Regex patterns not enforced in browser

[FutureTense]

The problem

As I was writing this, the “your topic is similar to…” nag screen showed someone else had the same problem. Turns out it was me! But the problem still remains.

1. From the Helpers screen, I click “add helper”, then click “Text”
2. I name the field youbigdummy ^{I miss Redd Foxx, God rest his smutty soul}
3. In the regex pattern field I enter [a-fA-F0-9]* and then click Create
4. From the helpers screen again, I filter on “dummy”, and see my new string and click on it. I click the hamburger icon at the top right and see the value is (empty value).
5. I click the field and can enter anything, specifically things that violate the regex. Such as ?!%!!,.*)
6. Like the previous step, I can enter that value into a lovelace form, like:

type: entities
entities:
  - entity: input_text.youbigdummy
show_header_toggle: false

What needs to be done to enforce the regex pattern?

What is version of Home Assistant Core has the issue?

Home Assistant 2021.9.6

What was the last working version of Home Assistant Core?

No response

What type of installation are you running?

Home Assistant Container

Integration causing the issue

n/a

Link to integration documentation on our website

https://www.home-assistant.io/integrations/input_text/

Example YAML snippet

No response

Anything in the logs that might be useful for us?

No response

Additional information

No response

[probot-home-assistant]

input_text documentation
input_text source
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[probot-home-assistant]

Hey there @home-assistant/core, mind taking a look at this issue as it has been labeled with an integration (input_text) you are listed as a code owner for? Thanks!
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