Java Edition 17w17a

17w17a is the eighth snapshot released for Java Edition 1.12.

General

 * Advancements


 * Added new advancements
 * New tabs: "The End" and "Nether"
 * New  trigger, with the following conditions:
 * - number of ticks the player is levitating for
 * - distance the player levitated so far
 * Both can be either a range ( and / or  ) or a value
 * New  condition added to the   trigger
 * The value is a feature name as used in the command


 * NBT tags


 * (byte):
 * Defaults to . If set to , loops can be created, where the same command block can run multiple times in one tick.
 * (long):
 * Stores the tick a chain command block was last executed in.
 * (list):
 * Added into the  compound of the player.
 * Within are recipe names that the player has unlocked but not viewed in the crafting helper yet
 * Used for remembering to play the animation for new recipes


 * Sounds


 * New note block sounds
 * = xylophone
 * = bell
 * = flute
 * = chime
 * = guitar


 * New sound effects
 * Parrots
 * Illusioners
 * Casting a fishing rod
 * Reeling in a fishing rod
 * Throwing an eye of ender
 * An eye of ender exploding or popping back into item form
 * Putting ender eye in end portal frames (dinging sound)
 * Completing the end portal and having the portal spawn (evil sound)
 * Boat paddles

Blocks

 * Terracotta
 * It has now unique colors on the map


 * Beds
 * Each leg can now be textured individually

Mobs

 * Illusioners
 * Its blindness spell will only be cast if the regional difficulty is 3 or above.


 * Shulkers
 * Reverted the purple shulker color change from 17w16a.

Command format

 * Added five modifiers to the and  commands:
 * "everything" - all advancements, no specification required (same as "*")
 * "from" - this advancement, its children, and their children, etc.
 * "until" - this advancement, its parent, and its parent, etc.
 * "through" - both of the above
 * "only" - this advancement, and nothing else
 * Examples:
 * Examples:

General

 * Advancements


 * Moved some existing advancements around
 * Advancements can now execute commands when achieved
 * The command written in the rewards section of the advancement will be executed as the player (for example writing  would be equivalent to  )
 * Advancement icons now allow data values
 * Specifically,  has switched from being a string to an object
 * Within it are a required  string (specifying the item ID) and an optional   integer, specifying the metadata of the item
 * The "damage flags object" now contains two new entity objects:
 * - specifies the "owner" of the damage that was dealt
 * - specifies the direct cause of the damage


 * Crafting


 * Optimized the recipe book

Video
Video made by slicedlime:

Trivia

 * 17w17a was previously removed from the launcher for some time, but was added back in September 2018.