InputText: ImGuiInputTextCallbackData::InsertChars() accept (NULL,NUL…

…L) range, in order to conform to common idioms. (#6565, #6566, #3615)

docs/CHANGELOG.txt

@@ -88,6 +88,8 @@ Other changes:
 - CollapsingHeader/TreeNode: Fixed text padding when using _Framed+_Leaf flags. (#6549) [@BobbyAnguelov]
 - InputText: Fixed not returning true when buffer is cleared while using the
   ImGuiInputTextFlags_EscapeClearsAll flag. (#5688, #2620)
+- InputText: ImGuiInputTextCallbackData::InsertChars() accept (NULL,NULL) range, in order to conform
+  to common idioms (e.g. passing .data(), .data() + .size() from a null string). (#6565, #6566, #3615)
 - Combo: Made simple/legacy Combo() function not returns true when picking already selected item.
   This is consistent with other widgets. If you need something else, you can use BeginCombo(). (#1182)
 - Clipper: Rework inner logic to allow functioning with a zero-clear constructor.

imgui_widgets.cpp

@@ -3873,6 +3873,10 @@ void ImGuiInputTextCallbackData::DeleteChars(int pos, int bytes_count)
 
 void ImGuiInputTextCallbackData::InsertChars(int pos, const char* new_text, const char* new_text_end)
 {
+    // Accept null ranges
+    if (new_text == new_text_end)
+        return;
+
     const bool is_resizable = (Flags & ImGuiInputTextFlags_CallbackResize) != 0;
     const int new_text_len = new_text_end ? (int)(new_text_end - new_text) : (int)strlen(new_text);
     if (new_text_len + BufTextLen >= BufSize)