Handle some undefined behavior regarding null pads

rpcs3/Emu/Io/Null/NullPadHandler.h

@@ -12,8 +12,42 @@ public:
 		return true;
 	}
 
-	void init_config(pad_config* /*cfg*/, const std::string& /*name*/) override
+	void init_config(pad_config* cfg, const std::string& /*name*/) override
 	{
+		if (!cfg) return;
+
+		// This profile does not need a save location
+		cfg->cfg_name = "";
+
+		// Reset default button mapping
+		cfg->ls_left.def  = "";
+		cfg->ls_down.def  = "";
+		cfg->ls_right.def = "";
+		cfg->ls_up.def    = "";
+		cfg->rs_left.def  = "";
+		cfg->rs_down.def  = "";
+		cfg->rs_right.def = "";
+		cfg->rs_up.def    = "";
+		cfg->start.def    = "";
+		cfg->select.def   = "";
+		cfg->ps.def       = "";
+		cfg->square.def   = "";
+		cfg->cross.def    = "";
+		cfg->circle.def   = "";
+		cfg->triangle.def = "";
+		cfg->left.def     = "";
+		cfg->down.def     = "";
+		cfg->right.def    = "";
+		cfg->up.def       = "";
+		cfg->r1.def       = "";
+		cfg->r2.def       = "";
+		cfg->r3.def       = "";
+		cfg->l1.def       = "";
+		cfg->l2.def       = "";
+		cfg->l3.def       = "";
+
+		// Apply defaults
+		cfg->from_default();
 	}
 
 	std::vector<std::string> ListDevices() override

rpcs3/Input/ds3_pad_handler.cpp

@@ -244,6 +244,8 @@ std::shared_ptr<ds3_pad_handler::ds3_device> ds3_pad_handler::get_ds3_device(con
 
 void ds3_pad_handler::init_config(pad_config* cfg, const std::string& name)
 {
+	if (!cfg) return;
+
 	// Set this profile's save location
 	cfg->cfg_name = name;
 

rpcs3/Input/ds4_pad_handler.cpp

@@ -136,6 +136,8 @@ ds4_pad_handler::ds4_pad_handler() : PadHandlerBase(pad_handler::ds4)
 
 void ds4_pad_handler::init_config(pad_config* cfg, const std::string& name)
 {
+	if (!cfg) return;
+
 	// Set this profile's save location
 	cfg->cfg_name = name;
 

rpcs3/Input/evdev_joystick_handler.cpp

@@ -49,6 +49,8 @@ evdev_joystick_handler::~evdev_joystick_handler()
 
 void evdev_joystick_handler::init_config(pad_config* cfg, const std::string& name)
 {
+	if (!cfg) return;
+
 	// Set this profile's save location
 	cfg->cfg_name = name;
 

rpcs3/Input/keyboard_pad_handler.cpp

@@ -33,6 +33,8 @@ keyboard_pad_handler::keyboard_pad_handler()
 
 void keyboard_pad_handler::init_config(pad_config* cfg, const std::string& name)
 {
+	if (!cfg) return;
+
 	// Set this profile's save location
 	cfg->cfg_name = name;
 

rpcs3/Input/mm_joystick_handler.cpp

@@ -32,6 +32,8 @@ mm_joystick_handler::~mm_joystick_handler()
 
 void mm_joystick_handler::init_config(pad_config* cfg, const std::string& name)
 {
+	if (!cfg) return;
+
 	// Set this profile's save location
 	cfg->cfg_name = name;
 

rpcs3/Input/xinput_pad_handler.cpp

@@ -83,6 +83,8 @@ xinput_pad_handler::~xinput_pad_handler()
 
 void xinput_pad_handler::init_config(pad_config* cfg, const std::string& name)
 {
+	if (!cfg) return;
+
 	// Set this profile's save location
 	cfg->cfg_name = name;
 

rpcs3/rpcs3qt/pad_settings_dialog.cpp

@@ -1027,8 +1027,8 @@ void pad_settings_dialog::UpdateLabels(bool is_reset)
 			entry.second.text = qstr(entry.second.key);
 		}
 
-		// The button has to contain at least a space, because it would be square'ish otherwise
-		m_padButtons->button(entry.first)->setText(entry.second.text.isEmpty() ? QStringLiteral(" ") : entry.second.text);
+		// The button has to contain at least one character, because it would be square'ish otherwise
+		m_padButtons->button(entry.first)->setText(entry.second.text.isEmpty() ? QStringLiteral("-") : entry.second.text);
 	}
 }
 
@@ -1401,7 +1401,11 @@ void pad_settings_dialog::ChangeProfile()
 	}
 
 	// Load new config
-	m_handler_cfg.load();
+	if (m_handler->m_type != pad_handler::null && !m_handler_cfg.load())
+	{
+		cfg_log.error("Could not load pad config file '%s'", m_handler_cfg.cfg_name);
+		m_handler_cfg.from_default();
+	}
 
 	// Reload the buttons with the new handler and profile
 	ReloadButtons();