rubinius/rubinius — pull request #2419 by razielgn (2013-07-04 21:24:34+00:00)
Title: Add spec for String#size with changing of encoding.

The characters number of the string is cached inside `vm/builtin/string.cpp` in num_char. It should be invalidated when the encoding changes, for example because of `String#force_encoding`: with a different encoding, the correlation between characters and bytes may change completely.