refined-github/refined-github · error · Error

Invalid compare URL format

Error message

Invalid compare URL format

What it means

parseCompareUrl splits the head segment of a compare URL (owner:repo:branch) and throws when, after extracting branch, owner, and repo, leftover parts remain — meaning the URL has an impossible number of colon-separated segments.

Source

Thrown at source/github-helpers/parse-compare-url.ts:33

};

const compareRegex = /compare[/](?<baseBranch>[^.]+)[.][.][.]?(?<heads>.+)/;
export default function parseCompareUrl(pathname: string): Comparison | undefined {
	const base = getRepo(pathname)!;

	const match = compareRegex.exec(base.path);
	if (match === null) {
		return;
	}

	const {baseBranch, heads} = match.groups!;
	const headParts = heads.split(':');
	const headBranch = headParts.pop()!; // Branch is always last, or the only one
	const headOwner = headParts.shift() ?? base.owner; // The owner is first, or it's the same as the base
	const headName = headParts.pop() ?? base.name; // The repo is first or middle, or it's the same as the base

	if (headParts.length > 0) {
		throw new Error('Invalid compare URL format');
	}

	const headRepo: NameWithOwner = `${headOwner}/${headName}`;

	return {
		base: {
			repo: base.nameWithOwner,
			branch: baseBranch,
		},
		head: {
			repo: headRepo,
			branch: headBranch,
		},
		isCrossRepo: headRepo !== base.nameWithOwner,
	};
}

View on GitHub (pinned to 73afd11264)

Solutions

1. Validate the compare URL shape before parsing (head must have 1-3 colon-separated parts)
2. URL-encode or strip illegal colons from branch names
3. Handle the throw and fall back to treating the whole head as a branch name

Example fix

// before
const {base, head} = parseCompareUrl(location.pathname);

// after
const head = location.pathname.split('...')[1] ?? '';
if (head.split(':').length > 3) continue; // skip malformed compare URLs
const parsed = parseCompareUrl(location.pathname);

const head = url.split('...')[1] ?? '';
const parts = head.split(':');
const isValid = parts.length >= 1 && parts.length <= 3;
if (!isValid) return null;

const isParseableCompareHead = (head: string): boolean => head.split(':').length <= 3;

try {
	const parsed = parseCompareUrl(pathname);
} catch (error) {
	if (error instanceof Error && error.message === 'Invalid compare URL format') return;
	throw error;
}

When it happens

Trigger: A compare URL whose head part contains more than 3 segments, e.g. /compare/base...a:b:c:d, or unexpected colons in branch names combined with explicit owner/repo. Well-formed heads are 'branch', 'owner:branch', or 'owner:repo:branch'.

Common situations: Branch names containing colons (rare/illegal in Git but possible in mangled URLs), user-pasted or programmatically constructed compare URLs with extra separators, URL encoding bugs producing stray colons.

Related errors

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AI-assisted analysis of refined-github/refined-github@73afd11264 (2026-08-27). Data as JSON: /api/errors/cea59aa9b2c3b4c4. Report an issue: GitHub.