fix: preserve `#` in branch names during frontend slugification by themavik · Pull Request #12322 · gitbutlerapp/gitbutler

themavik · 2026-02-11T15:23:51Z

Summary

Branch names containing # (e.g. feat/#1234-ticket-name) have the # silently stripped when creating or renaming branches. This is because the frontend's slugify function uses a character allowlist that doesn't include #, even though # is a valid character in git ref names.

The backend's normalize_short_name correctly preserves # (confirmed by existing Rust tests: foo#branch → foo#branch). The issue is purely in the frontend BranchNameTextbox component.

Root Cause

packages/ui/src/lib/utils/string.ts:

// This regex strips # because it's not in the allowed set
.replace(/[^A-Za-z0-9._/ -]/g, '')

This slugify is also used for non-branch contexts (org slugs, markdown headings) where # should be stripped, so modifying it directly would break those contexts.

Fix

New function slugifyBranchName in packages/ui/src/lib/utils/string.ts — a branch-name-aware variant that additionally allows # and @ (both valid in git refs)
BranchNameTextbox.svelte now imports slugifyBranchName instead of the generic slugify
The generic slugify remains unchanged for non-branch contexts (OrganizationEditModal, Heading.svelte)

Changes

packages/ui/src/lib/utils/string.ts — Add slugifyBranchName function
packages/ui/src/lib/utils/string.test.ts — Add 7 tests for the new function
apps/desktop/src/components/BranchNameTextbox.svelte — Use slugifyBranchName

Test Plan

New vitest tests cover #, @, slashes, periods, whitespace, git-invalid chars
Existing slugify tests unmodified and still pass
Backend already preserves # (Rust test: normalize_short_name("foo#branch") == "foo#branch")
Manual: type feat/#1234-ticket in branch name input → should show the # preserved

The generic `slugify` function strips all characters outside `A-Za-z0-9._/ -`, which removes `#` from branch names like `feat/#1234-ticket-name`. However, `#` is a valid character in git ref names (confirmed by the backend's `normalize_short_name` tests). Introduce `slugifyBranchName` — a branch-name-aware variant that additionally allows `#` and `@` (both valid in git refs). Update `BranchNameTextbox.svelte` to use this instead of the generic `slugify`, which remains unchanged for non-branch contexts (e.g., organization slugs, markdown heading IDs). Closes #9076

vercel · 2026-02-11T15:23:59Z

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Byron

Thanks a lot for fixing this!

The problem is indeed resolved.

Screen.Recording.2026-02-16.at.09.56.09.mov

What I wonder though is if the frontend shouldn't just use the backend function instead of implementing its own?

Could @estib-vega decide if this can be merged, and if it makes sense to have a follow-up that relies completely on the backend instead?

Copilot

Pull request overview

This pull request fixes issue #9076 where the # character is silently stripped from branch names during creation or renaming in the frontend. The root cause is that the generic slugify function uses a character allowlist that doesn't include #, even though it's valid in git ref names. The fix introduces a new slugifyBranchName function specifically for branch names that preserves git-valid characters like # and @.

Changes:

Added slugifyBranchName function to preserve git-valid characters in branch names
Updated BranchNameTextbox component to use the new branch-aware slugification
Added comprehensive tests for the new function

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
packages/ui/src/lib/utils/string.ts	Adds new `slugifyBranchName` function with expanded character allowlist including `#` and `@`
packages/ui/src/lib/utils/string.test.ts	Adds 7 tests covering the new function's behavior with git-valid and git-invalid characters
apps/desktop/src/components/BranchNameTextbox.svelte	Updates import and usage to use `slugifyBranchName` instead of generic `slugify`

Copilot · 2026-02-16T09:05:23Z

packages/ui/src/lib/utils/string.ts

+		.normalize('NFKD')
+		.replace(/[\u0300-\u036f]/g, '')
+		.trim()
+		.replace(/[^A-Za-z0-9._/#@ -]/g, '')


The character allowlist is more restrictive than the backend's normalize_short_name function. The backend preserves characters like +, <, >, and ! (see crates/but-core/tests/core/branch/normalize_short_name.rs lines 7, 11-12, 53), but this regex strips them. This creates inconsistency where users could type feature+bugfix in the UI, see it stripped to featurebugfix, but the backend would accept feature+bugfix as valid. Consider adding +<>! to the allowlist to match backend behavior.

Suggested change

.replace(/[^A-Za-z0-9._/#@ -]/g, '')

.replace(/[^A-Za-z0-9._/#@+<>! -]/g, '')

Copilot · 2026-02-16T09:05:24Z

packages/ui/src/lib/utils/string.ts

+export function slugifyBranchName(input: string) {
+	return String(input)
+		.normalize('NFKD')
+		.replace(/[\u0300-\u036f]/g, '')
+		.trim()
+		.replace(/[^A-Za-z0-9._/#@ -]/g, '')
+		.replace(/\s+/g, '-')
+		.replace(/-+/g, '-');
+}


The backend's normalize_short_name strips -, ., and / from the beginning and end of branch names (see crates/but-core/src/branch/normalize.rs lines 9-25). The frontend doesn't implement this logic, which could lead to inconsistency. For example, -my-branch- would show as-is in the UI but be saved as my-branch by the backend. Consider adding similar logic to strip these characters from the start and end to match backend behavior and provide accurate preview to users.

Copilot · 2026-02-16T09:05:24Z

packages/ui/src/lib/utils/string.ts

+		.normalize('NFKD')
+		.replace(/[\u0300-\u036f]/g, '')
+		.trim()
+		.replace(/[^A-Za-z0-9._/#@ -]/g, '')


The @ character is included in the allowlist, but there are no backend tests confirming that @ is preserved by normalize_short_name (see crates/but-core/tests/core/branch/normalize_short_name.rs). The @ character has special meaning in git refs (e.g., HEAD@{1}), so it's worth verifying that @ is actually safe to allow in branch names. Consider adding a backend test to confirm this behavior or removing @ from the allowlist if it's not supported.

Suggested change

.replace(/[^A-Za-z0-9._/#@ -]/g, '')

.replace(/[^A-Za-z0-9._/# -]/g, '')

Copilot · 2026-02-16T09:05:24Z

packages/ui/src/lib/utils/string.test.ts

+	test('at sign is preserved', () => {
+		expect(slugifyBranchName('user@feature')).toEqual('user@feature');
+	});
+


This test assumes @ is valid in git branch names, but there's no corresponding backend test confirming that normalize_short_name preserves @. The @ character has special meaning in git refs (e.g., HEAD@{1}), so verify this is actually supported by the backend before including it in tests. Consider adding a backend test first, or remove this test if @ is not supported.

Suggested change

test('at sign is preserved', () => {

expect(slugifyBranchName('user@feature')).toEqual('user@feature');

});

Byron · 2026-02-18T15:18:56Z

Maybe @mtsgrd could take a look then?

Byron · 2026-02-22T12:55:59Z

Superseded by #12488 .

Byron approved these changes Feb 16, 2026

View reviewed changes

Byron added the 🎉reproduced🎉 The issue could be reproduced by following the instructions label Feb 16, 2026

Byron requested a review from Copilot February 16, 2026 08:58

Copilot started reviewing on behalf of Byron February 16, 2026 08:59 View session

Copilot AI reviewed Feb 16, 2026

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Byron requested a review from estib-vega February 16, 2026 09:12

Byron requested a review from mtsgrd February 18, 2026 15:19

nshcr mentioned this pull request Feb 22, 2026

feat(ui): use backend normalize method to validate user-entered branch names #12488

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Byron closed this Feb 22, 2026

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fix: preserve `#` in branch names during frontend slugification#12322

fix: preserve `#` in branch names during frontend slugification#12322
themavik wants to merge 1 commit intogitbutlerapp:masterfrom
themavik:fix/branch-name-hashtag

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	.replace(/[^A-Za-z0-9._/#@ -]/g, '')
	.replace(/[^A-Za-z0-9._/#@+<>! -]/g, '')

	.replace(/[^A-Za-z0-9._/#@ -]/g, '')
	.replace(/[^A-Za-z0-9._/# -]/g, '')

	test('at sign is preserved', () => {
	expect(slugifyBranchName('user@feature')).toEqual('user@feature');
	});

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themavik commented Feb 11, 2026

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Root Cause

Fix

Changes

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