[ruby-core:67770] [ruby-trunk - Bug #10777] [Open] variable gets reset when passing a named argument to a function, if the name of this argument is the same as variable name

[ruby-core:67770] [ruby-trunk - Bug #10777] [Open] variable gets reset when passing a named argument to a function, if the name of this argument is the same as variable name

[ofajans]

Issue #10777 has been reported by Oleg Fayans.

----------------------------------------
Bug #10777: variable gets reset when passing a named argument to a function, if the name of this argument is the same as variable name
https://bugs.ruby-lang.org/issues/10777

* Author: Oleg Fayans
* Status: Open
* Priority: Normal
* Assignee: Yukihiro Matsumoto
* ruby -v: ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-linux]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
----------------------------------------
I have a function, say function1 that has a variable, named param with a value of true.
from this function I call another function, function2 with the following call:
function2(param=false)
During this call the value of param in function1 gets changed to false, which absolutely should not happen.
Example code:

def func2(param=nil)
   puts "param in func2 is #{param}"
end

def func1(param="Hello")
   puts param
   func2(param="Goodbye")
   puts "param in func1 is #{param}"
end


> func1
Hello
param in func2 is Goodbye
param in func1 is Goodbye
 => nil

The same in a pastebin:
http://pastebin.mozilla.org/8315338

This behavior is observed also in ruby-1.9.3-p545



-- 
https://bugs.ruby-lang.org/

[ruby-core:67771] [ruby-trunk - Bug #10777] [Rejected] variable gets reset when passing a named argument to a function, if the name of this argument is the same as variable name

[eregontp]

Issue #10777 has been updated by Benoit Daloze.

Status changed from Open to Rejected

This is not Python ;)
= is assignment, or in method declarations indicates the default value for an argument.
So `func2(param="Goodbye")` is effectively the same as

    param="Goodbye"
    func2(param)

which makes the current behavior meaningful.

If you want keyword arguments, the syntax is

    def func2(param: nil)
      ...
    end

    func2(param: "Goodbye")

And this will not affect the param local variable.

----------------------------------------
Bug #10777: variable gets reset when passing a named argument to a function, if the name of this argument is the same as variable name
https://bugs.ruby-lang.org/issues/10777#change-51194

* Author: Oleg Fayans
* Status: Rejected
* Priority: Normal
* Assignee: Yukihiro Matsumoto
* ruby -v: ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-linux]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
----------------------------------------
I have a function, say function1 that has a variable, named param with a value of true.
from this function I call another function, function2 with the following call:
function2(param=false)
During this call the value of param in function1 gets changed to false, which absolutely should not happen.
Example code:

def func2(param=nil)
   puts "param in func2 is #{param}"
end

def func1(param="Hello")
   puts param
   func2(param="Goodbye")
   puts "param in func1 is #{param}"
end


> func1
Hello
param in func2 is Goodbye
param in func1 is Goodbye
 => nil

The same in a pastebin:
http://pastebin.mozilla.org/8315338

This behavior is observed also in ruby-1.9.3-p545



-- 
https://bugs.ruby-lang.org/