_get = graph_space_name_get;
   st->space_icon_get = graph_space_icon_get;
   st->blend_read_data = graph_space_blend_read_data;

source/blender/editors/space_image/space_image.cc

@@ -1062,8 +1062,15 @@ static int image_space_subtype_get(ScrArea *area)
 static void image_space_subtype_set(ScrArea *area, int value)
 {
   SpaceImage *sima = static_cast<SpaceImage *>(area->spacedata.first);
-  sima->mode_prev = sima->mode;
-  sima->mode = value;
+  if (value == SI_MODE_UV) {
+    if (sima->mode != SI_MODE_UV) {
+      sima->mode_prev = sima->mode;
+    }
+    sima->mode = value;
+  }
+  else {
+    sima->mode = sima->mode_prev;
+  }
 }
 
 static void image_space_subtype_item_extend(bContext * /*C*/,
@@ -1073,12 +1080,6 @@ static void image_space_subtype_item_extend(bContext * /*C*/,
   RNA_enum_items_add(item, totitem, rna_enum_space_image_mode_items);
 }
 
-static int image_space_subtype_prev_get(ScrArea *area)
-{
-  SpaceImage *sima = static_cast<SpaceImage *>(area->spacedata.first);
-  return sima->mode_prev;
-}
-
 static blender::StringRefNull image_space_name_get(const ScrArea *area)
 {
   SpaceImage *sima = static_cast<SpaceImage *>(area->spacedata.first);
@@ -1156,7 +1157,6 @@ void ED_spacetype_image()
   st->space_subtype_item_extend = image_space_subtype_item_extend;
   st->space_subtype_get = image_space_subtype_get;
   st->space_subtype_set = image_space_subtype_set;
-  st->space_subtype_prev_get = image_space_subtype_prev_get;
   st->space_name_get = image_space_name_get;
   st->space_icon_get = image_space_icon_get;
   st->blend_read_data = image_space_blend_read_data;

source/blender/editors/space_node/space_node.cc

@@ -1317,17 +1317,6 @@ static int node_space_subtype_get(ScrArea *area)
 static void node_space_subtype_set(ScrArea *area, int value)
 {
   SpaceNode *snode = static_cast<SpaceNode *>(area->spacedata.first);
-  int value_prev = node_space_subtype_get(area);
-
-  /* Save the subtype. */
-  blender::bke::bNodeTreeType *typeinfo = rna_node_tree_type_from_enum(value_prev);
-  if (typeinfo) {
-    STRNCPY(snode->tree_idname_prev, typeinfo->idname.c_str());
-  }
-  else {
-    snode->tree_idname_prev[0] = '\0';
-  }
-
   ED_node_set_tree_type(snode, rna_node_tree_type_from_enum(value));
 }
 
@@ -1341,12 +1330,6 @@ static void node_space_subtype_item_extend(bContext *C, EnumPropertyItem **item,
   }
 }
 
-static int node_space_subtype_prev_get(ScrArea *area)
-{
-  SpaceNode *snode = static_cast<SpaceNode *>(area->spacedata.first);
-  return rna_node_tree_idname_to_enum(snode->tree_idname_prev);
-}
-
 static blender::StringRefNull node_space_name_get(const ScrArea *area)
 {
   SpaceNode *snode = static_cast<SpaceNode *>(area->spacedata.first);
@@ -1420,7 +1403,6 @@ void ED_spacetype_node()
   st->space_subtype_item_extend = node_space_subtype_item_extend;
   st->space_subtype_get = node_space_subtype_get;
   st->space_subtype_set = node_space_subtype_set;
-  st->space_subtype_prev_get = node_space_subtype_prev_get;
   st->space_name_get = node_space_name_get;
   st->space_icon_get = node_space_icon_get;
   st->blend_read_data = node_space_blend_read_data;

source/blender/makesdna/DNA_screen_types.h

@@ -439,7 +439,6 @@ typedef struct ScrArea {
    */
   char butspacetype;
   short butspacetype_subtype;
-  short butspacetype_subtype_prev;
 
   /** Size. */
   short winx, winy;
@@ -454,6 +453,7 @@ typedef struct ScrArea {
    * runtime variable, updated by executing operators.
    */
   short region_active_win;
+  char _pad[2];
 
   /** Callbacks for this space type. */
   struct SpaceType *type;

source/blender/makesdna/DNA_space_types.h

@@ -484,10 +484,8 @@ typedef struct SpaceGraph {
 
   /** Mode for the Graph editor (eGraphEdit_Mode). */
   short mode;
-  short mode_prev;
   /* Snapping now lives on the Scene. */
   short autosnap DNA_DEPRECATED;
-  char _pad[2];
   /** Settings for Graph editor (eGraphEdit_Flag). */
   int flag;
 
@@ -497,6 +495,7 @@ typedef struct SpaceGraph {
   float cursorVal;
   /** Pivot point for transforms. */
   int around;
+  char _pad[4];
 
   SpaceGraph_Runtime runtime;
 } SpaceGraph;
@@ -915,7 +914,7 @@ typedef struct SpaceFile {
 
   /** Is this a File Browser or an Asset Browser? */
   char browse_mode; /* eFileBrowse_Mode */
-  char browse_mode_prev;
+  char _pad1[1];
 
   short tags;
 
@@ -1610,7 +1609,6 @@ typedef struct SpaceNode {
 
   /* tree type for the current node tree */
   char tree_idname[64];
-  char tree_idname_prev[64];
   /** Same as #bNodeTree::type (deprecated). */
   int treetype DNA_DEPRECATED;