[MC-87252] Optional tags gets removed when set to false/0/empty

The Bug

When the CustomNameVisible tag is set to false (0b) the game automatically removes the tag from the NBT data of the Entity. This also affects newly summoned Entities which do not have it by default if it is not true.
This is a big problem as you cannot test for it then.

Steps to Reproduce

Summon a husk with its "CustomNameVisible" tag set to "0b".
```
/summon minecraft:husk ~ ~ ~ {CustomNameVisible:0b}
```
Use the data command on the husk to inspect the value of its "CustomNameVisible" tag.
```
/data get entity @e[type=minecraft:husk,limit=1,sort=nearest] CustomNameVisible
```
❌ → Notice how the error message, "Found no elements matching CustomNameVisible" is displayed in the chat, therefore indicating that optional NBT data tags get removed when set to "0", "false", or "empty".

Expected Behavior

The expected behavior would be that optional NBT data tags would not get removed when set to "0", "false", or "empty".

Linked issues

is duplicated by 1

MC-117782 Adult zombies and zombie pigmen missing the "IsBaby" tag Resolved

relates to 1

MC-80975 Tags in Pose of armor_stand are removed when containing default values Reopened

Attachments

MC-87252.mp4

Comments 12

Anon Ymus 2015-08-25T02:27:23Z

Confirmed.

marcono1234 2015-11-25T18:43:51Z

Might be intended because this tag is optional and its default value is 0.
Moreover the same seems to happen with the Silent tag

user-f2760 2015-11-25T18:50:17Z

happens with all optional tags, IsBaby, ~~IsVillager, VillagerProfession~~ and NoAI are also effected.
in my opinion these should exist if you specify them in the summon/entitydata, regardless of value

Calvin 2017-05-21T18:05:09Z

Tested it further, /summon minecraft:zombie ~ ~ ~ {IsBaby:0} actually does guarantee that it won't be a baby (while normally there's a small chance that it will be), which is further evidence that this is a bug.

marcono1234 2017-05-21T19:50:46Z

@@unknown no this is no evidence for that. If you just provide an empty compound it would already prevent the randomization.

2 more comments

j_p_smith 2020-06-21T16:53:38Z

Related to MC-80975.

KirbAvion 2020-07-09T05:54:50Z

Confirmed for 1.16.1.

Avoma 2021-09-26T08:15:49Z

I am able to confirm this behavior in both 1.17.1 and 21w38a. Here are some extra details regarding this problem.

The Bug:

Optional NBT data tags get removed when set to "0", "false", or "empty".

Steps to Reproduce:

Summon a husk with its "CustomNameVisible" tag set to "0b".

/summon minecraft:husk ~ ~ ~ {CustomNameVisible:0b}

Use the data command on the husk to inspect the value of its "CustomNameVisible" tag.

/data get entity @e[type=minecraft:husk,limit=1,sort=nearest] CustomNameVisible

→ ❌ Notice how the error message, "Found no elements matching CustomNameVisible" is displayed in the chat, therefore indicating that optional NBT data tags get removed when set to "0", "false", or "empty".

Expected Behavior:

The expected behavior would be that optional NBT data tags would not get removed when set to "0", "false", or "empty".

user-f2760 2022-02-09T09:22:50Z

Can confirm for 1.18.1 and 22w05.

Avoma 2022-05-14T13:21:07Z

Can confirm in 1.18.2 and 22w19a.