Fix: TextfileWindow called virtual methods before constructor completed. (#11889)

SetStringParameters() was called during widget tree init in the constructor.

Calls within a constructor cannot call the derived classes methods. This would result in invalid data being passed to the string system, which could then crash.

src/help_gui.cpp

@@ -59,6 +59,8 @@ static std::optional<std::string> FindGameManualFilePath(std::string_view filena
 struct GameManualTextfileWindow : public TextfileWindow {
 	GameManualTextfileWindow(std::string_view filename) : TextfileWindow(TFT_GAME_MANUAL)
 	{
+		this->ConstructWindow();
+
 		/* Mark the content of these files as trusted. */
 		this->trusted = true;
 

src/network/network_content_gui.cpp

@@ -43,6 +43,8 @@ struct ContentTextfileWindow : public TextfileWindow {
 
 	ContentTextfileWindow(TextfileType file_type, const ContentInfo *ci) : TextfileWindow(file_type), ci(ci)
 	{
+		this->ConstructWindow();
+
 		auto textfile = this->ci->GetTextfile(file_type);
 		this->LoadTextfile(textfile.value(), GetContentInfoSubDir(this->ci->type));
 	}

src/newgrf_gui.cpp

@@ -560,6 +560,8 @@ struct NewGRFTextfileWindow : public TextfileWindow {
 
 	NewGRFTextfileWindow(TextfileType file_type, const GRFConfig *c) : TextfileWindow(file_type), grf_config(c)
 	{
+		this->ConstructWindow();
+
 		auto textfile = this->grf_config->GetTextfile(file_type);
 		this->LoadTextfile(textfile.value(), NEWGRF_DIR);
 	}

src/script/script_gui.cpp

@@ -631,6 +631,7 @@ struct ScriptTextfileWindow : public TextfileWindow {
 
 	ScriptTextfileWindow(TextfileType file_type, CompanyID slot) : TextfileWindow(file_type), slot(slot)
 	{
+		this->ConstructWindow();
 		this->OnInvalidateData();
 	}
 

src/settings_gui.cpp

@@ -97,6 +97,8 @@ struct BaseSetTextfileWindow : public TextfileWindow {
 
 	BaseSetTextfileWindow(TextfileType file_type, const TBaseSet *baseset, StringID content_type) : TextfileWindow(file_type), baseset(baseset), content_type(content_type)
 	{
+		this->ConstructWindow();
+
 		auto textfile = this->baseset->GetTextfile(file_type);
 		this->LoadTextfile(textfile.value(), BASESET_DIR);
 	}

src/textfile_gui.cpp

@@ -82,13 +82,19 @@ static WindowDesc _textfile_desc(__FILE__, __LINE__,
 );
 
 TextfileWindow::TextfileWindow(TextfileType file_type) : Window(&_textfile_desc), file_type(file_type)
+{
+	/* Init of nested tree is deferred.
+	 * TextfileWindow::ConstructWindow must be called by the inheriting window. */
+}
+
+void TextfileWindow::ConstructWindow()
 {
 	this->CreateNestedTree();
 	this->vscroll = this->GetScrollbar(WID_TF_VSCROLLBAR);
 	this->hscroll = this->GetScrollbar(WID_TF_HSCROLLBAR);
-	this->GetWidget<NWidgetCore>(WID_TF_CAPTION)->SetDataTip(STR_TEXTFILE_README_CAPTION + file_type, STR_TOOLTIP_WINDOW_TITLE_DRAG_THIS);
+	this->GetWidget<NWidgetCore>(WID_TF_CAPTION)->SetDataTip(STR_TEXTFILE_README_CAPTION + this->file_type, STR_TOOLTIP_WINDOW_TITLE_DRAG_THIS);
 	this->GetWidget<NWidgetStacked>(WID_TF_SEL_JUMPLIST)->SetDisplayedPlane(SZSP_HORIZONTAL);
-	this->FinishInitNested(file_type);
+	this->FinishInitNested(this->file_type);
 
 	this->DisableWidget(WID_TF_NAVBACK);
 	this->DisableWidget(WID_TF_NAVFORWARD);

src/textfile_gui.h

@@ -23,8 +23,6 @@ struct TextfileWindow : public Window, MissingGlyphSearcher {
 	Scrollbar *vscroll;              ///< Vertical scrollbar.
 	Scrollbar *hscroll;              ///< Horizontal scrollbar.
 
-	TextfileWindow(TextfileType file_type);
-
 	void UpdateWidgetSize(WidgetID widget, Dimension *size, [[maybe_unused]] const Dimension &padding, [[maybe_unused]] Dimension *fill, [[maybe_unused]] Dimension *resize) override;
 	void OnClick([[maybe_unused]] Point pt, WidgetID widget, [[maybe_unused]] int click_count) override;
 	void DrawWidget(const Rect &r, WidgetID widget) const override;
@@ -42,6 +40,9 @@ struct TextfileWindow : public Window, MissingGlyphSearcher {
 	virtual void LoadTextfile(const std::string &textfile, Subdirectory dir);
 
 protected:
+	TextfileWindow(TextfileType file_type);
+	void ConstructWindow();
+
 	struct Line {
 		int top{0};                  ///< Top scroll position in visual lines.
 		int bottom{0};               ///< Bottom scroll position in visual lines.