Skip to content

Allow trailing dash in functional utility names #19696

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
RobinMalfait merged 3 commits into from
Feb 19, 2026
+47 −12
Merged

Allow trailing dash in functional utility names #19696

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
7b50a11
Allow trailing dash in functional utility names (e.g. `border--*`)
kirkouimet Feb 18, 2026
25f1789
update comment to talk about backwards compatibility
RobinMalfait Feb 19, 2026
f71d3c8
update changelog
RobinMalfait Feb 19, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 4 additions & 0 deletions CHANGELOG.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0

- _Experimental_: Add `@container-size` utility ([#18901](https://github.com/tailwindlabs/tailwindcss/pull/18901))

### Fixed

- Allow trailing dash in functional utility names for backwards compatibility ([#19696](https://github.com/tailwindlabs/tailwindcss/pull/19696))

## [4.2.0] - 2026-02-18

### Added
Expand Down
34 changes: 33 additions & 1 deletion packages/tailwindcss/src/utilities.test.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -28428,7 +28428,7 @@ describe('custom utilities', () => {
test.each([
['foo', false], // Simple name, missing '-*' suffix
['foo-*', true], // Simple name
['foo--*', false], // Root should not end in `-`
['foo--*', true], // Root ending in `-` is valid (e.g. `border--*`)
['-foo-*', true], // Simple name (negative)
['foo-bar-*', true], // With dashes
['foo_bar-*', true], // With underscores
Expand Down Expand Up @@ -28900,6 +28900,38 @@ describe('custom utilities', () => {
expect(await compileCss(input, ['tab-3', 'tab-gitlab'])).toEqual('')
})

test('functional utility with double-dash separator', async () => {
let input = css`
@theme reference {
--color-border-0: #e5e7eb;
--color-border-1: #d1d5db;
--color-border-2: #9ca3af;
}

@utility border--* {
border-color: --value(--color-border-*, [color]);
}

@tailwind utilities;
`

expect(await compileCss(input, ['border--0', 'border--1', 'border--2']))
.toMatchInlineSnapshot(`
".border--0 {
border-color: var(--color-border-0, #e5e7eb);
}

.border--1 {
border-color: var(--color-border-1, #d1d5db);
}

.border--2 {
border-color: var(--color-border-2, #9ca3af);
}"
`)
expect(await compileCss(input, ['border--3'])).toEqual('')
})

test('resolving values from `@theme`, with `--tab-size-*` syntax', async () => {
let input =
// Explicitly not using the css tagged template literal so that
Expand Down
21 changes: 10 additions & 11 deletions packages/tailwindcss/src/utilities.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -6659,22 +6659,21 @@ export function isValidFunctionalUtilityName(name: string): boolean {
let root = match[0]
let value = name.slice(root.length)

// Root should not end in `-` if there is no value
//
// `tab-size--*`
// --------- Root
// -- Suffix
//
// Because with default values, this could match `tab-size-` which is invalid.
if (value.length === 0 && root.endsWith('-')) {
return false
}

// No remaining value is valid
//
// `tab-size-*`
// -------- Root
// -- Suffix
//
// Backwards compatibility: a root ending in `-` was valid and correctly
// scanned by Oxide. This means that custom utilities can result in candidates
// such as `foo--bar`.
//
// We might want to revisit this for Tailwind CSS v5, but for now we have to
// make it backwards compatible.
//
// PR: https://github.com/tailwindlabs/tailwindcss/pull/19696
//
if (value.length === 0) {
return true
}
Expand Down