Backends: Win32: replace bd != nullptr assert with early out. (#6275)

+ fixed inconsistent use of break vs return 0 in WndProcHandler (had no tangible effect).

backends/imgui_impl_win32.cpp

@@ -582,11 +582,10 @@ static ImGuiMouseSource GetMouseSourceFromMessageExtraInfo()
 IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
 {
     // Most backends don't have silent checks like this one, but we need it because WndProc are called early in CreateWindow().
-    if (ImGui::GetCurrentContext() == nullptr)
-        return 0;
-
+    // We silently allow both context or just only backend data to be nullptr.
     ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData();
-    IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplWin32_Init()?");
+    if (bd == nullptr)
+        return 0;
     ImGuiIO& io = ImGui::GetIO();
 
     switch (msg)
@@ -609,10 +608,10 @@ IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hwnd, UINT msg, WPARA
         }
         POINT mouse_pos = { (LONG)GET_X_LPARAM(lParam), (LONG)GET_Y_LPARAM(lParam) };
         if (msg == WM_NCMOUSEMOVE && ::ScreenToClient(hwnd, &mouse_pos) == FALSE) // WM_NCMOUSEMOVE are provided in absolute coordinates.
-            break;
+            return 0;
         io.AddMouseSourceEvent(mouse_source);
         io.AddMousePosEvent((float)mouse_pos.x, (float)mouse_pos.y);
-        break;
+        return 0;
     }
     case WM_MOUSELEAVE:
     case WM_NCMOUSELEAVE:
@@ -625,7 +624,7 @@ IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hwnd, UINT msg, WPARA
             bd->MouseTrackedArea = 0;
             io.AddMousePosEvent(-FLT_MAX, -FLT_MAX);
         }
-        break;
+        return 0;
     }
     case WM_LBUTTONDOWN: case WM_LBUTTONDBLCLK:
     case WM_RBUTTONDOWN: case WM_RBUTTONDBLCLK:

docs/CHANGELOG.txt

@@ -49,6 +49,9 @@ Other changes:
 - Backends: all backends + demo now call IMGUI_CHECKVERSION() to verify ABI compatibility between caller
   code and compiled version of Dear ImGui. If you get an assert it most likely mean you have a build issue,
   read comments near the assert. (#7568)
+- Backends: Win32: undo an assert introduced in 1.90.6 which didn't allow WndProc
+  handler to be called before backend initialization. Because of how ::CreateWindow()
+  calls in WndProc this is facilitating. (#6275) [@MennoVink]
 
 
 -----------------------------------------------------------------------

imgui_widgets.cpp

@@ -4506,6 +4506,7 @@ bool ImGui::InputTextEx(const char* label, const char* hint, char* buf, int buf_
         const bool is_cancel = Shortcut(ImGuiKey_Escape, id, f_repeat) || (nav_gamepad_active && Shortcut(ImGuiKey_NavGamepadCancel, id, f_repeat));
 
         // FIXME: Should use more Shortcut() and reduce IsKeyPressed()+SetKeyOwner(), but requires modifiers combination to be taken account of.
+        // FIXME-OSX: Missing support for Alt(option)+Right/Left = go to end of line, or next line if already in end of line.
         if (IsKeyPressed(ImGuiKey_LeftArrow))                        { state->OnKeyPressed((is_startend_key_down ? STB_TEXTEDIT_K_LINESTART : is_wordmove_key_down ? STB_TEXTEDIT_K_WORDLEFT : STB_TEXTEDIT_K_LEFT) | k_mask); }
         else if (IsKeyPressed(ImGuiKey_RightArrow))                  { state->OnKeyPressed((is_startend_key_down ? STB_TEXTEDIT_K_LINEEND : is_wordmove_key_down ? STB_TEXTEDIT_K_WORDRIGHT : STB_TEXTEDIT_K_RIGHT) | k_mask); }
         else if (IsKeyPressed(ImGuiKey_UpArrow) && is_multiline)     { if (io.KeyCtrl) SetScrollY(draw_window, ImMax(draw_window->Scroll.y - g.FontSize, 0.0f)); else state->OnKeyPressed((is_startend_key_down ? STB_TEXTEDIT_K_TEXTSTART : STB_TEXTEDIT_K_UP) | k_mask); }