Problem/Motivation
The issue involved the menu_mask variable being empty, resulting in WSOD. This sometimes could result in the inability to install D7/D6.
Proposed resolution
The proposed solution in #33 explains the problem occurring when "2 requests come in at exactly the same time and menu_masks variable is not defined", resulting in the lack of a request lock and the variable remaining undefined. Proposed solution in #53 is RTBC.
Remaining tasks
Comments by mikeytown in #57 in response to webchick in #55 to clarify the solution in the patch comment need review.
User interface changes
none
API changes
none
Original report by [username]
I haev seen too many requests to this and now it came to me that there is a way to rebuild without running a query to see whether router is empty.