Cleanup: pass notifiers as const

24 files changed, 65 insertions, 60 deletions

diff --git a/source/blender/blenkernel/BKE_screen.h b/source/blender/blenkernel/BKE_screen.h
index a24a3e05dab..3691ab677b7 100644
--- a/source/blender/blenkernel/BKE_screen.h
+++ b/source/blender/blenkernel/BKE_screen.h
@@ -55,7 +55,7 @@ struct wmWindowManager;
 typedef struct wmSpaceTypeListenerParams {
   struct wmWindow *window;
   struct ScrArea *area;
-  struct wmNotifier *notifier;
+  const struct wmNotifier *notifier;
   const struct Scene *scene;
 } wmSpaceTypeListenerParams;
 
@@ -124,7 +124,7 @@ typedef struct wmRegionListenerParams {
   struct wmWindow *window;
   struct ScrArea *area; /* Can be NULL when the region is not part of an area. */
   struct ARegion *region;
-  struct wmNotifier *notifier;
+  const struct wmNotifier *notifier;
   const struct Scene *scene;
 } wmRegionListenerParams;
 
diff --git a/source/blender/editors/include/ED_screen.h b/source/blender/editors/include/ED_screen.h
index a24c8625a63..eeed1c9b286 100644
--- a/source/blender/editors/include/ED_screen.h
+++ b/source/blender/editors/include/ED_screen.h
@@ -294,7 +294,7 @@ void ED_screen_refresh(struct wmWindowManager *wm, struct wmWindow *win);
 void ED_screen_ensure_updated(struct wmWindowManager *wm,
                               struct wmWindow *win,
                               struct bScreen *screen);
-void ED_screen_do_listen(struct bContext *C, struct wmNotifier *note);
+void ED_screen_do_listen(struct bContext *C, const struct wmNotifier *note);
 /**
  * \brief Change the active screen.
  *
diff --git a/source/blender/editors/interface/interface_region_popup.cc b/source/blender/editors/interface/interface_region_popup.cc
index f6b078c033e..daa46b150a3 100644
--- a/source/blender/editors/interface/interface_region_popup.cc
+++ b/source/blender/editors/interface/interface_region_popup.cc
@@ -397,7 +397,7 @@ static void ui_block_region_draw(const bContext *C, ARegion *region)
 static void ui_block_region_popup_window_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   switch (wmn->category) {
     case NC_WINDOW: {
diff --git a/source/blender/editors/screen/area.c b/source/blender/editors/screen/area.c
index def6c38f5ca..9adb67dc372 100644
--- a/source/blender/editors/screen/area.c
+++ b/source/blender/editors/screen/area.c
@@ -127,7 +127,7 @@ void ED_region_pixelspace(const ARegion *region)
 void ED_region_do_listen(wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *notifier = params->notifier;
+  const wmNotifier *notifier = params->notifier;
 
   /* generic notes first */
   switch (notifier->category) {
diff --git a/source/blender/editors/screen/screen_edit.c b/source/blender/editors/screen/screen_edit.c
index 73195168d38..8d871ddee23 100644
--- a/source/blender/editors/screen/screen_edit.c
+++ b/source/blender/editors/screen/screen_edit.c
@@ -580,7 +580,7 @@ static void region_cursor_set(wmWindow *win, bool swin_changed)
   }
 }
 
-void ED_screen_do_listen(bContext *C, wmNotifier *note)
+void ED_screen_do_listen(bContext *C, const wmNotifier *note)
 {
   wmWindow *win = CTX_wm_window(C);
   bScreen *screen = CTX_wm_screen(C);
diff --git a/source/blender/editors/space_action/space_action.c b/source/blender/editors/space_action/space_action.c
index 166a4351377..fc0588dbab5 100644
--- a/source/blender/editors/space_action/space_action.c
+++ b/source/blender/editors/space_action/space_action.c
@@ -307,7 +307,7 @@ static void action_header_region_draw(const bContext *C, ARegion *region)
 static void action_channel_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
@@ -401,7 +401,7 @@ static void saction_channel_region_message_subscribe(const wmRegionMessageSubscr
 static void action_main_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
@@ -499,7 +499,7 @@ static void saction_main_region_message_subscribe(const wmRegionMessageSubscribe
 static void action_listener(const wmSpaceTypeListenerParams *params)
 {
   ScrArea *area = params->area;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
   SpaceAction *saction = (SpaceAction *)area->spacedata.first;
 
   /* context changes */
@@ -653,7 +653,7 @@ static void action_header_region_listener(const wmRegionListenerParams *params)
 {
   ScrArea *area = params->area;
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
   SpaceAction *saction = (SpaceAction *)area->spacedata.first;
 
   /* context changes */
@@ -728,7 +728,7 @@ static void action_buttons_area_draw(const bContext *C, ARegion *region)
 static void action_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
diff --git a/source/blender/editors/space_buttons/space_buttons.c b/source/blender/editors/space_buttons/space_buttons.c
index e60946b8f66..8026cc509b2 100644
--- a/source/blender/editors/space_buttons/space_buttons.c
+++ b/source/blender/editors/space_buttons/space_buttons.c
@@ -507,7 +507,7 @@ static void buttons_main_region_layout(const bContext *C, ARegion *region)
 static void buttons_main_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
@@ -645,7 +645,7 @@ static void buttons_area_redraw(ScrArea *area, short buttons)
 static void buttons_area_listener(const wmSpaceTypeListenerParams *params)
 {
   ScrArea *area = params->area;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
   SpaceProperties *sbuts = area->spacedata.first;
 
   /* context changes */
diff --git a/source/blender/editors/space_clip/space_clip.c b/source/blender/editors/space_clip/space_clip.c
index 4cf2e6e15e8..f8bf1893d89 100644
--- a/source/blender/editors/space_clip/space_clip.c
+++ b/source/blender/editors/space_clip/space_clip.c
@@ -314,7 +314,7 @@ static SpaceLink *clip_duplicate(SpaceLink *sl)
 static void clip_listener(const wmSpaceTypeListenerParams *params)
 {
   ScrArea *area = params->area;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
   const Scene *scene = params->scene;
 
   /* context changes */
@@ -919,7 +919,7 @@ static void clip_main_region_draw(const bContext *C, ARegion *region)
 static void clip_main_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
@@ -1118,7 +1118,7 @@ static void clip_header_region_draw(const bContext *C, ARegion *region)
 static void clip_header_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
@@ -1160,7 +1160,7 @@ static void clip_tools_region_draw(const bContext *C, ARegion *region)
 static void clip_props_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
@@ -1212,7 +1212,7 @@ static void clip_properties_region_draw(const bContext *C, ARegion *region)
 static void clip_properties_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
diff --git a/source/blender/editors/space_console/space_console.c b/source/blender/editors/space_console/space_console.c
index 90b3cec437c..7023c91ac85 100644
--- a/source/blender/editors/space_console/space_console.c
+++ b/source/blender/editors/space_console/space_console.c
@@ -257,7 +257,7 @@ static void console_main_region_listener(const wmRegionListenerParams *params)
 {
   ScrArea *area = params->area;
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
diff --git a/source/blender/editors/space_file/space_file.c b/source/blender/editors/space_file/space_file.c
index a462476aae0..b5cad0f6ff8 100644
--- a/source/blender/editors/space_file/space_file.c
+++ b/source/blender/editors/space_file/space_file.c
@@ -426,7 +426,7 @@ static void file_reset_filelist_showing_main_data(ScrArea *area, SpaceFile *sfil
 static void file_listener(const wmSpaceTypeListenerParams *listener_params)
 {
   ScrArea *area = listener_params->area;
-  wmNotifier *wmn = listener_params->notifier;
+  const wmNotifier *wmn = listener_params->notifier;
   SpaceFile *sfile = (SpaceFile *)area->spacedata.first;
 
   /* context changes */
@@ -514,7 +514,7 @@ static void file_main_region_init(wmWindowManager *wm, ARegion *region)
 static void file_main_region_listener(const wmRegionListenerParams *listener_params)
 {
   ARegion *region = listener_params->region;
-  wmNotifier *wmn = listener_params->notifier;
+  const wmNotifier *wmn = listener_params->notifier;
 
   /* context changes */
   switch (wmn->category) {
@@ -820,7 +820,7 @@ static void file_execution_region_draw(const bContext *C, ARegion *region)
 static void file_ui_region_listener(const wmRegionListenerParams *listener_params)
 {
   ARegion *region = listener_params->region;
-  wmNotifier *wmn = listener_params->notifier;
+  const wmNotifier *wmn = listener_params->notifier;
 
   /* context changes */
   switch (wmn->category) {
diff --git a/source/blender/editors/space_graph/space_graph.c b/source/blender/editors/space_graph/space_graph.c
index ea2e2e44b90..6a3db21cbaa 100644
--- a/source/blender/editors/space_graph/space_graph.c
+++ b/source/blender/editors/space_graph/space_graph.c
@@ -393,7 +393,7 @@ static void graph_buttons_region_draw(const bContext *C, ARegion *region)
 static void graph_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
@@ -529,7 +529,7 @@ static void graph_region_message_subscribe(const wmRegionMessageSubscribeParams
 static void graph_listener(const wmSpaceTypeListenerParams *params)
 {
   ScrArea *area = params->area;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
   SpaceGraph *sipo = (SpaceGraph *)area->spacedata.first;
 
   /* context changes */
diff --git a/source/blender/editors/space_image/space_image.c b/source/blender/editors/space_image/space_image.c
index 785a5419e04..00493d939ca 100644
--- a/source/blender/editors/space_image/space_image.c
+++ b/source/blender/editors/space_image/space_image.c
@@ -298,7 +298,7 @@ static void image_listener(const wmSpaceTypeListenerParams *params)
 {
   wmWindow *win = params->window;
   ScrArea *area = params->area;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
   SpaceImage *sima = (SpaceImage *)area->spacedata.first;
 
   /* context changes */
@@ -713,7 +713,7 @@ static void image_main_region_listener(const wmRegionListenerParams *params)
 {
   ScrArea *area = params->area;
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
@@ -827,7 +827,7 @@ static void image_buttons_region_draw(const bContext *C, ARegion *region)
 static void image_buttons_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
@@ -889,7 +889,7 @@ static void image_tools_region_draw(const bContext *C, ARegion *region)
 static void image_tools_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
@@ -945,7 +945,7 @@ static void image_header_region_draw(const bContext *C, ARegion *region)
 static void image_header_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
diff --git a/source/blender/editors/space_info/space_info.c b/source/blender/editors/space_info/space_info.c
index 73d81c93981..1513ba5e892 100644
--- a/source/blender/editors/space_info/space_info.c
+++ b/source/blender/editors/space_info/space_info.c
@@ -186,7 +186,7 @@ static void info_header_region_draw(const bContext *C, ARegion *region)
 static void info_main_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
@@ -202,7 +202,7 @@ static void info_main_region_listener(const wmRegionListenerParams *params)
 static void info_header_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
diff --git a/source/blender/editors/space_nla/space_nla.c b/source/blender/editors/space_nla/space_nla.c
index 1dd5bb41fef..ba7e8987dd5 100644
--- a/source/blender/editors/space_nla/space_nla.c
+++ b/source/blender/editors/space_nla/space_nla.c
@@ -303,7 +303,7 @@ static void nla_buttons_region_draw(const bContext *C, ARegion *region)
 static void nla_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
@@ -342,7 +342,7 @@ static void nla_region_listener(const wmRegionListenerParams *params)
 static void nla_main_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
@@ -436,7 +436,7 @@ static void nla_main_region_message_subscribe(const wmRegionMessageSubscribePara
 static void nla_channel_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
@@ -512,7 +512,7 @@ static void nla_channel_region_message_subscribe(const wmRegionMessageSubscribeP
 static void nla_listener(const wmSpaceTypeListenerParams *params)
 {
   ScrArea *area = params->area;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
diff --git a/source/blender/editors/space_node/space_node.cc b/source/blender/editors/space_node/space_node.cc
index 15afd024766..412611776a7 100644
--- a/source/blender/editors/space_node/space_node.cc
+++ b/source/blender/editors/space_node/space_node.cc
@@ -362,7 +362,7 @@ static void node_area_tag_tree_recalc(SpaceNode *snode, ScrArea *area)
 static void node_area_listener(const wmSpaceTypeListenerParams *params)
 {
   ScrArea *area = params->area;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* NOTE: #ED_area_tag_refresh will re-execute compositor. */
   SpaceNode *snode = (SpaceNode *)area->spacedata.first;
@@ -753,7 +753,7 @@ static void node_header_region_draw(const bContext *C, ARegion *region)
 static void node_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
   wmGizmoMap *gzmap = region->gizmo_map;
 
   /* context changes */
diff --git a/source/blender/editors/space_outliner/space_outliner.cc b/source/blender/editors/space_outliner/space_outliner.cc
index 04f326d62f9..76b7197b86a 100644
--- a/source/blender/editors/space_outliner/space_outliner.cc
+++ b/source/blender/editors/space_outliner/space_outliner.cc
@@ -95,7 +95,7 @@ static void outliner_main_region_listener(const wmRegionListenerParams *params)
 {
   ScrArea *area = params->area;
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
   SpaceOutliner *space_outliner = static_cast<SpaceOutliner *>(area->spacedata.first);
 
   /* context changes */
@@ -291,7 +291,7 @@ static void outliner_header_region_free(ARegion *UNUSED(region))
 static void outliner_header_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
diff --git a/source/blender/editors/space_sequencer/space_sequencer.c b/source/blender/editors/space_sequencer/space_sequencer.c
index 0199fa81928..201f132052d 100644
--- a/source/blender/editors/space_sequencer/space_sequencer.c
+++ b/source/blender/editors/space_sequencer/space_sequencer.c
@@ -374,7 +374,7 @@ static SpaceLink *sequencer_duplicate(SpaceLink *sl)
 static void sequencer_listener(const wmSpaceTypeListenerParams *params)
 {
   ScrArea *area = params->area;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* Context changes. */
   switch (wmn->category) {
@@ -630,7 +630,7 @@ static void sequencer_main_region_view2d_changed(const bContext *C, ARegion *reg
 static void sequencer_main_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* Context changes. */
   switch (wmn->category) {
@@ -862,7 +862,7 @@ static void sequencer_preview_region_draw(const bContext *C, ARegion *region)
 static void sequencer_preview_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   WM_gizmomap_tag_refresh(region->gizmo_map);
 
@@ -933,7 +933,7 @@ static void sequencer_buttons_region_draw(const bContext *C, ARegion *region)
 static void sequencer_buttons_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* Context changes. */
   switch (wmn->category) {
diff --git a/source/blender/editors/space_spreadsheet/space_spreadsheet.cc b/source/blender/editors/space_spreadsheet/space_spreadsheet.cc
index 8dbb4a2ee0c..5c0f69905fa 100644
--- a/source/blender/editors/space_spreadsheet/space_spreadsheet.cc
+++ b/source/blender/editors/space_spreadsheet/space_spreadsheet.cc
@@ -436,7 +436,7 @@ static void spreadsheet_main_region_draw(const bContext *C, ARegion *region)
 static void spreadsheet_main_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   switch (wmn->category) {
     case NC_SCENE: {
@@ -486,7 +486,7 @@ static void spreadsheet_header_region_free(ARegion *UNUSED(region))
 static void spreadsheet_header_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   switch (wmn->category) {
     case NC_SCENE: {
@@ -570,7 +570,7 @@ static void spreadsheet_footer_region_listener(const wmRegionListenerParams *UNU
 static void spreadsheet_dataset_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   switch (wmn->category) {
     case NC_SCENE: {
diff --git a/source/blender/editors/space_statusbar/space_statusbar.c b/source/blender/editors/space_statusbar/space_statusbar.c
index 273c0375fb0..9c64235870c 100644
--- a/source/blender/editors/space_statusbar/space_statusbar.c
+++ b/source/blender/editors/space_statusbar/space_statusbar.c
@@ -83,7 +83,7 @@ static void statusbar_keymap(struct wmKeyConfig *UNUSED(keyconf))
 static void statusbar_header_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
diff --git a/source/blender/editors/space_text/space_text.c b/source/blender/editors/space_text/space_text.c
index 1b4acda9bcf..62e2caa7596 100644
--- a/source/blender/editors/space_text/space_text.c
+++ b/source/blender/editors/space_text/space_text.c
@@ -109,7 +109,7 @@ static SpaceLink *text_duplicate(SpaceLink *sl)
 static void text_listener(const wmSpaceTypeListenerParams *params)
 {
   ScrArea *area = params->area;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
   SpaceText *st = area->spacedata.first;
 
   /* context changes */
diff --git a/source/blender/editors/space_topbar/space_topbar.c b/source/blender/editors/space_topbar/space_topbar.c
index bc68de1dfce..ee0e0c3ef46 100644
--- a/source/blender/editors/space_topbar/space_topbar.c
+++ b/source/blender/editors/space_topbar/space_topbar.c
@@ -116,7 +116,7 @@ static void topbar_header_region_init(wmWindowManager *UNUSED(wm), ARegion *regi
 static void topbar_main_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
@@ -146,7 +146,7 @@ static void topbar_main_region_listener(const wmRegionListenerParams *params)
 static void topbar_header_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
diff --git a/source/blender/editors/space_view3d/space_view3d.c b/source/blender/editors/space_view3d/space_view3d.c
index 1a2eb20d1a9..a9400bd7292 100644
--- a/source/blender/editors/space_view3d/space_view3d.c
+++ b/source/blender/editors/space_view3d/space_view3d.c
@@ -1037,7 +1037,7 @@ static void view3d_main_region_listener(const wmRegionListenerParams *params)
   wmWindow *window = params->window;
   ScrArea *area = params->area;
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
   const Scene *scene = params->scene;
   View3D *v3d = area->spacedata.first;
   RegionView3D *rv3d = region->regiondata;
@@ -1467,7 +1467,7 @@ static void view3d_header_region_draw(const bContext *C, ARegion *region)
 static void view3d_header_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
@@ -1684,7 +1684,7 @@ static void view3d_buttons_region_layout(const bContext *C, ARegion *region)
 static void view3d_buttons_region_listener(const wmRegionListenerParams *params)
 {
   ARegion *region = params->region;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
@@ -1807,7 +1807,7 @@ static void view3d_tools_region_draw(const bContext *C, ARegion *region)
 static void space_view3d_listener(const wmSpaceTypeListenerParams *params)
 {
   ScrArea *area = params->area;
-  wmNotifier *wmn = params->notifier;
+  const wmNotifier *wmn = params->notifier;
   View3D *v3d = area->spacedata.first;
 
   /* context changes */
diff --git a/source/blender/makesdna/DNA_windowmanager_types.h b/source/blender/makesdna/DNA_windowmanager_types.h
index 2586e13da39..47b7aee54d1 100644
--- a/source/blender/makesdna/DNA_windowmanager_types.h
+++ b/source/blender/makesdna/DNA_windowmanager_types.h
@@ -149,7 +149,12 @@ typedef struct wmWindowManager {
   /** Operator registry. */
   ListBase operators;
 
-  /** Refresh/redraw #wmNotifier structs. */
+  /**
+   * Refresh/redraw #wmNotifier structs.
+   * \note Once in the queue, notifiers should be considered read-only.
+   * With the exception of clearing notifiers for data which has been removed,
+   * see: #NOTE_CATEGORY_TAG_CLEARED.
+   */
   ListBase notifier_queue;
   /**
    * For duplicate detection.
diff --git a/source/blender/windowmanager/intern/wm_event_system.cc b/source/blender/windowmanager/intern/wm_event_system.cc
index 9cb5194a73b..d136d3831c9 100644
--- a/source/blender/windowmanager/intern/wm_event_system.cc
+++ b/source/blender/windowmanager/intern/wm_event_system.cc
@@ -492,7 +492,7 @@ void wm_event_do_notifiers(bContext *C)
 
     CTX_wm_window_set(C, win);
 
-    LISTBASE_FOREACH_MUTABLE (wmNotifier *, note, &wm->notifier_queue) {
+    LISTBASE_FOREACH_MUTABLE (const wmNotifier *, note, &wm->notifier_queue) {
       if (note->category == NC_WM) {
         if (ELEM(note->data, ND_FILEREAD, ND_FILESAVE)) {
           wm->file_saved = 1;
@@ -584,10 +584,10 @@ void wm_event_do_notifiers(bContext *C)
   }
 
   /* The notifiers are sent without context, to keep it clean. */
-  wmNotifier *note;
-  while ((note = static_cast<wmNotifier *>(BLI_pophead(&wm->notifier_queue)))) {
+  const wmNotifier *note;
+  while ((note = static_cast<const wmNotifier *>(BLI_pophead(&wm->notifier_queue)))) {
     if (wm_notifier_is_clear(note)) {
-      MEM_freeN(note);
+      MEM_freeN((void *)note);
       continue;
     }
     const bool removed = BLI_gset_remove(wm->notifier_queue_set, note, nullptr);
@@ -656,7 +656,7 @@ void wm_event_do_notifiers(bContext *C)
       }
     }
 
-    MEM_freeN(note);
+    MEM_freeN((void *)note);
   }
 #endif /* If 1 (postpone disabling for in favor of message-bus), eventually. */