ruby/rubygems · error · Gem::SafeMarshal::Visitors::ToRuby::FormatError

Unexpected value for String :E #{v.inspect}

Error message

Unexpected value for String :E #{v.inspect}

What it means

Error "Unexpected value for String :E #{v.inspect}" thrown in ruby/rubygems.

Source

Thrown at lib/rubygems/safe_marshal/visitors/to_ruby.rb:135

              dumped[0, 2] = ""
              marshal_string.concat(dumped)
            end

            object = @objects[object_offset] = Marshal.load(marshal_string)
          end
        when Elements::String
          enc = nil

          ivars.reject! do |k, v|
            case k
            when :E
              case v
              when TrueClass
                enc = "UTF-8"
              when FalseClass
                enc = "US-ASCII"
              else
                raise FormatError, "Unexpected value for String :E #{v.inspect}"
              end
            when :encoding
              enc = v
            else
              next false
            end
            true
          end

          object.force_encoding(enc) if enc
        end

        ivars.each do |k, v|
          object.instance_variable_set k, v
        end
        object
      end

View on GitHub (pinned to 86cbb817a3)

Solutions

1. The metadata string encoding flag is invalid; the file is corrupt — re-download the gem

When it happens

Trigger: Thrown at lib/rubygems/safe_marshal/visitors/to_ruby.rb:135 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of ruby/rubygems@86cbb817a3 (2026-08-23). Data as JSON: /api/errors/55eb33bad87edb98. Report an issue: GitHub.