Dir#glob and Dir#[] return an array of matching filenames depending upon the parameter.
Example
2.6.5 :001 > Dir.glob("readme.txt")
=> ["readme.txt"]
2.6.5 :002 > Dir.glob(["readme.txt", "test.rb"])
=> ["readme.txt", "test.rb"]Before
With Dir#glob and Dir#[], there is a possibility of unintended file operations because they do not check NULL characters.
2.6.5 :001 > Dir.glob("readme.*\0contributors.*")
(irb):1: warning: use glob patterns list instead of nul-separated patterns
=> ["readme.txt", "contributors.txt"]
2.6.5 :002 >
2.6.5 :003 > Dir["index.html\0show.html"]
(irb):2: warning: use glob patterns list instead of nul-separated patterns
=> ["index.html", "show.html"]In the first example above, the NUL-separated glob pattern readme.*\contributors.*
unexpectedly matches the files based on the patterns readme.* and contributors.*.
The warning that we can notice above, use glob patterns list instead of nul-separated patterns
suggests that we use an array of glob patterns instead of a NUL-separated string.
Ruby 2.7
Ruby 2.7 prohibits NUL-separated glob pattern.
A check has been
added
in this update that raises an ArgumentError if the parameter string contains \0.
2.7.0-preview2 :001 > Dir.glob("readme.*\0contributors.*")
Traceback (most recent call last):
5: from /Users/dexter/.rvm/rubies/ruby-head/bin/irb:23:in `<main>'
4: from /Users/dexter/.rvm/rubies/ruby-head/bin/irb:23:in `load'
3: from /Users/dexter/.rvm/rubies/ruby-head/lib/ruby/gems/2.7.0/gems/irb-1.1.0.pre.3/exe/irb:11:in `<top (required)>'
2: from (irb):1
1: from (irb):1:in `glob'
ArgumentError (nul-separated glob pattern is deprecated)
2.7.0-preview2 :002 >
2.7.0-preview2 :003 > Dir["index.html\0show.html"]
Traceback (most recent call last):
6: from /Users/dexter/.rvm/rubies/ruby-head/bin/irb:23:in `<main>'
5: from /Users/dexter/.rvm/rubies/ruby-head/bin/irb:23:in `load'
4: from /Users/dexter/.rvm/rubies/ruby-head/lib/ruby/gems/2.7.0/gems/irb-1.1.0.pre.3/exe/irb:11:in `<top (required)>'
3: from (irb):2
2: from (irb):3:in `rescue in irb_binding'
1: from (irb):3:in `[]'
ArgumentError (nul-separated glob pattern is deprecated)As we can see, using a NUL-separated string as parameter to Dir#glob or Dir#[] results in
an ArgumentError.
Instead, we should use an array of glob patterns as the parameter.
Example
2.7.0-preview2 :001 > Dir.glob(["readme.*","contributors.*"])
=> ["readme.txt", "contributors.txt"]Above example makes use of an array of glob patterns.
