tag selector argument with empty tag behaves unexpectedly

Partner Rank:

2

Partner Team Reporting:

Everbloom Studios

Verification builds:

1.15.0.51

Summary:

The selector argument tag with an empty tag as argument @e[tag=] and @e[tag=!] no longer behaves as expected. @e[tag=] is meant to target entities that do NOT have ANY tags. @e[tag=!] is meant to target entities that have AT LEAST ONE tag. This stopped working and now it's as if they're trying to target entities that have an empty string as a tag, which is not possible to add through commands.

Impact:

Content that relies on targeting entities with no tags no longer works.

Repro Steps:

1. Create and join the provided world. There are two pigs. One is tagged with 'foo', the other has no tags.
2. Press both buttons. Each will run a /say command using each of these selector arguments.

Observed Results:

In chat you see:

[tag=] 
[tag=!] Tagged, Not tagged

Expected Results:

In chat you should see:

[tag=] Not tagged
[tag=!] Tagged

Screenshots/Videos attached: Yes/No

No

Regression Builds:

1.14.30.2_rc1