Thread Safety

[tsofitvail20]

Hi,

We've monkeypatched about thread safety as follows:

        def klass_name
          return @klass_name if defined?(@klass_name)
          @klass_name = name.scan(/(.*)Session/)[0]
          @klass_name = klass_name ? klass_name[0] : nil
        end

https://github.com/binarylogic/authlogic/blob/master/lib/authlogic/session/base.rb#L784

Expected Behavior

The @klass_name will return only after we will extract the klass_name from the array (klass_name[0])

Actual Behavior

When there are multiple calls to the method simultaneously in a multi-threaded context, it happens occasionally that the line:
@klass_name = name.scan(/(.*)Session/)[0]
is executed, and then the other thread reaches the line:
return @klass_name if defined?(@klass_name)
which will return the @klass_name as the intermediate array.

So for example, if name is "UserSession", name.scan(/(.*)Session/)[0] returns ["User"], which is the value received in the other thread.

Suggested solution:
Assign @klass_name in one row will ensure that @klass_name will get value only after we will take out the value from the array.

        def klass_name
          return @klass_name if defined?(@klass_name)
          @klass_name = name.scan(/(.*)Session/)[0]&.first
        end

I'm new to OSS so I'm not comfortable submitting a patch, but I wanted to open an issue so someone can fix this for everyone.

[jaredbeck]

Nice find!

I'm new to OSS so I'm not comfortable submitting a patch ..

Your analysis and solution looks good to me. You were 99% there. Try a PR next time. If you can correctly analyze a threading issue, you can do a PR. Check out "Creating a pull request".