[racket-dev] planet linkage table

From: Robby Findler (robby at eecs.northwestern.edu)
Date: Tue Aug 9 17:23:18 EDT 2011

Somewhere between July 2006 and Dec 2007, the linkage table in planet
broke in such a way that it has been just ignored for around 4 years
now. I just noticed this today [*] as I was spending some time trying
to make the planet module name resolver thread safe.

So, my question to you: should we bring this feature back? Did anyone
notice it was gone?

If you're curious what this is about, probably the best thing to read
is this paper, specifically the linkage table is what the last
paragraph under the heading "The magic upgrade problem" on page 163
discusses:

  http://people.cs.uchicago.edu/~jacobm/pubs/planet.pdf

Thanks,
Robby

[*] There was a (with-handlers ((exn:fail? (lambda (e) #f))) ...)
wrapped around some code that was implementing part of the lookup in
the table and the exception handler was catching what amounts to a
refactoring bug, instead of the parsing error reading the file that it
seems to have been designed to catch and, of course, there were no
test cases that the linkage thingy was working properly. So, learn
from this old-ish man's mistakes and don't do either of those
things....


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