Re^2: Populate CGI from HTTP::Request wo/ using %ENV ?

[ikegami]

in reply to Re: Populate CGI from HTTP::Request wo/ using %ENV ?
in thread Populate CGI from HTTP::Request wo/ using %ENV ?

local %ENV doesn't remove the magic attached to %ENV, so changes to %ENV still affect every thread, so the race condition remains.

THREAD 1                                THREAD 2
----------------------------------      ------------------------------
+----
{                                   T
local %ENV;                         i
-> Process's R_M remains undef      m
$ENV{REQUEST_METHOD} = 'GET';       e
-> Process's R_M becomes GET        |
                                    |   {
                                    |   local %ENV;
                                    v   -> Process's R_M becomes undef
                                        $ENV{REQUEST_METHOD} = 'PUT';
                                        -> Process's R_M becomes PUT

print($ENV{REQUEST_METHOD});
-> Prints process's R_M (PUT)
}
-> Process's R_M restored to undef

                                        print($ENV{REQUEST_METHOD});
                                        -> Prints process's R_M (undef
+)
                                        }
                                        -> Process's R_M restored to u
+ndef

That's why I suggested local *ENV instead. Then modifying %ENV doesn't change the processes environment.

Update: Added illustration of two race conditions.