TextUnformatted: Accept null ranges including (NULL,NULL) without asserting. (#3615)

docs/CHANGELOG.txt

@@ -44,6 +44,8 @@ Other Changes:
 
 - InputTextMultiline: Fixed label size not being included into window contents rect unless
   the whole widget is clipped.
+- TextUnformatted: Accept null ranges including (NULL,NULL) without asserting, in order to conform
+  to common idioms (e.g. passing .data(), .data() + .size() from a null string). (#3615)
 - Fonts: imgui_freetype: Fixed crash when FT_Render_Glyph() fails to render a glyph and returns NULL
   (which apparently happens with Freetype 2.11). (#4394, #4145?).
 - Fonts: Fixed ImFontAtlas::ClearInputData() marking atlas as not built. (#4455, #3487)

imgui.h

@@ -61,7 +61,7 @@ Index of this file:
 // Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals. Work in progress versions typically starts at XYY99 then bounce up to XYY00, XYY01 etc. when release tagging happens)
 #define IMGUI_VERSION               "1.85 WIP"
-#define IMGUI_VERSION_NUM           18407
+#define IMGUI_VERSION_NUM           18408
 #define IMGUI_CHECKVERSION()        ImGui::DebugCheckVersionAndDataLayout(IMGUI_VERSION, sizeof(ImGuiIO), sizeof(ImGuiStyle), sizeof(ImVec2), sizeof(ImVec4), sizeof(ImDrawVert), sizeof(ImDrawIdx))
 #define IMGUI_HAS_TABLE
 

imgui_widgets.cpp

@@ -152,9 +152,13 @@ void ImGui::TextEx(const char* text, const char* text_end, ImGuiTextFlags flags)
     ImGuiWindow* window = GetCurrentWindow();
     if (window->SkipItems)
         return;
-
     ImGuiContext& g = *GImGui;
-    IM_ASSERT(text != NULL);
+
+    // Accept null ranges
+    if (text == text_end)
+        text = text_end = "";
+
+    // Calculate length
     const char* text_begin = text;
     if (text_end == NULL)
         text_end = text + strlen(text); // FIXME-OPT