From: "dunric (David Unric)" <dunric29a@...>
Date: 2013-04-09T17:10:11+09:00
Subject: [ruby-core:54135] [ruby-trunk - Bug #8239] Inline rescue bug


Issue #8239 has been updated by dunric (David Unric).


Hanmac (Hans Mackowiak) wrote:
> its because its parsed as 
> (bar, baz = foo) rescue [3,4]
> i try
> bar, baz = (foo rescue [3,4])
> and this works

I think this explanation is not valid. Let's see on an example:

bar = foo rescue [3,4]
If it would be parsed as you've described it would be equivalent to
(bar = foo) rescue [3,4]
but in contrary the assignment is performed !
ie. bar == [3,4] now.

I did pointed out the issue concerns the case of *multiple* assignment expression.

----------------------------------------
Bug #8239: Inline rescue bug
https://bugs.ruby-lang.org/issues/8239#change-38387

Author: dunric (David Unric)
Status: Open
Priority: Normal
Assignee: matz (Yukihiro Matsumoto)
Category: syntax
Target version: 
ruby -v: 2.0.0p0


There is a possible bug in parsing of inline rescue.
When an inline rescue is a part of multiple assignment and exception is raised, the assignment is silently ignored.

def foo
  raise "error"
end

bar, baz = 1,2    # bar == 1, baz == 2
bar, baz = foo rescue [3,4] # no assignment performed:       bar == 1, baz == 2
                            # expected after the expression: bar == 3, baz == 4

Already discussed at stackoverflow.com:
http://stackoverflow.com/questions/15880136/exceptions-why-does-adding-parenthesis-change-anything


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