Fix love.event.quit causing crashes and other bad behaviour if a Canvas is active. Resolves issue #1395.

src/modules/graphics/opengl/Canvas.cpp

@@ -271,11 +271,14 @@ bool Canvas::loadVolatile()
 
 void Canvas::unloadVolatile()
 {
-	// This is a bit ugly, but we need some way to destroy the cached FBO
-	// when this Canvas' texture is destroyed.
-	auto gfx = Module::getInstance<Graphics>(Module::M_GRAPHICS);
-	if (gfx != nullptr)
-		gfx->cleanupCanvas(this);
+	if (fbo != 0 || renderbuffer != 0 || texture != 0)
+	{
+		// This is a bit ugly, but we need some way to destroy the cached FBO
+		// when this Canvas' texture is destroyed.
+		auto gfx = Module::getInstance<Graphics>(Module::M_GRAPHICS);
+		if (gfx != nullptr)
+			gfx->cleanupCanvas(this);
+	}
 
 	if (fbo != 0)
 		gl.deleteFramebuffer(fbo);

src/modules/window/sdl/Window.cpp

@@ -77,7 +77,7 @@ Window::Window()
 
 Window::~Window()
 {
-	close();
+	close(false);
 
 	graphics.set(nullptr);
 
@@ -413,7 +413,7 @@ bool Window::setWindow(int width, int height, WindowSettings *settings)
 		graphics.set(Module::getInstance<graphics::Graphics>(Module::M_GRAPHICS));
 
 	if (graphics.get() && graphics->isCanvasActive())
-		throw love::Exception("setMode cannot be called while a Canvas is active in love.graphics.");
+		throw love::Exception("love.window.setMode cannot be called while a Canvas is active in love.graphics.");
 
 	WindowSettings f;
 
@@ -640,11 +640,16 @@ void Window::getWindow(int &width, int &height, WindowSettings &newsettings)
 }
 
 void Window::close()
+{
+	close(true);
+}
+
+void Window::close(bool allowExceptions)
 {
 	if (graphics.get())
 	{
-		if (graphics->isCanvasActive())
-			throw love::Exception("close cannot be called while a Canvas is active in love.graphics.");
+		if (allowExceptions && graphics->isCanvasActive())
+			throw love::Exception("love.window.close cannot be called while a Canvas is active in love.graphics.");
 
 		graphics->unSetMode();
 	}
@@ -674,7 +679,7 @@ bool Window::setFullscreen(bool fullscreen, Window::FullscreenType fstype)
 		return false;
 
 	if (graphics.get() && graphics->isCanvasActive())
-		throw love::Exception("setFullscreen cannot be called while a Canvas is active in love.graphics.");
+		throw love::Exception("love.window.setFullscreen cannot be called while a Canvas is active in love.graphics.");
 
 	WindowSettings newsettings = settings;
 	newsettings.fullscreen = fullscreen;

src/modules/window/sdl/Window.h

@@ -121,6 +121,8 @@ public:
 
 private:
 
+	void close(bool allowExceptions);
+
 	struct ContextAttribs
 	{
 		int versionMajor;