What causes "${source}: branch name must not start or end with "/"." in abhigyanpatwari/GitNexus?

Strip leading/trailing slashes from the value before validation: `name.replace(/^\/+|\/+$/g, "")`.

abhigyanpatwari/GitNexus · error · InvalidBranchError

: branch name must not start or end with "/".

Error message

${source}: branch name must not start or end with "/".

What it means

validateBranchName rejects names that begin or end with '/', mirroring git check-ref-format. A leading or trailing slash can never appear in a ref git created, and a leading slash is used to reject input early so the failure is a clear validation error rather than a git subprocess failure.

Solutions

Strip leading/trailing slashes from the value before validation: `name.replace(/^\/+|\/+$/g, "")`.
Fix the string-building code — typically an empty variable or a duplicated '/' in a template literal.
Pass the short branch name ('feature/foo'), not a ref path with stray separators.

Example fix

// before
const branch = `${ns}/${name}`; // ns is "" -> "/feature"
validateBranchName(branch);
// after
const branch = [ns, name].filter(Boolean).join("/"); // "feature"
validateBranchName(branch);

Defensive patterns

Strategy: validation

Validate before calling

function hasEdgeSlashes(name) {
  return typeof name === "string" && (name.startsWith("/") || name.endsWith("/"));
}
branch = String(branch ?? "").replace(/^\/+|\/+$/g, "");

Type guard

function isTrimmedRef(v: unknown): v is string {
  return typeof v === "string" && v.length > 0 && !v.startsWith("/") && !v.endsWith("/");
}

Try / catch

try {
  validateBranchName(branch, "cli");
} catch (e) {
  if (e instanceof InvalidBranchError && e.message.includes('"/"')) {
    branch = branch.replace(/^\/+|\/+$/g, "");
    validateBranchName(branch, "cli");
  } else throw e;
}

Prevention

Always trim slashes from interpolated values before building a branch argument.
Use array filter(Boolean).join('/') for path-like joins so empty segments vanish.
Reject empty env/config variables early — they are the usual cause of leading slashes.
Pass short branch names, not ref paths, to branch parameters.

When it happens

Trigger: Calling validateBranchName with '/feature', 'feature/', or a value built by string concatenation like `/${env.BRANCH}` or `${branch}/`.

Common situations: Joining path segments with template strings (e.g. `` `${namespace}/${branch}` ``) where one side is empty; copying a full ref path 'refs/heads/main' variants; shell variable expansion producing empty prefix/suffix.

Understand the failure class

Background: "invalid id" errors: invalid identifier format — why libraries reject IDs before lookup, and how to fix them — this error's family across 37 libraries.

Related errors

AI-assisted analysis of abhigyanpatwari/GitNexus@ac9a4e9abd (2026-09-15). Data as JSON: /api/errors/3c212d0512963386. Report an issue: GitHub.

Appendix: source

Thrown at gitnexus/src/core/git-ref.ts:100

  }
  // The symbolic ref HEAD (case-sensitive). A repo can have a branch named
  // `head`; git itself treats only `HEAD` as the current-commit alias.
  if (trimmed === 'HEAD') {
    throw new InvalidBranchError(`${source}: branch name must not be "HEAD".`);
  }
  if (trimmed.includes('..')) {
    throw new InvalidBranchError(`${source}: branch name must not contain "..".`);
  }
  // The remaining `git check-ref-format` rules. Without these the validator
  // accepted refs git itself refuses (`feature.lock`, `/feature`, `feature/`,
  // `feature//next`, `@`, `.hidden`), so the failure surfaced later from the
  // git subprocess instead of here. No real branch can violate them — git
  // could not have created one — so nothing that works today starts failing.
  if (trimmed.endsWith('.lock') || trimmed.split('/').some((part) => part.endsWith('.lock'))) {
    throw new InvalidBranchError(`${source}: branch name must not end with ".lock".`);
  }
  if (trimmed.startsWith('/') || trimmed.endsWith('/')) {
    throw new InvalidBranchError(`${source}: branch name must not start or end with "/".`);
  }
  if (trimmed.includes('//')) {
    throw new InvalidBranchError(`${source}: branch name must not contain consecutive slashes.`);
  }
  if (trimmed === '@') {
    throw new InvalidBranchError(`${source}: branch name must not be the single character "@".`);
  }
  if (trimmed.includes('@{')) {
    throw new InvalidBranchError(`${source}: branch name must not contain "@{".`);
  }
  if (trimmed.endsWith('.') || trimmed.split('/').some((part) => part.startsWith('.'))) {
    throw new InvalidBranchError(
      `${source}: branch name must not end with "." or have a path component starting with ".".`,
    );
  }
  // Git permits a backtick in a ref, but the branch is embedded inside a
  // Markdown inline-code span in the generated AGENTS.md/CLAUDE.md regression
  // example, where a backtick would close the span early and let the rest of

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