Bug #8444

Regexp vars $~ and friends are not thread local

Added by James Pharaoh 11 months ago.

[ruby-core:55153]
Status:Open
Priority:Normal
Assignee:-
Category:-
Target version:-
ruby -v:trunk Backport:1.9.3: UNKNOWN, 2.0.0: UNKNOWN

Description

=begin
In the docs for the Regexp special variables, $~ and friends, it says "These global variables are thread-local and method-local variables". However the following gives an unexpected result:

def getproc
proc do |str|
str =~ /(.+)/
sleep 0.1
puts "got #{$1} from #{str}\n"
end
end
proc = get
proc
t1 = Thread.new { proc.call "abc" }
t2 = Thread.new { proc.call "def" }
t1.join
t2.join

This outputs the following:

got abc from abc
got abc from def

The expected result is of course:

got abc from abc
got def from def

Clearly the variables are being scoped to the get_proc method and are being shared by both threads. This runs contrary to the documentation and also to expectations.

This behaviour should either be changed, or the documentation updated to reflect the actual behaviour.

Interestingly, the following does work as expected:

proc = proc do |str|
str =~ /(.+)/
sleep 0.1
puts "got #{$1} from #{str}\n"
end
t1 = Thread.new { proc.call "abc" }
t2 = Thread.new { proc.call "def" }
t1.join
t2.join

=end

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