Note that Dir.glob('*', File::FNM_CASEFOLD), Dir.glob('a*', File::FNM_CASEFOLD) and Dir.glob('*a') work, so it is a bit strange that Dir.glob('*a', File::FNM_CASEFOLD) does not.
Not sure if it can be removed, but I think you can change the status
to "closed" (or someone from the ruby core team probably could).
To the bug report, just out of curiosity, can you avoid the UTF
problem if you change to use another encoding before calling
Dir.glob? For example, I usually use 'ISO-8859-1' mostly due to
german umlauts but the terminal/shell used, such as my case
usually mate-terminal (based on vte) these days, there is also an
option where I can decide to use UTF-8 as locale, or the current
active locale (ISO-8859-1). When I use both ISO and the locale
setting, I almost never get invalid byte sequence errors (and
of course if I sync any external input read... File.read() has
an option for specifying the :encoding, perhaps Dir.glob()
could also benefit from a hash with a key called :encoding but
I am perhaps digressing...)
This is still an issue in the master branch. The problem can be solved by actually ignoring File::FNM_CASEFOLD, which is something that the Dir.glob documentation says that it does. I've submitted a pull request that fixes this: https://github.com/ruby/ruby/pull/4583
This was already documented as being ignored, but it wasn't being
ignored, causing an issue in a particular case where a UTF-8
pattern was provided and a filename was tested that wasn't valid
UTF-8.
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Updated by jeremyevans (Jeremy Evans)