Inconsistent permission to use the same tag in the same category

zogstrip · April 15, 2026, 8:31pm

Ahah, my bad The feature needed to be a tad bit “smarter” when it comes to limits

github.com/discourse/discourse

FIX: don't mislabel allowed tags as disabled in composer tag search (#39300)

main ← fix-disabled-tags-mislabeled

merged 07:01AM - 16 Apr 26 UTC

ZogStriP

+54 -6

When searching tags in the composer, `filter_allowed_tags` applies a LIMIT (`max…_tag_search_results`, default 5). If more allowed tags match the query than fit under the limit, the overflow is silently dropped. `append_disabled_tags` then ran a naive substring query for visible tags matching the term, assumed any tag not in the allowed list must be excluded by filter rules, and asked `explain_exclusion` to fabricate a reason. Allowed-but-cut-off tags leaked into the disabled list and showed the vague fallback "\"X\" cannot be used in this category". Because `filter_allowed_tags` orders by term (`DISTINCT ON (lower(name) = lower(term), ...)`), the same tag could appear allowed under one search term (prefix match, ranks high, fits in the limit) and disabled under another (mid-string match, ranks lower, gets cut off) — producing inconsistent verdicts for the same tag in the same category. Before labeling any tag as disabled or forbidden, re-run `filter_allowed_tags` scoped to the candidate names (no limit) and drop any that come back allowed. Extracted to `reject_allowed_tags` so both `append_disabled_tags` and `detect_forbidden_tag` go through the same verification. The probe is skipped when the allowed result didn't saturate its limit, since no cutoff is possible in that case. https://meta.discourse.org/t/400696

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Inconsistent permission to use the same tag in the same category

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