From: tenderlove@...
Date: 2017-02-18T01:55:44+00:00
Subject: [ruby-core:79583] [Ruby trunk Bug#13223] `File.join` will segv if File::SEPARATOR and File::Separator are set.

Issue #13223 has been updated by Aaron Patterson.


@nobu I went by what the documentation says:

~~~
/*
 *  call-seq:
 *     File.join(string, ...)  ->  string
 *
 *  Returns a new string formed by joining the strings using
 *  <code>File::SEPARATOR</code>.
 *
 *     File.join("usr", "mail", "gumby")   #=> "usr/mail/gumby"
 *
 */
~~~

The current implementation doesn't seem to care what the value of `File::SEPARATOR` is, so I think it's a bug.  Also JRuby has this behavior:

~~~
$ jruby -v -e'File.const_set(:SEPARATOR, "$"); p File.join("a","b")'
jruby 9.1.6.0 (2.3.1) 2016-11-09 0150a76 Java HotSpot(TM) 64-Bit Server VM 25.77-b03 on 1.8.0_77-b03 +jit [darwin-x86_64]
-e:1: warning: already initialized constant SEPARATOR
"a$b"
~~~

----------------------------------------
Bug #13223: `File.join` will segv if File::SEPARATOR and File::Separator are set.
https://bugs.ruby-lang.org/issues/13223#change-63013

* Author: Aaron Patterson
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: ruby 2.5.0dev (2017-02-17 trunk 57648) [x86_64-darwin16]
* Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN
----------------------------------------
The program below will crash with a segv:

~~~ruby
File.const_set :Separator, "hello"
File.const_set :SEPARATOR, "hello"

GC.start

File.join "hello", "world"
~~~

This is because the separator object is referenced from a global variable and setting the constants allows the object to be GC'd and the global will go bad.

I've attached a patch that contains a test to demonstrate the problem along with a fix.

---Files--------------------------------
0001-Fix-segv-in-File.join-when-SEPARATOR-and-Separator-a.patch (3.04 KB)


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