windmill-labs/windmill · error · Error

--from-branch is for converting a *different* working branch

Error message

--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\`.

What it means

`--from-branch` explicitly means 'rename my current disposable working branch onto the new fork branch, basing it on <from-branch>'. Passing the branch you are currently standing on as `--from-branch` is contradictory: there is nothing different to convert. The CLI detects `opts.fromBranch === currentBranch` and throws before touching anything.

Source

Thrown at cli/src/commands/workspace/fork.ts:64

  const originalBranchIfForked = getOriginalBranchForWorkspaceForks(currentBranch);

  // A "base branch" is one we must not rename onto a fork branch: mapped to a
  // workspace in wmill.yaml, or a conventional default (main/master).
  const isBaseBranch = (branch: string): boolean =>
    branch === "main" ||
    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.`,
      );
    }

View on GitHub (pinned to e474e8803c)

Solutions

1. Omit `--from-branch` if you want a fresh fork branch created via git checkout -b
2. If you really want to convert the current branch, just run `wmill workspace fork` without the flag while on a non-base working branch
3. Pass a different branch (the base branch mapped to the parent workspace) as --from-branch

Example fix

// before
git switch feature-x
wmill workspace fork --from-branch feature-x  # error
// after
wmill workspace fork  # omit --from-branch; converts feature-x into the fork branch

const current = execSync('git branch --show-current', { encoding: 'utf8' }).trim();
if (opts.fromBranch && opts.fromBranch === current) {
  throw new Error(`Omit --from-branch: you are already on ${current}.`);
}
await createWorkspaceFork(opts, name);

null

try {
  await createWorkspaceFork(opts, name);
} catch (e) {
  if ((e as Error).message.includes('is for converting a *different* working branch')) {
    console.error('Drop --from-branch or check out a different branch first.');
  } else throw e;
}

When it happens

Trigger: Running `wmill workspace fork --from-branch <X>` while HEAD is already on branch X.

Common situations: Copy-pasting a command template that hardcodes the branch name; confusing --from-branch with the base branch you are already on; scripting the command with `$(git branch --show-current)` as the flag value.

Understand the failure class

Background: "Unknown argument", "Invalid value", and "must be one of": invalid CLI argument errors explained — this error's family across 35 libraries.

Related errors

• file path must refer to a file.
• file path must refer to a file.
• You can only create forks within a git repo. Forks are track
• Could not get git branch name
• Refusing to rename your current branch \`${currentBranch}\`

AI-assisted analysis of windmill-labs/windmill@e474e8803c (2026-09-03). Data as JSON: /api/errors/ccb1334879150f1e. Report an issue: GitHub.