importing the same module over and over eats up more and more memory

[sjamaan]

Reported by "plugd" on IRC:

(import (chicken string)
        (chicken gc)
        (chicken io))

(let loop ()
  (print (conc "Memory statistics: " (memory-statistics)))
  (eval '(begin (import (chicken string)) (print "Hello.")))
  (read-line)
  (loop))

I checked, and CHICKEN 4 also exhibits this behaviour, so it's not something new we recently introduced (as I remember we've been putting some effort into optimizing library imports)

[sjamaan]

Ah, the optimization mentioned in the description was in merge-se, which ##sys#import does *not* use: it uses append, which is a bit of a naive way of extending the current environment. It's fine for locally scoped lets and such, which the compiler and interpreter do all over the place, but it's not fine when adding large amounts of identifiers in one go to an open-ended environment like import does.

The fix is to call merge-se; patch sent to chicken-hackers. Moving to the 5.3 milestone unless anyone objects.

[sjamaan]

Fixed with ff8a66a7bb180d7dce6c9a6d7cb3e5d6cb53c985