# Adding an invalid tag to a topic creates a whisper post
**URL:** https://meta.discourse.org/t/adding-an-invalid-tag-to-a-topic-creates-a-whisper-post/383286
**Category:** Bug
**Tags:** pr-welcome, tags
**Created:** [September 19, 2025, 1:41pm UTC](https://meta.discourse.org/t/adding-an-invalid-tag-to-a-topic-creates-a-whisper-post/383286 "2025-09-19T13:41:58Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@tvavrda](https://meta.discourse.org/u/tvavrda)
#### Post date: [September 19, 2025, 1:41pm UTC](https://meta.discourse.org/t/adding-an-invalid-tag-to-a-topic-creates-a-whisper-post/383286/1 "2025-09-19T13:41:59Z")
Reproduction steps:
1. Turn on this setting
[](https://global.discourse-cdn.com/meta/original/4X/f/2/5/f2591d4b4cd245fd144466f81e8caf0515a21f17.png "The image shows instructions for creating a post or a whisper post when a topic's category or tags change, requiring whisper posts to be enabled. (Captioned by AI)")
2. Limit a category to only a specific set of tags
3. Edit a subject of an existing topic in that category
4. Create a new tag by entering a new tag name into the tag area
5. Save the subject
Althought it seemed it was possible to add the tag, it won’t appear after saving (as it was not allowed). But when you look at the end of the topic, a whisper post was created that mentions the change of the tag.
Expected behavior: The whisper should not mention tags that were not created at all.
---
### Author:  [@sam](https://meta.discourse.org/u/sam)
#### Post date: [September 22, 2025, 12:21am UTC](https://meta.discourse.org/t/adding-an-invalid-tag-to-a-topic-creates-a-whisper-post/383286/2 "2025-09-22T00:21:01Z")
Interesting edge case, I wonder if we should put a #pr-welcome on this @hugh ?
---
### Author:  [@tvavrda](https://meta.discourse.org/u/tvavrda)
#### Post date: [September 22, 2025, 6:07am UTC](https://meta.discourse.org/t/adding-an-invalid-tag-to-a-topic-creates-a-whisper-post/383286/3 "2025-09-22T06:07:31Z")
Not sure if it is technically related but I also found another whisper related issue before.
> [@Changing a tag when "tracked" puts it to Unread for the current user](https://meta.discourse.org/t/changing-a-tag-when-tracked-puts-it-to-unread-for-the-current-user/349000):
>
> Repro steps: Turn on this setting Change a tag of a topic (add/remove) The whisper post is created as expected Go to the homepage Sometimes you need to refresh the brow…
---
### Author:  [@hugh](https://meta.discourse.org/u/hugh)
#### Post date: [September 30, 2025, 5:34am UTC](https://meta.discourse.org/t/adding-an-invalid-tag-to-a-topic-creates-a-whisper-post/383286/4 "2025-09-30T05:34:12Z")
Yeah, I added #pr-welcome to this. Thanks for reporting @tvavrda :slight_smile:
---
### Author:  [@TethysPlex](https://meta.discourse.org/u/TethysPlex)
#### Post date: [October 4, 2025, 1:48am UTC](https://meta.discourse.org/t/adding-an-invalid-tag-to-a-topic-creates-a-whisper-post/383286/5 "2025-10-04T01:48:53Z")
I’ve opened a PR on GitHub for this: [FIX: Ensure tag diffs use persisted topic tags by TethysPlex · Pull Request #35187 · discourse/discourse · GitHub](https://github.com/discourse/discourse/pull/35187)
---
### Author:  [@TethysPlex](https://meta.discourse.org/u/TethysPlex)
#### Post date: [December 4, 2025, 7:58am UTC](https://meta.discourse.org/t/adding-an-invalid-tag-to-a-topic-creates-a-whisper-post/383286/8 "2025-12-04T07:58:18Z")
bump.
could anyone review this?
---
### Author:  [@mcwumbly](https://meta.discourse.org/u/mcwumbly)
#### Post date: [December 4, 2025, 10:19am UTC](https://meta.discourse.org/t/adding-an-invalid-tag-to-a-topic-creates-a-whisper-post/383286/9 "2025-12-04T10:19:52Z")
I’ll see who might be available to take a look.
---
### Author:  [@zogstrip](https://meta.discourse.org/u/zogstrip)
#### Post date: [December 4, 2025, 3:58pm UTC](https://meta.discourse.org/t/adding-an-invalid-tag-to-a-topic-creates-a-whisper-post/383286/12 "2025-12-04T15:58:16Z")
Sorry for the delay @TethysPlex and thanks for the PR.
I have reviewed, made some light tweaks and merged it :+1:
---
### Author:  [@zogstrip](https://meta.discourse.org/u/zogstrip)
#### Post date: [December 5, 2025, 7:00am UTC](https://meta.discourse.org/t/adding-an-invalid-tag-to-a-topic-creates-a-whisper-post/383286/14 "2025-12-05T07:00:09Z")
This topic was automatically closed after 15 hours. New replies are no longer allowed.