class RSpec::Support::EncodedString

@private

def self.pick_encoding(source_a, source_b) 

def self.pick_encoding(source_a, source_b)
  Encoding.compatible?(source_a, source_b) || Encoding.default_external
end

def self.pick_encoding(_source_a, _source_b) 

def self.pick_encoding(_source_a, _source_b)
end

def <<(string) 

def <<(string)
  @string << matching_encoding(string)
end

def detect_source_encoding(string) 

def detect_source_encoding(string)
  string.encoding
end

def detect_source_encoding(_string) 

def detect_source_encoding(_string)
  US_ASCII
end

def initialize(string, encoding=nil) 

def initialize(string, encoding=nil)
  @encoding = encoding
  @source_encoding = detect_source_encoding(string)
  @string = matching_encoding(string)
end

def matching_encoding(string)

e.g. the UTF-16LE emoji: 128169.chr
RangeError: out of char range
Raised by byte <-> char conversions

e.g. "\x80".force_encoding('ASCII-8BIT').encode('Emacs-Mule')
or a converter path cannot be found
e.g. 'abc'.force_encoding('UTF-8').encode('foo')
when a named encoding does not correspond with a known converter
Encoding::ConverterNotFoundError:
Raised by transcoding methods:

that doesn't respond to #to_str
when calling force_encoding on an object
Encoding.find(:"UTF-8")
when a symbol is passed as an encoding
TypeError
e.g."\x80".split("\n")
when operating on a string with invalid bytes
ArgumentError
# => ''
vs "\x80".encode('UTF-8','US-ASCII', invalid: :replace, replace: '')
e.g. "\x80".encode('UTF-8','US-ASCII')
either the source or target encoding
when the string being transcoded contains a byte invalid for
Encoding::InvalidByteSequenceError:
e.g. valid_unicode_string.encode(utf8_encoding) << ascii_string
e.g. utf_16le_emoji_string.split("\n")
when Encoding.compatible?(str1, str2) is nil
Encoding::CompatibilityError
# => ''
vs "\x80".encode('UTF-8','ASCII-8BIT', undef: :replace, replace: '')
e.g. "\x80".encode('UTF-8','ASCII-8BIT')
if the String contains characters invalid for the target encoding
when a transcoding operation fails
Encoding::UndefinedConversionError:
Raised by Encoding and String methods:

Encoding Exceptions: 
def matching_encoding(string)
  string = remove_invalid_bytes(string)
  string.encode(@encoding)
rescue Encoding::UndefinedConversionError, Encoding::InvalidByteSequenceError
  # Originally defined as a constant to avoid unneeded allocations, this hash must
  # be defined inline (without {}) to avoid warnings on Ruby 2.7
  #
  # In MRI 2.1 'invalid: :replace' changed to also replace an invalid byte sequence
  # see https://github.com/ruby/ruby/blob/v2_1_0/NEWS#L176
  # https://www.ruby-forum.com/topic/6861247
  # https://twitter.com/nalsh/status/553413844685438976
  #
  # For example, given:
  #   "\x80".force_encoding("Emacs-Mule").encode(:invalid => :replace).bytes.to_a
  #
  # On MRI 2.1 or above: 63  # '?'
  # else               : 128 # "\x80"
  #
  string.encode(@encoding, :invalid => :replace, :undef => :replace, :replace => REPLACE)
rescue Encoding::ConverterNotFoundError
  # Originally defined as a constant to avoid unneeded allocations, this hash must
  # be defined inline (without {}) to avoid warnings on Ruby 2.7
  string.dup.force_encoding(@encoding).encode(:invalid => :replace, :replace => REPLACE)
end

def matching_encoding(string) 

def matching_encoding(string)
  string
end

def remove_invalid_bytes(string)

https://github.com/rubinius/rubinius/blob/v2.5.2/kernel/common/string.rb#L1913-L1972
https://github.com/hsbt/string-scrub
https://github.com/ruby/ruby/blob/v2_1_0/string.c#L8242
https://github.com/ruby/ruby/blob/eeb05e8c11/doc/NEWS-2.1.0#L120-L123 
def remove_invalid_bytes(string)
  string.scrub(REPLACE)
end

def remove_invalid_bytes(string)

for the invalid byte sequence that causes an ArgumentError
with invalid encoding, which is a pretty good proxy
Loop over chars in a string replacing chars
http://stackoverflow.com/a/8711118/879854 
def remove_invalid_bytes(string)
  string.chars.map do |char|
    char.valid_encoding? ? char : REPLACE
  end.join
end

def split(regex_or_string) 

def split(regex_or_string)
  @string.split(matching_encoding(regex_or_string))
rescue ArgumentError
  # JRuby raises an ArgumentError when splitting a source string that
  # contains invalid bytes.
  remove_invalid_bytes(@string).split regex_or_string
end

def split(regex_or_string) 

def split(regex_or_string)
  @string.split(matching_encoding(regex_or_string))
end

def to_s 

def to_s
  @string
end