After selecting 'No Label' for any category, switching categories triggers an error: 'Oops! This page does not exist or is not public.'

zogstrip · May 11, 2026, 6:51pm

Thanks for the report @哈基米曼波 This should fix the issue

github.com/discourse/discourse

FIX: 404 when switching categories with the "No tags" filter active (#39894)

main ← fix-category-switch-with-no-tags-filter

merged 07:32PM - 12 May 26 UTC

ZogStriP

+33 -42

When a user opened a category, selected "No tags" in the tag dropdown, and then …picked another category from the breadcrumb, they landed on a 404 page instead of the new category with the "No tags" filter preserved. The breadcrumb's `CategoryDrop` passes its `tag` argument straight to `getCategoryAndTagUrl`. On a `/tags/c/<slug>/<id>/none` page that `tag` is a `Tag` model with `slug: "none"` and `id: null` — not the literal string `"none"` that `TagDrop` passes from its own handler. The URL builder unconditionally appended `tag.slug + "/" + tag.id`, producing `/tags/c/<new-slug>/<new-id>/none/null`, which no route can resolve. This normalizes the tag handling in `getCategoryAndTagUrl` so that any tag without an `id` (the "no tags" filter, whether expressed as a string or as a Tag model) renders as `.../<slug>` instead of `.../<slug>/null`. The category branch is also tidied up — it had an unreachable inner `else` because the outer condition already required `subcategories` to be true. https://meta.discourse.org/t/402545

Topic		Replies	Views
/tags/none route doesn't exist Bug	5	807	November 16, 2020
Inconsistency tags/tags ->category UX	0	503	December 4, 2020
Clicking on a category from a tags page leads to undefined page Bug	3	945	November 6, 2015
Routing problems with Discourse tagging plugin Bug	10	2451	May 9, 2017
Missing routes for tags.showCategory and tags.showParentCategory Bug	4	1458	May 6, 2016

After selecting 'No Label' for any category, switching categories triggers an error: 'Oops! This page does not exist or is not public.'

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