IO.open with three arguments where third argument is bogus reports an arity problem instead of type problem
|ruby -v:||ruby 2.0.0dev (2013-02-08 trunk 39161) [x86_64-darwin11.4.2]||Backport:|
I am reporting this against 2.0.rc2 but it also applies to mri 1.9.3. If I run the following one-liner:
mri20 -e 'f = File.open("tmp"); IO.open(f.fileno, "r", :heh)'
I get the error:
-e:1:in `initialize': wrong number of arguments (3 for 1..2) (ArgumentError)
This seems wrong because if I change the third argument to an options hash it works fine. So having an arity of 3 is not a problem for open. It is that :heh is not a hash. I think this should generate a TypeError.
#1 Updated by Eric Hodel over 2 years ago
- Category set to core
- Target version set to next minor
Since Ruby 1.9.3p374 has the same behavior I have marked this for next minor:
$ ruby19 -ve 'f = File.open("tmp"); IO.open(f.fileno, "r", :heh)'
ruby 1.9.3p374 (2013-01-15 revision 38858) [x86_64-darwin12.2.1]
initialize': wrong number of arguments (3 for 1..2) (ArgumentError)open'
from -e:1:in `'
#2 Updated by Nobuyoshi Nakada over 2 years ago
- Status changed from Open to Rejected
It's common behavior to keyword arguments,
$ ruby -e 'def foo(a, b, c:1);end' -e 'foo(2,3,42)'
foo': wrong number of arguments (3 for 2) (ArgumentError)'
The optional argument hash is stripped before arity check, so it's "invisible" as arity.