phacility/phabricator · error · Exception

Expected `%s`!

Error message

Expected `%s`!

What it means

The Mercurial SSH workflow expects clients to invoke exactly 'hg -R <path> serve --stdio', the standard hg SSH wire command. After parsing the SSH-side arguments (-R/--repository, --stdio, and a wildcard command), a missing --stdio flag throws this exception.

Source

Thrown at src/applications/diffusion/ssh/DiffusionMercurialServeSSHWorkflow.php:40

          'wildcard' => true,
        ),
      ));
  }

  protected function identifyRepository() {
    $args = $this->getArgs();
    $path = $args->getArg('repository');
    return $this->loadRepositoryWithPath(
      $path,
      PhabricatorRepositoryType::REPOSITORY_TYPE_MERCURIAL);
  }

  protected function executeRepositoryOperations() {
    $repository = $this->getRepository();
    $args = $this->getArgs();

    if (!$args->getArg('stdio')) {
      throw new Exception(pht('Expected `%s`!', 'hg ... --stdio'));
    }

    if ($args->getArg('command') !== array('serve')) {
      throw new Exception(pht('Expected `%s`!', 'hg ... serve'));
    }

    if ($this->shouldProxy()) {
      // NOTE: For now, we're always requesting a writable node. The request
      // may not actually need one, but we can't currently determine whether
      // it is read-only or not at this phase of evaluation.
      $command = $this->getProxyCommand(true);
    } else {
      $command = csprintf(
        'hg -R %s serve --stdio',
        $repository->getLocalPath());
    }
    $command = PhabricatorDaemon::sudoCommandAsDaemonUser($command);

View on GitHub (pinned to 5720a38cfe)

Solutions

1. Let hg build the command itself: hg clone ssh://user@host/source/<shortname>
2. Upgrade the Mercurial client to a supported version
3. Do not run arbitrary hg subcommands through the Phabricator SSH endpoint — only serve --stdio is implemented

// Client side: let hg construct the wire command itself
// good: hg clone ssh://user@host/source/<shortname>
// bad:  ssh user@host hg -R /diffusion/X/ serve   (no --stdio)

When it happens

Trigger: Hand-running a custom command over the Phabricator SSH endpoint (ssh user@host hg -R /diffusion/X/ serve without --stdio), or a nonstandard or very old Mercurial client that omits the flag.

Common situations: Manual ssh debugging sessions; exotic hg wrappers or CI tooling invoking hg directly; hg versions below the supported baseline.

Related errors

• Unknown Mercurial command "%s"!
• This repository ("%s") is not a Mercurial repository. Use "%
• This repository ("%s") is not available over SSH.
• Configuration file specifies cluster peer ("%s", at index "%
• This public key is already associated with another user or d

AI-assisted analysis of phacility/phabricator@5720a38cfe (2026-08-21). Data as JSON: /api/errors/e0a29383bd497f61. Report an issue: GitHub.