Items in saved creative toolbars upgrade improperly from 1.12.2 to 1.13-pre1

The bug

In the saved creative toolbar, items with new IDs are lost upon upgrading. Enchantments and custom names are lost as well.

Doesn't affect the hotbar.

21:46:47	xo	Something went wrong upgrading!
java.lang.IllegalArgumentException: Unknown type: hotbar
	at adu.a(SourceFile:78)
	at adu$$Lambda$298/2075981552.apply(Unknown Source)
	at java.util.HashMap.computeIfAbsent(HashMap.java:1118)
	at adu.b(SourceFile:77)
	at xm.a(SourceFile:26)
	at xo.a(SourceFile:37)
	at xn.a(SourceFile:18)
	at xn.a(SourceFile:9)
	at cik.b(SourceFile:45)
	at cik.a(SourceFile:70)
	at cnl.b(SourceFile:479)
	at cnl.mouseReleased(SourceFile:456)
	at cis.a(SourceFile:69)
	at cis$$Lambda$918/80668955.run(Unknown Source)
	at cmh.a(SourceFile:429)
	at cis.a(SourceFile:69)
	at cis$$Lambda$693/1104285446.invoke(Unknown Source)
	at org.lwjgl.glfw.GLFWMouseButtonCallbackI.callback(GLFWMouseButtonCallbackI.java:23)
	at org.lwjgl.system.JNI.invokeV(Native Method)
	at org.lwjgl.glfw.GLFW.glfwPollEvents(GLFW.java:2520)
	at cja.a(SourceFile:286)
	at ciq.c(SourceFile:839)
	at ciq.a(SourceFile:379)
	at net.minecraft.client.main.Main.main(SourceFile:144)