Fixes for Visual Studio 2019 static analyzers. (#3938, #4073) + two minor edge case were invalid scalar input (e.g. a sign only) would return buffer as modified.

backends/imgui_impl_dx10.cpp

@@ -293,6 +293,7 @@ static void ImGui_ImplDX10_CreateFontsTexture()
         subResource.SysMemPitch = desc.Width * 4;
         subResource.SysMemSlicePitch = 0;
         g_pd3dDevice->CreateTexture2D(&desc, &subResource, &pTexture);
+        IM_ASSERT(pTexture != NULL);
 
         // Create texture view
         D3D10_SHADER_RESOURCE_VIEW_DESC srv_desc;

backends/imgui_impl_dx11.cpp

@@ -305,6 +305,7 @@ static void ImGui_ImplDX11_CreateFontsTexture()
         subResource.SysMemPitch = desc.Width * 4;
         subResource.SysMemSlicePitch = 0;
         g_pd3dDevice->CreateTexture2D(&desc, &subResource, &pTexture);
+        IM_ASSERT(pTexture != NULL);
 
         // Create texture view
         D3D11_SHADER_RESOURCE_VIEW_DESC srvDesc;

docs/TODO.txt

@@ -352,7 +352,7 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - nav/windowing: Resizing window will currently fail with certain types of resizing constraints/callback applied
  - focus: preserve ActiveId/focus stack state, e.g. when opening a menu and close it, previously selected InputText() focus gets restored (#622)
  - focus: SetKeyboardFocusHere() on with >= 0 offset could be done on same frame (else latch and modulate on beginning of next frame)
- - focus: unable to use SetKeyboardFocusHere() on clipped widgets. (#787)
+ - focus: unable to use SetKeyboardFocusHere() on clipped widgets. (#787, #343)
 
  - inputs: we need an explicit flag about whether the imgui window is focused, to be able to distinguish focused key releases vs alt-tabbing all release behaviors.
  - inputs: rework IO system to be able to pass actual ordered/timestamped events. use an event queue? (~#335, #71)

imgui.cpp

@@ -816,6 +816,8 @@ 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)
 #endif
 
 // Clang/GCC warnings with -Weverything
@@ -4574,6 +4576,7 @@ static void FindHoveredWindow()
                 continue;
         }
 
+        IM_ASSERT(window != NULL); // fix C28182
         if (hovered_window == NULL)
             hovered_window = window;
         if (hovered_window_ignoring_moving_window == NULL && (!g.MovingWindow || window->RootWindow != g.MovingWindow->RootWindow))

imgui.h

@@ -101,6 +101,10 @@ Index of this file:
 #endif
 
 // 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)
+#endif
 #if defined(__clang__)
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wold-style-cast"
@@ -2823,6 +2827,10 @@ enum ImDrawCornerFlags_
 #pragma GCC diagnostic pop
 #endif
 
+#ifdef _MSC_VER
+#pragma warning (pop)
+#endif
+
 // Include imgui_user.h at the end of imgui.h (convenient for user to only explicitly include vanilla imgui.h)
 #ifdef IMGUI_INCLUDE_IMGUI_USER_H
 #include "imgui_user.h"

imgui_demo.cpp

@@ -92,7 +92,8 @@ 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: 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).
 #endif
 
 // Clang/GCC warnings with -Weverything

imgui_draw.cpp

@@ -54,9 +54,12 @@ Index of this file:
 
 // Visual Studio warnings
 #ifdef _MSC_VER
-#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: 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)
 #endif
 
 // Clang/GCC warnings with -Weverything

imgui_internal.h

@@ -55,6 +55,7 @@ Index of this file:
 #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)
 #endif
 
 // Clang/GCC warnings with -Weverything
@@ -492,12 +493,12 @@ inline void     ImBitArraySetBitRange(ImU32* arr, int n, int n2) // Works on ran
 }
 
 // Helper: ImBitArray class (wrapper over ImBitArray functions)
-// Store 1-bit per value. NOT CLEARED by constructor.
+// Store 1-bit per value.
 template<int BITCOUNT>
 struct IMGUI_API ImBitArray
 {
     ImU32           Storage[(BITCOUNT + 31) >> 5];
-    ImBitArray()                                { }
+    ImBitArray()                                { ClearAllBits(); }
     void            ClearAllBits()              { memset(Storage, 0, sizeof(Storage)); }
     void            SetAllBits()                { memset(Storage, 255, sizeof(Storage)); }
     bool            TestBit(int n) const        { IM_ASSERT(n < BITCOUNT); return ImBitArrayTestBit(Storage, n); }
@@ -1440,7 +1441,7 @@ struct ImGuiContext
     int                     TabFocusRequestCurrCounterTabStop;  // Tab item being requested for focus, stored as an index
     int                     TabFocusRequestNextCounterRegular;  // Stored for next frame
     int                     TabFocusRequestNextCounterTabStop;  // "
-    bool                    TabFocusPressed;                    //
+    bool                    TabFocusPressed;                    // Set in NewFrame() when user pressed Tab
 
     // Render
     float                   DimBgRatio;                         // 0.0..1.0 animation when fading in a dimming background (for modal window and CTRL+TAB list)

imgui_tables.cpp

@@ -210,6 +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)
 #endif
 
 // Clang/GCC warnings with -Weverything
@@ -2301,10 +2303,11 @@ void ImGui::TableMergeDrawChannels(ImGuiTable* table)
         ImRect  ClipRect;
         int     ChannelsCount;
         ImBitArray<IMGUI_TABLE_MAX_DRAW_CHANNELS> ChannelsMask;
+
+        MergeGroup() { ChannelsCount = 0; }
     };
     int merge_group_mask = 0x00;
     MergeGroup merge_groups[4];
-    memset(merge_groups, 0, sizeof(merge_groups));
 
     // 1. Scan channels and take note of those which can be merged
     for (int column_n = 0; column_n < table->ColumnsCount; column_n++)
@@ -2382,7 +2385,6 @@ void ImGui::TableMergeDrawChannels(ImGuiTable* table)
         g.DrawChannelsTempMergeBuffer.resize(splitter->_Count - LEADING_DRAW_CHANNELS); // Use shared temporary storage so the allocation gets amortized
         ImDrawChannel* dst_tmp = g.DrawChannelsTempMergeBuffer.Data;
         ImBitArray<IMGUI_TABLE_MAX_DRAW_CHANNELS> remaining_mask;                       // We need 132-bit of storage
-        remaining_mask.ClearAllBits();
         remaining_mask.SetBitRange(LEADING_DRAW_CHANNELS, splitter->_Count);
         remaining_mask.ClearBit(table->Bg2DrawChannelUnfrozen);
         IM_ASSERT(has_freeze_v == false || table->Bg2DrawChannelUnfrozen != TABLE_DRAW_CHANNEL_BG2_FROZEN);

imgui_widgets.cpp

@@ -59,6 +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)
 #endif
 
 // Clang/GCC warnings with -Weverything
@@ -1980,13 +1982,15 @@ bool ImGui::DataTypeApplyOpFromText(const char* buf, const char* initial_value_b
     {
         // All other types assign constant
         // We don't bother handling support for legacy operators since they are a little too crappy. Instead we will later implement a proper expression evaluator in the future.
-        sscanf(buf, format, p_data);
+        if (sscanf(buf, format, p_data) < 1)
+            return false;
     }
     else
     {
         // Small types need a 32-bit buffer to receive the result from scanf()
         int v32;
-        sscanf(buf, format, &v32);
+        if (sscanf(buf, format, &v32) < 1)
+            return false;
         if (data_type == ImGuiDataType_S8)
             *(ImS8*)p_data = (ImS8)ImClamp(v32, (int)IM_S8_MIN, (int)IM_S8_MAX);
         else if (data_type == ImGuiDataType_U8)