Tabs: Enforcing minimum size of 1.0f, fixed asserting on zero-tab widths. (#5572)

Also fixed SetNextItemWidth(0.0f) not being consistent with tabs. (#5262)

docs/CHANGELOG.txt

@@ -100,6 +100,7 @@ Other Changes:
 - Tabs: Fixed shrinking policy leading to infinite loops when fed unrounded tab widths. (#5652)
 - Tabs: Fixed shrinking policy sometimes erroneously making right-most tabs stray a little out
   bar boundaries (bug in 1.88). (#5652).
+- Tabs: Enforcing minimum size of 1.0f, fixed asserting on zero-tab widths. (#5572)
 - Window: Fixed a potential crash when appending to a child window. (#5515, #3496, #4797) [@rokups]
 - IO: Added ImGuiKey_MouseXXX aliases for mouse buttons/wheel so all operations done on ImGuiKey
   can apply to mouse data as well. (#4921)

imgui_widgets.cpp

@@ -7552,7 +7552,7 @@ static void ImGui::TabBarLayout(ImGuiTabBar* tab_bar)
         // and we cannot wait for the next BeginTabItem() call. We cannot compute this width within TabBarAddTab() because font size depends on the active window.
         const char* tab_name = tab_bar->GetTabName(tab);
         const bool has_close_button = (tab->Flags & ImGuiTabItemFlags_NoCloseButton) ? false : true;
-        tab->ContentWidth = (tab->RequestedWidth > 0.0f) ? tab->RequestedWidth : TabItemCalcSize(tab_name, has_close_button).x;
+        tab->ContentWidth = (tab->RequestedWidth >= 0.0f) ? tab->RequestedWidth : TabItemCalcSize(tab_name, has_close_button).x;
 
         int section_n = TabItemGetSectionIdx(tab);
         ImGuiTabBarSection* section = &sections[section_n];
@@ -7564,9 +7564,7 @@ static void ImGui::TabBarLayout(ImGuiTabBar* tab_bar)
         ImGuiShrinkWidthItem* shrink_width_item = &g.ShrinkWidthBuffer[shrink_buffer_indexes[section_n]++];
         shrink_width_item->Index = tab_n;
         shrink_width_item->Width = shrink_width_item->InitialWidth = tab->ContentWidth;
-
-        IM_ASSERT(tab->ContentWidth > 0.0f);
-        tab->Width = tab->ContentWidth;
+        tab->Width = ImMax(tab->ContentWidth, 1.0f);
     }
 
     // Compute total ideal width (used for e.g. auto-resizing a window)
@@ -7610,6 +7608,7 @@ static void ImGui::TabBarLayout(ImGuiTabBar* tab_bar)
             if (shrinked_width < 0.0f)
                 continue;
 
+            shrinked_width = ImMax(1.0f, shrinked_width);
             int section_n = TabItemGetSectionIdx(tab);
             sections[section_n].Width -= (tab->Width - shrinked_width);
             tab->Width = shrinked_width;
@@ -8085,7 +8084,7 @@ bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open,
     if (g.NextItemData.Flags & ImGuiNextItemDataFlags_HasWidth)
         size.x = tab->RequestedWidth = g.NextItemData.Width;
     if (tab_is_new)
-        tab->Width = size.x;
+        tab->Width = ImMax(1.0f, size.x);
     tab->ContentWidth = size.x;
     tab->BeginOrder = tab_bar->TabsActiveCount++;