windmill-labs/windmill · error · Error

Refusing to rename your current branch \`${currentBranch}\`

Error message

Refusing to rename your current branch \`${currentBranch}\` — it looks like a base branch (mapped to a workspace in wmill.yaml, or main/master). Check out the disposable working branch you want to convert first.

What it means

With `--from-branch`, the CLI renames the current branch into the fork branch (git branch -m). Renaming a 'base branch' — one mapped to a workspace in wmill.yaml or the conventional main/master — would rebind the workspace-to-branch mapping and break the git sync workflow. The guard `isBaseBranch(currentBranch)` throws before any rename happens.

Source

Thrown at cli/src/commands/workspace/fork.ts:70

    branch === "master" ||
    findWorkspaceByGitBranch(config.workspaces, branch) !== undefined;

  // Decide the base branch the fork links to, and whether to rename the
  // current working branch onto the fork branch. Auto-detected from where you
  // are; `--from-branch` is the explicit/non-interactive override.
  let clonedBranchName: string;
  let renameCurrent: boolean;

  if (opts.fromBranch) {
    // Explicit override: base on <fromBranch>, rename the current branch.
    if (opts.fromBranch === currentBranch) {
      throw new Error(
        `--from-branch is for converting a *different* working branch into the fork branch, but you are already on \`${currentBranch}\`. ` +
        `Omit --from-branch to create a fresh fork branch with \`git checkout -b\`.`,
      );
    }
    if (isBaseBranch(currentBranch)) {
      throw new Error(
        `Refusing to rename your current branch \`${currentBranch}\` — it looks like a base branch (mapped to a workspace in wmill.yaml, or main/master). ` +
        `Check out the disposable working branch you want to convert first.`,
      );
    }
    if (getOriginalBranchForWorkspaceForks(currentBranch)) {
      // Current branch is itself a fork branch (wm-fork/<base>/<old-id>).
      // Renaming it onto the new fork branch would detach the existing fork.
      throw new Error(
        `Refusing to rename your current branch \`${currentBranch}\` — it is already a fork branch. ` +
        `To fork a fork, omit --from-branch: \`wmill workspace fork\` bases the new fork on this fork's original branch and creates a fresh fork branch without renaming.`,
      );
    }
    if (!findWorkspaceByGitBranch(config.workspaces, opts.fromBranch)) {
      throw new Error(
        `Could not find a workspace mapped to branch \`${opts.fromBranch}\` in wmill.yaml's workspaces section. ` +
        `Pass the base branch your fork should be based on (e.g. the branch bound to the parent workspace).`,
      );
    }

View on GitHub (pinned to e474e8803c)

Solutions

  1. Check out the disposable working branch you want to convert first: `git switch <working-branch>`, then run the fork command with --from-branch
  2. If you want a fresh fork branch instead, omit --from-branch (allowed from a base branch) and the CLI will `git checkout -b` a new fork branch
  3. Rename or unmap the branch in wmill.yaml only if you truly intend to rebind the base workspace

Example fix

// before
git switch main
wmill workspace fork --from-branch develop  # refusal
// after
git switch my-experimental-branch
wmill workspace fork --from-branch develop
Defensive patterns

Strategy: validation

Validate before calling

const current = execSync('git branch --show-current', { encoding: 'utf8' }).trim();
const isBase = current === 'main' || current === 'master' || config.workspaces.some(w => w.gitBranch === current);
if (opts.fromBranch && isBase) {
  throw new Error(`Check out a disposable working branch before using --from-branch (on ${current}).`);
}
await createWorkspaceFork(opts, name);

Type guard

function isBaseBranch(branch: string, workspaces: { gitBranch?: string }[]): boolean {
  return branch === 'main' || branch === 'master' || workspaces.some(w => w.gitBranch === branch);
}

Try / catch

try {
  await createWorkspaceFork(opts, name);
} catch (e) {
  if ((e as Error).message.includes('looks like a base branch')) {
    console.error('git switch to your working branch first, then retry with --from-branch.');
  } else throw e;
}

Prevention

When it happens

Trigger: Running `wmill workspace fork --from-branch <other>` while the current branch is `main`, `master`, or a branch mapped to a workspace in wmill.yaml's workspaces section.

Common situations: Trying to fork while still sitting on main instead of a feature branch; wmill.yaml maps several branches to workspaces and the user forgot which one they are on; habit of running fork from the default checkout branch.

Related errors

AI-assisted analysis of windmill-labs/windmill@e474e8803c (2026-09-03). Data as JSON: /api/errors/f258bee0c6860f8e. Report an issue: GitHub.