PyAPI: support Operator.poll functions 'disabled' hint

Python scripts can now define the reason it's poll function fails using:

`Operator.poll_message_set(message, ...)`

This supports both regular text as well as delaying message creation
using a callback which should be used in situations where constructing
detailed messages is too much overhead for a poll function.

Ref D11001

1 files changed, 5 insertions, 1 deletions

diff --git a/source/blender/editors/interface/interface_region_tooltip.c b/source/blender/editors/interface/interface_region_tooltip.c
index e5287ee6733..accfb78ab94 100644
--- a/source/blender/editors/interface/interface_region_tooltip.c
+++ b/source/blender/editors/interface/interface_region_tooltip.c
@@ -947,12 +947,13 @@ static uiTooltipData *ui_tooltip_data_from_button(bContext *C, uiBut *but)
   /* button is disabled, we may be able to tell user why */
   if (but->flag & UI_BUT_DISABLED) {
     const char *disabled_msg = NULL;
+    bool disabled_msg_free = false;
 
     /* if operator poll check failed, it can give pretty precise info why */
     if (but->optype) {
       CTX_wm_operator_poll_msg_clear(C);
       WM_operator_poll_context(C, but->optype, but->opcontext);
-      disabled_msg = CTX_wm_operator_poll_msg_get(C);
+      disabled_msg = CTX_wm_operator_poll_msg_get(C, &disabled_msg_free);
     }
     /* alternatively, buttons can store some reasoning too */
     else if (but->disabled_info) {
@@ -967,6 +968,9 @@ static uiTooltipData *ui_tooltip_data_from_button(bContext *C, uiBut *but)
                                              });
       field->text = BLI_sprintfN(TIP_("Disabled: %s"), disabled_msg);
     }
+    if (disabled_msg_free) {
+      MEM_freeN((void *)disabled_msg);
+    }
   }
 
   if ((U.flag & USER_TOOLTIPS_PYTHON) && !but->optype && rna_struct.strinfo) {