Mysterious "Tags is invalid" message

We have an “Open Source” plan site hosted on Recently, a “Tags is invalid” message has been a problem for our users who are trying to post. I cannot quite figure out why this keeps happening, and how to solve it. I am looking for advice with this.

I fear that several new forum members may have been put off from posting by this, and we may never even have noticed. Considering that our forum is still quite new, this is a serious problem.

Our setup:

We have a “Usage” category. The intent is to require all posts in this category to have at least one tag from the language tag group. It may also have other tags, but at least one tag from the language group must always be present. This is because this is a support forum for a software library that has (rather divergent) bindings to several programming languages. Users often forget to mention which binding they are using. Their questions cannot be answered without knowing this.

Here’s the configuration for the “Usage” category:

The language tag group:

Illustration of the problem:

This is what happens if I try to create a new post. Strangely, if I then remove all tags, the post will go through (even though one tag should be required).

Sample post:

Error message:

1 Like

:warning:: wild guess
Would it be possible that the “c” tag somehow conflicts with the “c” route for category?



I have same symptoms but you can edit tags with title editing which is works great to me.

1 Like

I can not reproduce it at this moment, and I have not idea why. Yet this problem has been occurring for a number of weeks before I asked about it here. I am very confused.

Can someone from Discourse comment please?

1 Like

I don’t understand what you mean by “you can edit tags with title editing”. Can you clarify?

Sorry my mistake I have the same issue when editing topic tags and not when create new one.

I mean when you edit title then you can add or remove tags and that’s works for me.

1 Like

well, close enough :sweat_smile:

It might/should work after a rebuild :crossed_fingers:


I’m just surprised that it was even allowed to create the tag!


with 2.6.0.beta1 ( b9174c8e8a ), before the fix, I wasn’t able to create it (without any error message though, clicking on save on a tag group with “c” just doesn’t save the group, after a page refresh, “c” tag doesn’t appear).

You might try to repro the problem with “none” tag ?

1 Like

Do you know when this fix will come to sites? I never paid much attention to releases as everything was conveniently managed and updated by Discourse themselves. :slight_smile:

1 Like

Ah yes I overlooked that part :thinking: I don’t know about the update for hosted sites but in the mean time you can use “language C” or anything else and correct it to “C” as soon as the fix is deployed, https://your.domain/tag/your-tag click on “details” then “rename”
and may I add, for tipping my hat to the new gif component:


1 Like

Your are probably right, maybe t̶h̶e̶ ̶T̶a̶g̶G̶r̶o̶u̶p̶ ̶c̶l̶a̶s̶s̶ ̶i̶n̶ ̶h̶t̶t̶p̶s̶:̶/̶/̶g̶i̶t̶h̶u̶b̶.̶c̶o̶m̶/̶d̶i̶s̶c̶o̶u̶r̶s̶e̶/̶d̶i̶s̶c̶o̶u̶r̶s̶e̶/̶b̶l̶o̶b̶/̶m̶a̶s̶t̶e̶r̶/̶a̶p̶p̶/̶m̶o̶d̶e̶l̶s̶/̶t̶a̶g̶_̶g̶r̶o̶u̶p̶.̶r̶b something could beneficiate of the validate :name_validator of the Tag class, but i don’t know… way above my paygrade :sweat_smile:

1 Like