{{Infobox version
| title = Minecraft 17w45a
| edition = Java
| image = 17w45a.png
| image2 = Java Edition 17w45a.png
| type = Snapshot
| date = November 8, 2017
| parent = 1.13
| clienthash = 42c93d04a82371094d9a4a844c932b8db45d3a40
| jsonhash = c3a0cc0ba68d054095dc52010b7b71a35b9ab17f
| serverhash = 471b2dfa12e4df234057159ce5ee8320da3c84c1
| prevparent = 1.12.2
| prev = 17w43b
| next = 17w45b
| nextparent = 1.13.1
}}<onlyinclude>

'''17w45a''' is the third [[snapshot]] for [[Java Edition 1.13]], released on November 8, 2017<ref>{{snap|17w45a|November 8, 2017}}</ref>, which completely overhauled the command system.

== Additions ==
=== Command format ===
; General
* A command UI when typing commands in the chat.
** Different components of commands are displayed in different colors.
** Errors are displayed in red without having to run the command.
* An <code>nbt</code> argument in target selectors.
* A new command parsing library called [[Brigadier]].

== Changes ==
=== Mobs ===
; [[Horse]]s
[[File:Black Horse Revision 2.gif|48px]] [[File:Brown Horse Revision 2.gif|48px]] [[File:Chestnut Horse Revision 2.gif|48px]] [[File:Creamy Horse Revision 2.gif|48px]] [[File:Darkbrown Horse Revision 2.gif|48px]] [[File:Gray Horse Revision 2.gif|48px]] [[File:White Horse Revision 2.gif|48px]]<br>
[[File:Baby Black Horse Revision 2.gif|48px]] [[File:Baby Brown Horse Revision 2.gif|48px]] [[File:Baby Chestnut Horse Revision 2.gif|48px]] [[File:Baby Creamy Horse Revision 2.gif|48px]] [[File:Baby Darkbrown Horse Revision 2.gif|48px]] [[File:Baby Gray Horse Revision 2.gif|48px]] [[File:Baby White Horse Revision 2.gif|48px]]
* The model has been simplified to be more consistent with other mobs.
* Some animations like opening its mouth when grazing has been removed from the model as well, and the saddle animation is changed slightly.

=== Command format ===
; General
* Commands and functions are much faster and more efficient.
* Most commands are now more case-sensitive. Lowercase is preferable wherever possible.
** For example, this is no longer allowed: {{cmd|scoreboard ObJeCtIvEs ...}}
* The output signal of a command block used to be its "success count", but now is its "result".

; [[Argument types#minecraft:block_state|Block argument type]]
* Wherever a <code><block></code>, optionally <code><nowiki>[<data>]</nowiki></code> and optionally <code>[<nbt>]</code> was required, it is now a single <code><block></code> argument that looks like this:
** <code>stone</code>
** <code>minecraft:redstone_wire[power=15,north=up,south=side]</code>
** <code>minecraft:jukebox{RecordItem:{...}}</code>
** <code>minecraft:furnace[facing=north]{BurnTime:200}</code>
* ID is required (though just as before, if namespace isn't set it defaults to <code>minecraft:</code>).
* States are inside <code>[]</code>, comma-separated and must be properties/values supported by the blocks. They are optional.
** <code>minecraft:stone[doesntexist=purpleberry]</code> is a syntax error, because <code>stone</code> does not have <code>doesntexist</code>.
** <code>minecraft:redstone_wire[power=tuesday]</code> is a syntax error, because <code>redstone_wire</code>'s <code>power</code> is a number between 0 and 15.
* An optional tag is inside {}, and works just like the [[player]] would expect.
* In the context of "conditions"/testing for blocks, only the states the player provided are tested.
** If the player tests <code>redstone_wire[power=15]</code>, it only checks power but ignores other states such as <code>north</code>.
* In the context of setting blocks, any states the player provided are set but anything missed out defaults depending on the block.
** If the player set <code>redstone_wire[power=15]</code>, it sets <code>power</code> to 15 but <code>north</code> is a default value (in this case, set to <code>none</code>).
* There is no such thing as block data value in 1.13, but either a different block or a state.

=== Commands ===
; {{cmd|?}}
* Removed in favor of {{cmd|help}}.

; {{cmd|advancement}}
* Removed {{cmd|advancement test}} in favor of entity selectors.

; {{cmd|clear}}
* The syntax of {{cmd|clear}} has changed.
** {{cmd|clear [<target>] [<item>] [<data>] [<count>] [<nbt>]}} becomes {{cmd|clear [<target>] [<item>] [<count>]}}.
** See the item argument type for more details.
** <code>[<nowiki><data></nowiki>]</code> has been removed in preparation for the [[1.13/Flattening|flattening]], item data is no longer a thing and item damage values are moved into NBT.

; {{cmd|clone}}
* The syntax of {{cmd|clone}} has been changed.
** {{cmd|clone <begin> <end> <destination> filtered [force{{!}}move{{!}}normal] [<block>] [<data>]}} becomes {{cmd|clone <begin> <end> <destination> filtered [<block>] [force{{!}}move{{!}}normal]}}.
** {{cmd|clone <begin> <end> <destination> [replace{{!}}masked] [force{{!}}move{{!}}normal] [<block>] [<data>]}} becomes {{cmd|clone <begin> <end> <destination> [replace{{!}}masked] [force{{!}}move{{!}}normal]}}.

; {{cmd|defaultgamemode}} and {{cmd|gamemode}}
* Now only accepts string IDs, not shorthand or numeric.
** {{cmd|gamemode 2}} becomes {{cmd|gamemode adventure}}.
** {{cmd|defaultgamemode sp}} is now {{cmd|defaultgamemode spectator}}.

; {{cmd|difficulty}}
* {{cmd|difficulty [<value>]}} now only accepts string IDs, not shorthand or numeric.
** {{cmd|difficulty 2}} is now {{cmd|difficulty normal}}.
** {{cmd|difficulty p}} is now {{cmd|difficulty peaceful}}.
* The player can now query for the current difficulty by using {{cmd|difficulty}} without any arguments.

; {{cmd|effect}}
* The syntax of {{cmd|effect}} has been split off, to avoid ambiguity.
** {{cmd|effect <entity> <effect>}} is now {{cmd|effect give <entity> <effect>}}.
** {{cmd|effect <entity> clear}} is now {{cmd|effect clear <entity> [<effect>]}}.
* Giving an effect now fails if it didn't actually do anything.
** Some mobs are immune (for example an [[ender dragon]]).
** Stronger existing effects prevent new weaker ones.

; {{cmd|enchant}}
* Removed from the game, in order to be replaced by the planned {{cmd|modifyitem|link=Commands/item#History}} command (later reverted in [[18w06a]]).

; {{cmd|execute}}
* The syntax of {{cmd|execute}} has been split off.
** Modifier sub-commands can change how the command is ran:
*** {{cmd|execute as <entity> <chained command>}} executes a command using the entity <code><entity></code> (but doesn't change position).
*** {{cmd|execute at <entity> <chained command>}} executes a command using the position of <code><entity></code> (but doesn't change entity).
*** {{cmd|execute offset <pos> <chained command>}} executes a command using the position of <code><pos></code>.
*** {{cmd|execute align <axes> <chained command>}} executes a command after aligning the current position to the block grid (rounding down), <code><axes></code> is any combination of <code>x</code> <code>y</code> and <code>z</code> (for example: <code>x</code>,<code>xz</code>,<code>zyx</code> and <code>yz</code>).
**** Examples:
***** <code>x=-1.8,y=2.3,z=5.9</code> using <code>x</code> becomes <code>x=-2,y=2.3,z=5.9</code>.
***** <code>x=2.4,y=-1.1,z=3.8</code> using <code>yxz</code> becomes <code>x=2,y=-2,z=3</code>.
** Conditional sub-commands can let the player prevent the command from running at all:
*** {{cmd|execute (if{{!}}unless) block <pos> <block> <chained command>}} executes a command if (or unless) <code><pos></code> matches <code><block></code>.
*** {{cmd|execute (if{{!}}unless) blocks <begin> <end> <destination> (all{{!}}masked) <chained command>}} executes a command if (or unless) the region between <code><start></code> and <code><end></code> matches <code><destination></code>.
*** {{cmd|execute (if{{!}}unless) entity <entity> <chained command>}} executes a command if (or unless) <code><entity></code> exists (returns 1 or more entities).
*** {{cmd|execute (if{{!}}unless) score <target> <targetObjective> (<nowiki><|<=|=|>=|></nowiki>) <nowiki><source></nowiki> <sourceObjective> <chained command>}} executes a command if (or unless) <code><target></code>'s score relates to <code><nowiki><source></nowiki></code>'s score based on the chosen criterion.
** As replacement for {{cmd|stats}}, a new sub-command <code>store</code> lets the player store the result or success of a command somewhere:
*** {{cmd|execute store (result{{!}}success) <name> <objective> <chained command>}}.
*** <code>result</code> is the result of a command, which replaces these old stats: <code>AffectedBlocks</code>, <code>AffectedEntities</code>, <code>AffectedItems</code>, <code>QueryResult</code>.
*** <code>success</code> is how many times the command was successful. This is usually <code>0</code> or <code>1</code>, but if the command split up (for example <code>as @a</code>) then it may be more than <code>1</code>. This replaces <code>SuccessCount</code>.
*** The value is stored into the scoreboard under <code><name></code> and <code><objective></code>.
*** The <code>objective</code> must exist, but unlike with {{cmd|stats}}, the player doesn't need to set an initial value for <code><name></code>.
*** The value is stored when the full command has finished executing.
*** If a command isn't successful (<code>success</code> is <code>0</code>), <code>result</code> is always set to <code>0</code>.
*** It is made clear what the expected result of each command is.
** The player can chain all sub-commands together.
*** After every sub-command, the player needs to write another sub-command.
*** When the player is done with chaining sub-commands, <code>run</code> lets players write the actual command to be executed.
**** <code>/</code> is no longer allowed before the command.
*** {{cmd|execute as somebody at somebody run say hi}}.
** Example of old commands:
*** {{cmd|execute @e ~ ~ ~ detect ~ ~ ~ stone 0 say Stone!}} is now {{cmd|execute as @e at @s if block ~ ~ ~ stone run say Stone!}}
*** {{cmd|execute @e ~ ~ ~ detect ~ ~ ~ grass 0 summon pig}} is now {{cmd|execute at @e if block ~ ~ ~ grass run summon pig}}.
*** {{cmd|execute @e ~ ~ ~ say Hello!}} is now {{cmd|execute as @e run say Hello!}}

; {{cmd|experience}}
* {{cmd|xp}} is now an alias for {{cmd|experience}}.
* Split up into 3 different subcommands:
** {{cmd|experience add <players> <amount> [points{{!}}levels]}}
*** Adds <code><amount></code> of either points or levels to the target <code><players></code> (defaults to points).
*** Adding points can cause players to level up, as usual.
*** Negative numbers are supported, to subtract points instead.
*** Subtracting points can cause players to level down.
** {{cmd|experience set <players> <amount> [points{{!}}levels]}}.
*** Sets <code><amount></code> of either points or levels on the target <code><players></code> (defaults to points).
*** The player cannot set more points than their current level allows.
*** When changing levels, the points stay at the same percentage as the previous level.
** {{cmd|experience query <player> (points{{!}}levels)}}.
*** Returns either the number of points or levels on the given <code><player></code>.

; {{cmd|fill}}
* The syntax of {{cmd|fill}} has been changed.
** {{cmd|fill <x y z> <xt yt zt> <block> <data> replace [<replaceBlock>] [<replaceData>]}} is now {{cmd|fill <x y z> <xt yt zt> <block> replace [<filter>]}}.
** {{cmd|fill <x y z> <xt yt zt> <block> [<data>] [destroy{{!}}hollow{{!}}keep{{!}}outline{{!}}replace] [<nbt>]}} is now {{cmd|/fill <x y z> <xt yt zt> <block> [destroy{{!}}hollow{{!}}keep{{!}}outline{{!}}replace]}}.

; {{cmd|function}}
* {{cmd|function}} no longer accepts <code>[if|unless] <entity></code> arguments.
** This has been moved into {{cmd|execute}}.
** {{cmd|function foo if @e}} is now {{cmd|execute if entity @e run function foo}}.

; {{cmd|gamerule}}
* {{cmd|gamerule}} no longer accepts unknown rules ("custom gamerules").
** The player can use [[Function (Java Edition)|function]]s or [[scoreboard]]s as replacements, with no loss of functionality.
** Existing custom gamerules are not accessible. Only built-in rules are available.
* Values to {{cmd|gamerule}} are now type checked (giving a string if it wants an int is a very obvious error).

; {{cmd|give}}
* The syntax of {{cmd|give}} has changed.
** {{cmd|give <players> <item> [<count>] [<data>] [<nbt>]}} is now {{cmd|give <players> <item> [<count>]}}.
** See the item argument type for more details.
** <code>[<nowiki><data></nowiki>]</code> has been removed in preparation for the [[1.13/Flattening|flattening]], item data is no longer a thing and item damage values are moved into NBT.

; {{cmd|kill}}
* A <code>target</code> is now mandatory.

; {{cmd|locate}}
* The y-coordinate is now returned as <code>64</code> instead of <code>?</code>.
* The <code>result</code> of the command, used by {{cmd|execute store}}, is the absolute distance to the structure.

; {{cmd|op}}
* Now allows target selectors besides names.

; {{cmd|particle}}
* The <code><params></code> argument has been removed, instead the parameters for particles like <code>blockcrack</code> can be specified right after the <code><name></code> argument using the new block argument.
** {{cmd|particle blockcrack stone <nowiki>[variant=smooth_granite]</nowiki> ~ ~ ~ 0 0 0 0 1}}.
* The particle names have been converted to lowercase and optionally have a namespace.

; {{cmd|publish}}
* Added an optional <code>port</code> argument.

; {{cmd|replaceitem}}
* The syntax of {{cmd|replaceitem}} has changed.
** {{cmd|replaceitem block <pos> <slot> <item> [<count>] [<data>] [<nbt>]}} is now {{cmd|replaceitem block <pos> <slot> <item> [<count>]}}.
** {{cmd|replaceitem entity <target> <slot> <item> [<count>] [<data>] [<nbt>]}} is now {{cmd|replaceitem entity <target> <slot> <item> [<count>]}}.
** See the item argument type for more details.
** <code>[<nowiki><data></nowiki>]</code> has been removed in preparation for the [[1.13/Flattening|flattening]], item data is no longer a thing and item damage values are moved into NBT.
* The <code>slot</code> argument no longer requires <code>slot.</code>.
** For example, <code>slot.hotbar.1</code> now is <code>hotbar.1</code>.

; {{cmd|scoreboard}}
* {{cmd|scoreboard}} had <code>[<dataTag>]</code> removed from its commands in favor of the <code>nbt</code> argument in entity selectors.
* {{cmd|scoreboard players tag}} and {{cmd|scoreboard teams}} removed. Replaced by {{cmd|tag}} and {{cmd|team}} respectively.
* {{cmd|scoreboard players test}} removed in favor of {{cmd|execute (if{{!}}unless) score}}, entity selectors and {{cmd|scoreboard players get <target> <objective>}}.

; {{cmd|setblock}}
* The syntax of {{cmd|setblock}} has changed.
** {{cmd|setblock <pos> <block> [<data>] [<mode>] [<nbt>]}} is now {{cmd|setblock <pos> <block> [<mode>]}}.
** See the block argument type changes above for more details.

; {{cmd|stats}}
* Removed. Now part of {{cmd|execute}}.
* The new {{cmd|execute}} one is not a direct replacement, the behavior has changed:
** It is now per-command, instead of per-entity or per-block.
** There's only <code>result</code> and <code>success</code>, which covers all the old stat types.

; {{cmd|stopsound}}
* <code>*</code> can now be used instead of <code>source</code> to stop all sounds with a certain name, across all sources.

; {{cmd|tag}}
* Replaces {{cmd|scoreboard players tag}}.
* Keeps the same syntax.
** {{cmd|tag <players> add <tag>}} to add <code><tag></code> to <code><players></code>.
** {{cmd|tag <players> remove <tag>}} to remove <code><tag></code> from <code><players></code>.
** {{cmd|tag <players> list}} to list all tags on <code>players</code>.

; {{cmd|team}}
* Replaces {{cmd|scoreboard teams}}.
* Keeps the same syntax.
** {{cmd|team add <team> [<displayname>]}}
** {{cmd|team empty <team>}}
** {{cmd|team join <team> [<members>]}}
** {{cmd|team leave [<members>]}}
** {{cmd|team list [<team>]}}
** {{cmd|team option <team> <option> <value>}}

; {{cmd|testfor}}, {{cmd|testforblock}} and {{cmd|testforblocks}}
* Removed and now part of {{cmd|execute}}.

; {{cmd|toggledownfall}}
* Removed in favor of {{cmd|weather}}.

; {{cmd|tp}} and {{cmd|teleport}}
* {{cmd|tp}} is now an alias of {{cmd|teleport}} (much like {{cmd|w}}, {{cmd|msg}} and {{cmd|tell}}).
* Coordinates are now relative to the executor, as with all other commands.
* The syntax of {{cmd|tp}} remains, but with the behavior of {{cmd|teleport}}.

; {{cmd|trigger}}
* {{cmd|trigger <objective>}} is a new syntax as a shortcut for {{cmd|trigger <objective> add 1}}.

; {{cmd|weather}}
* If the player doesn't specify a time, it now defaults to 5 minutes (previously random).

; [[Item]]s
* Wherever an <code><item></code>, optionally <code><nowiki>[<data>]</nowiki></code> and optionally <code>[<nbt>]</code> was required, it is now a single <code><item></code> argument that looks like this:
** <code>stone</code>
** <code>minecraft:stick{display:{Name:"Stick of Untruths"}}</code>
* ID is required (though just as before, if namespace isn't set it defaults to <code>minecraft:</code>).
* An optional tag is inside {}, and works just like the [[player]] would expect.
** Any other information is either a separate item or a property in NBT.

; [[Target selector]]s
* More error handling has been introduced.
* Arguments may now be quoted.
** Things like <code>limit=0</code>, <code>level=-10</code>, <code>gamemode=purple</code> are not allowed.
* There's no longer a "min" and "max" separate values, we instead support ranges.
** <code>level=10</code> is level 10.
** <code>level=10..12</code> is level 10, 11 or 12.
** <code>level=5..</code> is anything level 5 or above.
** <code>level=..15</code> is anything level 15 or below.
* The arcane shorthand names have been renamed.
** <code>m</code> -> <code>gamemode</code>
** <code>l</code> or <code>lm</code> -> <code>level</code>
** <code>r</code> or <code>rm</code> -> <code>distance</code>
** <code>rx</code> or <code>rxm</code> -> <code>x_rotation</code>
** <code>ry</code> or <code>rym</code> -> <code>y_rotation</code>
** <code>c</code> -> <code>limit</code>
* <code>x</code>, <code>y</code>, <code>z</code>, <code>distance</code>, <code>x_rotation</code>, <code>y_rotation</code> are now doubles and allow values like <code>12.34</code>.
** <code>x</code> and <code>z</code> are no longer center-corrected.
*** This means <code>x=0</code> no longer equates to <code>x=0.5</code>.
* <code>gamemode</code> (previously <code>m</code>) no longer allows numerical or shorthand IDs.
* <code>limit</code> (was <code>c</code>) No longer allows negative values.
** Use <code>sort=furthest</code> instead.
* The <code>name</code> argument now supports spaces (as long as it is quoted).
* Multiple of the same argument in target selectors is now possible.
** <code>tag=foo,tag=bar,tag=!baz</code> matches someone with <code>foo</code>, <code>bar</code> and not <code>baz</code>.
** <code>type=!cow,type=!chicken</code> matches something that isn't a cow and isn't a chicken.
** <code>type=cow,type=chicken</code> isn't allowed, because something cannot both be a cow and chicken.
* The player can specify the sorting.
** <code>sort=nearest</code> is the old default, sorting by distance (default for <code>@p</code>).
** <code>sort=furthest</code> is the reverse of that (previously the player would use <code>c=-5</code> for this).
** <code>sort=random</code> for random sorting (default for <code>@r</code>).
** <code>sort=arbitrary</code> is a new option to not sort the result (default for <code>@e</code>, <code>@a</code>).
* Specifying scores now looks like <code>scores={foo=1,bar=1..5}</code>.
* The player can test for advancements with <code>advancements={foo=true,bar=false,custom:something={criterion=true}}</code>.
** <code>true</code> for "they completed the advancement", <code>false</code> for "they have not completed the advancement".
** Alternatively, pass a block of specific criteria to test for (again, <code>true</code>/<code>false</code>).

== Fixes ==
{{fixes|fixedin=17w45a|prefix=Minecraft
|;old
|32972|{{cmd|summon}} accepts arguments that it will ignore.
|59511|{{cmd|Tellraw}} has an incomplete error message when key determining text to display is missing.
|69042|{{cmd|summon}} coordinate syntax should be different.
|80856|Command syntax inconsistencies.
|80893|Sender bias (<code>c{{=}}1</code>) applies when sender is not the closest entity to specified x/y/z origin.
|80928|Player sits too ahead when riding a (skeleton/zombie) horse/donkey/mule.
|85394|Spawning 'crit' particle with speed >100 causes an extreme lag spike.
|87365|Incorrect syntax for scoreboard players tag.
|87559|{{cmd|Gamerule}} missing indicator for affected gamerule.
|91459|{{cmd|setblock}} at Y{{=}}256 shows unique message compared to using other outside-world setblock commands/Using {{cmd|setblock}} at Y>256 says max building height is 256.
|101113|{{cmd|playsound}} command is not validating arguments correctly.
|101135|Confusing error message for relative coordinates with too high numbers.
|102682|Horseshoes and horse leg separated.
|105820|Relative decimal coordinates with block related commands are inconsistent.
|115957|Advancements, loot tables, resource packs and world folders don't require lower case.
|116045|{{cmd|banlist}} command treats any non "ips" argument as "players".
|118308|Narrator is toggled when typing in some text fields.
|118565|Four negative signs in a selector which only has the potential to select one entity will attempt to parse as a UUID and fail.
|119142|You can't use multiple tags in a selector.
|122085|Generating server icon leaks encoded data buffer.
|128561|<code>CommandBase.commandListener</code> retains old server reference, preventing garbage collection.
|;dev
|121281|Scrollbar in the creative and server menu isn't working with mouse.
|121283|Underwater and in lava overlay is missing.
|121284|Resource pack and world folder buttons don't work.
|121288|Cinematic camera doesn't work properly.
|121302|"Direct connect" button enabled/disabled at wrong times.
|121314|Video settings slider text "FS Resolution" doesn't fit.
|121328|GUI scales incorrectly.
|121329|Pressing "chat" key no longer selects search in creative inventory/recipe book.
|121334|<nowiki>[1-9]</nowiki> in creative inventory search tab sends additional keypress to search bar.
|121396|WASD keys in a weird order.
|121418|Crash when trying to paste non-string clipboard content.
|121419|Click and hover events are offset in chat.
|121421|Pressing enter in the name or seed field on the create world dialog no longer creates the world.
|121456|Chunks disappearing after switching windows in fullscreen mode.
|121468|Statistics can no longer be ordered by clicking icons.

|;previous
|121517|Fullscreen button will not make game fullscreen.
|121587|{{cmd|reload}} feedback says it reloaded loot tables, advancements and functions instead of just saying data packs.
}}</onlyinclude>

== Video ==
Video made by [[slicedlime]]: 
{{yt|-lWtt3gooB4}}

== References ==
{{reflist}}

== Navigation ==
{{Navbox Java Edition versions|1.1x}}

[[de:17w45a]]
[[es:Java Edition 17w45a]]
[[fr:Édition Java 17w45a]]
[[ja:Java Edition 17w45a]]
[[nl:17w45a]]
[[pt:Edição Java 17w45a]]
[[ru:17w45a (Java Edition)]]
[[zh:17w45a]]