Minecraft crashes with this command.

Moderator note: Malformed command

The correct command is

summon Villager ~ ~2 ~ {Offers:{Recipes:[{buy:{id:"minecraft:emerald",Count:1},sell:{id:"minecraft:diamond_shovel",tag:{CanDestroy:["gravel"],Count:1}},maxUses:1,uses:0}]}}

However, we think that this is still an issue as the game should print an error message rather than crashing.

Minecraft crashes when I try to buy something from a villager with this command:

summon Villager -101.5 68 193 {Offers:{Recipes:[{buy:{id:minecraft:emerald,Count:1},sell:{id:diamond_shovel{CanDestroy:["gravel"]},Count:1},maxUses:1,uses:0}]}}

To replicate:
1. Create command block and input this command:

summon Villager ~1 ~1 ~1 {Offers:{Recipes:[{buy:{id:minecraft:emerald,Count:1},sell:{id:diamond_shovel{CanDestroy:["gravel"]},Count:1},maxUses:1,uses:0}]}}

2. Activate the command block.
3. Right click the villager.
3. Put an emerald in the space provided.

Description: Updating screen events

java.lang.NullPointerException: Updating screen events
	at abe.j(SourceFile:158)
	at abe.a(SourceFile:87)
	at abk.c(SourceFile:81)
	at aac.a(SourceFile:237)
	at bmv.a(SourceFile:338)
	at bgh.a(SourceFile:513)
	at bgh.b(SourceFile:484)
	at bfc.d(SourceFile:248)
	at bfc.k(SourceFile:219)
	at bby.p(SourceFile:1352)
	at bby.aj(SourceFile:774)
	at bby.f(SourceFile:728)
	at net.minecraft.client.main.Main.main(SourceFile:154)