emberjs/ember.js · error · Error

Unexpected missing # in block head

Error message

Unexpected missing # in block head

What it means

Error "Unexpected missing # in block head" thrown in emberjs/ember.js.

Source

Thrown at packages/@glimmer/compiler/lib/builder/builder-interface.ts:330

        hash: normalizeHash(statement[2]),
        block: normalizeBlock(statement[3]),
      };
    }

    case BUILDER_COMMENT: {
      return {
        kind: COMMENT_HEAD,
        value: statement[1],
      };
    }
  }
}

function extractBlockHead(name: string): NormalizedHead {
  const result = /^(#|!)(.*)$/u.exec(name);

  if (result === null) {
    throw new Error(`Unexpected missing # in block head`);
  }

  return normalizeDottedPath(result[2] as string);
}

function normalizeCallHead(name: string): NormalizedHead {
  const result = /^\((.*)\)$/u.exec(name);

  if (result === null) {
    throw new Error(`Unexpected missing () in call head`);
  }

  return normalizeDottedPath(result[1] as string);
}

function normalizePath(head: string, tail: string[] = []): NormalizedHead {
  const pathHead = normalizePathHead(head);

View on GitHub (pinned to 26f97246a8)

When it happens

Trigger: Thrown at packages/@glimmer/compiler/lib/builder/builder-interface.ts:330 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of emberjs/ember.js@26f97246a8 (2026-09-01). Data as JSON: /api/errors/41fdc8ef34de0956. Report an issue: GitHub.