abhigyanpatwari/GitNexus · error · InvalidBranchError

: branch name must not contain consecutive slashes.

Error message

${source}: branch name must not contain consecutive slashes.

What it means

validateBranchName rejects names containing '//' (consecutive slashes), matching git's ref-format rules; git itself never creates refs with empty path components. The library throws a descriptive InvalidBranchError early rather than letting the git subprocess fail later with a less clear message.

Solutions

  1. Collapse consecutive slashes: `name.replace(/\/{2,}/g, "/")` before validating.
  2. Fix the join logic so empty segments are filtered out (e.g. `[a, b].filter(Boolean).join("/")`).
  3. Verify the source variable (env var, config key) is actually populated.

Example fix

// before
const branch = `${group}/${sub}/${name}`; // group empty -> "//feature"
validateBranchName(branch);
// after
const branch = [group, sub, name].filter(Boolean).join("/");
validateBranchName(branch);
Defensive patterns

Strategy: validation

Validate before calling

function hasDoubleSlash(name) { return typeof name === "string" && name.includes("//"); }
branch = String(branch ?? "").replace(/\/{2,}/g, "/");

Type guard

function isSingleSlashed(v: unknown): v is string {
  return typeof v === "string" && !v.includes("//");
}

Try / catch

try {
  validateBranchName(branch, "http");
} catch (e) {
  if (e instanceof InvalidBranchError && e.message.includes("consecutive slashes")) {
    return res.status(400).json({ error: "branch names must not contain '//'" });
  }
  throw e;
}

Prevention

When it happens

Trigger: Calling validateBranchName with 'feature//next' or names built by joining segments where an empty segment occurs, e.g. `${a}/${b}` with empty a or b, or double slashes from copy-pasted URLs/paths.

Common situations: CI environment variables that are empty or unset producing 'origin//branch'; naive path joins; pasting 'refs/heads//name' style strings.

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/7e912facf0b5c34d. Report an issue: GitHub.

Appendix: source

Thrown at gitnexus/src/core/git-ref.ts:103

  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
  // the template render as instruction text. Reject it at this single
  // chokepoint so all three tiers (CLI flag, .gitnexusrc, auto-detect via
  // sanitizeDetectedBranch) are covered (#1996 tri-review P1).

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