Fixes for PVS Studio and MSVC static analyzers. Using a macro to suppress single-use MSVC false positives. (#3938, #4073)

imgui.cpp

@@ -816,8 +816,9 @@ CODE
 #if defined(_MSC_VER) && _MSC_VER >= 1922   // MSVC 2019 16.2 or later
 #pragma warning (disable: 5054)             // operator '|': deprecated between enumerations of different types
 #endif
-#pragma warning (disable: 26451)            // Arithmetic overflow : Using operator 'xxx' on a 4 byte value and then casting the result to a 8 byte value. Cast the value to the wider type before calling operator 'xxx' to avoid overflow(io.2).
-#pragma warning (disable: 26812)            // The enum type 'xxx' is unscoped. Prefer 'enum class' over 'enum' (Enum.3). [MSVC Static Analyzer)
+#pragma warning (disable: 26451)            // [Static Analyzer] Arithmetic overflow : Using operator 'xxx' on a 4 byte value and then casting the result to a 8 byte value. Cast the value to the wider type before calling operator 'xxx' to avoid overflow(io.2).
+#pragma warning (disable: 26495)            // [Static Analyzer] Variable 'XXX' is uninitialized. Always initialize a member variable (type.6).
+#pragma warning (disable: 26812)            // [Static Analyzer] The enum type 'xxx' is unscoped. Prefer 'enum class' over 'enum' (Enum.3).
 #endif
 
 // Clang/GCC warnings with -Weverything
@@ -4475,6 +4476,7 @@ void ImGui::Render()
     for (int n = 0; n != g.Windows.Size; n++)
     {
         ImGuiWindow* window = g.Windows[n];
+        IM_MSVC_WARNING_SUPPRESS(6011); // Static Analysis false positive "warning C6011: Dereferencing NULL pointer 'window'"
         if (IsWindowActiveAndVisible(window) && (window->Flags & ImGuiWindowFlags_ChildWindow) == 0 && window != windows_to_render_top_most[0] && window != windows_to_render_top_most[1])
             AddRootWindowToDrawData(window);
     }
@@ -4576,9 +4578,9 @@ static void FindHoveredWindow()
                 continue;
         }
 
-        IM_ASSERT(window != NULL); // fix C28182
         if (hovered_window == NULL)
             hovered_window = window;
+        IM_MSVC_WARNING_SUPPRESS(28182); // [Static Analyzer] Dereferencing NULL pointer.
         if (hovered_window_ignoring_moving_window == NULL && (!g.MovingWindow || window->RootWindow != g.MovingWindow->RootWindow))
             hovered_window_ignoring_moving_window = window;
         if (hovered_window && hovered_window_ignoring_moving_window)
@@ -9714,6 +9716,7 @@ void ImGui::NavUpdateWindowingOverlay()
     for (int n = g.WindowsFocusOrder.Size - 1; n >= 0; n--)
     {
         ImGuiWindow* window = g.WindowsFocusOrder[n];
+        IM_MSVC_WARNING_SUPPRESS(6011); // Static Analysis false positive "warning C6011: Dereferencing NULL pointer 'window'"
         if (!IsWindowNavFocusable(window))
             continue;
         const char* label = window->Name;

imgui.h

@@ -103,7 +103,7 @@ Index of this file:
 // Warnings
 #ifdef _MSC_VER
 #pragma warning (push)
-#pragma warning (disable: 26495) // Variable 'XXX' is uninitialized. Always initialize a member variable (type.6). // (VS2019 Static Analyzer arguably is buggy as of 16.9.4, will reconsider)
+#pragma warning (disable: 26495)    // [Static Analyzer] Variable 'XXX' is uninitialized. Always initialize a member variable (type.6).
 #endif
 #if defined(__clang__)
 #pragma clang diagnostic push

imgui_demo.cpp

@@ -93,7 +93,7 @@ Index of this file:
 // Visual Studio warnings
 #ifdef _MSC_VER
 #pragma warning (disable: 4996)     // 'This function or variable may be unsafe': strcpy, strdup, sprintf, vsnprintf, sscanf, fopen
-#pragma warning (disable: 26451)    // Arithmetic overflow : Using operator 'xxx' on a 4 byte value and then casting the result to a 8 byte value. Cast the value to the wider type before calling operator 'xxx' to avoid overflow(io.2).
+#pragma warning (disable: 26451)    // [Static Analyzer] Arithmetic overflow : Using operator 'xxx' on a 4 byte value and then casting the result to a 8 byte value. Cast the value to the wider type before calling operator 'xxx' to avoid overflow(io.2).
 #endif
 
 // Clang/GCC warnings with -Weverything

imgui_draw.cpp

@@ -57,9 +57,9 @@ Index of this file:
 #pragma warning (disable: 4127)     // condition expression is constant
 #pragma warning (disable: 4505)     // unreferenced local function has been removed (stb stuff)
 #pragma warning (disable: 4996)     // 'This function or variable may be unsafe': strcpy, strdup, sprintf, vsnprintf, sscanf, fopen
-#pragma warning (disable: 6255)     // _alloca indicates failure by raising a stack overflow exception.  Consider using _malloca instead.
-#pragma warning (disable: 26451)    // Arithmetic overflow : Using operator 'xxx' on a 4 byte value and then casting the result to a 8 byte value. Cast the value to the wider type before calling operator 'xxx' to avoid overflow(io.2).
-#pragma warning (disable: 26812)    // The enum type 'xxx' is unscoped. Prefer 'enum class' over 'enum' (Enum.3). [MSVC Static Analyzer)
+#pragma warning (disable: 6255)     // [Static Analyzer] _alloca indicates failure by raising a stack overflow exception.  Consider using _malloca instead.
+#pragma warning (disable: 26451)    // [Static Analyzer] Arithmetic overflow : Using operator 'xxx' on a 4 byte value and then casting the result to a 8 byte value. Cast the value to the wider type before calling operator 'xxx' to avoid overflow(io.2).
+#pragma warning (disable: 26812)    // [Static Analyzer] The enum type 'xxx' is unscoped. Prefer 'enum class' over 'enum' (Enum.3). [MSVC Static Analyzer)
 #endif
 
 // Clang/GCC warnings with -Weverything
@@ -108,6 +108,9 @@ namespace IMGUI_STB_NAMESPACE
 #ifdef _MSC_VER
 #pragma warning (push)
 #pragma warning (disable: 4456)                             // declaration of 'xx' hides previous local declaration
+#pragma warning (disable: 6011)                             // (stb_rectpack) Dereferencing NULL pointer 'cur->next'.
+#pragma warning (disable: 6385)                             // (stb_truetype) Reading invalid data from 'buffer':  the readable size is '_Old_3`kernel_width' bytes, but '3' bytes may be read.
+#pragma warning (disable: 28182)                            // (stb_rectpack) Dereferencing NULL pointer. 'cur' contains the same NULL value as 'cur->next' did.
 #endif
 
 #if defined(__clang__)

imgui_internal.h

@@ -54,8 +54,10 @@ Index of this file:
 // Visual Studio warnings
 #ifdef _MSC_VER
 #pragma warning (push)
-#pragma warning (disable: 4251) // class 'xxx' needs to have dll-interface to be used by clients of struct 'xxx' // when IMGUI_API is set to__declspec(dllexport)
-#pragma warning (disable: 26812)// The enum type 'xxx' is unscoped. Prefer 'enum class' over 'enum' (Enum.3). [MSVC Static Analyzer)
+#pragma warning (disable: 4251)     // class 'xxx' needs to have dll-interface to be used by clients of struct 'xxx' // when IMGUI_API is set to__declspec(dllexport)
+#pragma warning (disable: 26812)    // The enum type 'xxx' is unscoped. Prefer 'enum class' over 'enum' (Enum.3). [MSVC Static Analyzer)
+#pragma warning (disable: 26495)    // [Static Analyzer] Variable 'XXX' is uninitialized. Always initialize a member variable (type.6).
+
 #endif
 
 // Clang/GCC warnings with -Weverything
@@ -229,6 +231,13 @@ namespace ImStb
 #define IMGUI_CDECL
 #endif
 
+// Warnings
+#if defined(_MSC_VER) && !defined(__clang__)
+#define IM_MSVC_WARNING_SUPPRESS(XXXX)  __pragma(warning(suppress: XXXX))
+#else
+#define IM_MSVC_WARNING_SUPPRESS(XXXX)
+#endif
+
 // Debug Tools
 // Use 'Metrics->Tools->Item Picker' to break into the call-stack of a specific item.
 #ifndef IM_DEBUG_BREAK

imgui_tables.cpp

@@ -210,8 +210,8 @@ Index of this file:
 #if defined(_MSC_VER) && _MSC_VER >= 1922 // MSVC 2019 16.2 or later
 #pragma warning (disable: 5054)     // operator '|': deprecated between enumerations of different types
 #endif
-#pragma warning (disable: 26451)    // Arithmetic overflow : Using operator 'xxx' on a 4 byte value and then casting the result to a 8 byte value. Cast the value to the wider type before calling operator 'xxx' to avoid overflow(io.2).
-#pragma warning (disable: 26812)    // The enum type 'xxx' is unscoped. Prefer 'enum class' over 'enum' (Enum.3). [MSVC Static Analyzer)
+#pragma warning (disable: 26451)    // [Static Analyzer] Arithmetic overflow : Using operator 'xxx' on a 4 byte value and then casting the result to a 8 byte value. Cast the value to the wider type before calling operator 'xxx' to avoid overflow(io.2).
+#pragma warning (disable: 26812)    // [Static Analyzer] The enum type 'xxx' is unscoped. Prefer 'enum class' over 'enum' (Enum.3).
 #endif
 
 // Clang/GCC warnings with -Weverything

imgui_widgets.cpp

@@ -59,8 +59,8 @@ Index of this file:
 #if defined(_MSC_VER) && _MSC_VER >= 1922 // MSVC 2019 16.2 or later
 #pragma warning (disable: 5054)     // operator '|': deprecated between enumerations of different types
 #endif
-#pragma warning (disable: 26451)    // Arithmetic overflow : Using operator 'xxx' on a 4 byte value and then casting the result to a 8 byte value. Cast the value to the wider type before calling operator 'xxx' to avoid overflow(io.2).
-#pragma warning (disable: 26812)    // The enum type 'xxx' is unscoped. Prefer 'enum class' over 'enum' (Enum.3). [MSVC Static Analyzer)
+#pragma warning (disable: 26451)    // [Static Analyzer] Arithmetic overflow : Using operator 'xxx' on a 4 byte value and then casting the result to a 8 byte value. Cast the value to the wider type before calling operator 'xxx' to avoid overflow(io.2).
+#pragma warning (disable: 26812)    // [Static Analyzer] The enum type 'xxx' is unscoped. Prefer 'enum class' over 'enum' (Enum.3).
 #endif
 
 // Clang/GCC warnings with -Weverything
@@ -4818,10 +4818,12 @@ bool ImGui::ColorEdit4(const char* label, float col[4], ImGuiColorEditFlags flag
                 p++;
             i[0] = i[1] = i[2] = 0;
             i[3] = 0xFF; // alpha default to 255 is not parsed by scanf (e.g. inputting #FFFFFF omitting alpha)
+            int r;
             if (alpha)
-                sscanf(p, "%02X%02X%02X%02X", (unsigned int*)&i[0], (unsigned int*)&i[1], (unsigned int*)&i[2], (unsigned int*)&i[3]); // Treat at unsigned (%X is unsigned)
+                r = sscanf(p, "%02X%02X%02X%02X", (unsigned int*)&i[0], (unsigned int*)&i[1], (unsigned int*)&i[2], (unsigned int*)&i[3]); // Treat at unsigned (%X is unsigned)
             else
-                sscanf(p, "%02X%02X%02X", (unsigned int*)&i[0], (unsigned int*)&i[1], (unsigned int*)&i[2]);
+                r = sscanf(p, "%02X%02X%02X", (unsigned int*)&i[0], (unsigned int*)&i[1], (unsigned int*)&i[2]);
+            IM_UNUSED(r); // Fixes C6031: Return value ignored: 'sscanf'.
         }
         if (!(flags & ImGuiColorEditFlags_NoOptions))
             OpenPopupOnItemClick("context");
@@ -6603,6 +6605,7 @@ void ImGui::EndMenuBar()
         }
     }
 
+    IM_MSVC_WARNING_SUPPRESS(6011); // Static Analysis false positive "warning C6011: Dereferencing NULL pointer 'window'"
     IM_ASSERT(window->Flags & ImGuiWindowFlags_MenuBar);
     IM_ASSERT(window->DC.MenuBarAppending);
     PopClipRect();
@@ -7234,6 +7237,7 @@ static void ImGui::TabBarLayout(ImGuiTabBar* tab_bar)
         curr_section_n = section_n;
 
         // Store data so we can build an array sorted by width if we need to shrink tabs down
+        IM_MSVC_WARNING_SUPPRESS(6385);
         int shrink_buffer_index = shrink_buffer_indexes[section_n]++;
         g.ShrinkWidthBuffer[shrink_buffer_index].Index = tab_n;
         g.ShrinkWidthBuffer[shrink_buffer_index].Width = tab->ContentWidth;