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BUG: chr() leaks #4422
Description
#
# to run with small heap eg -X heapsize=16384
#
try:
import utime as time
except:
import time
import gc
cnt = 1
last = 0
while cnt < 0x110000:
time.sleep(.005)
current = gc.mem_free()
#GOOD print( '[%c]' % cnt , current - last, current )
#BAD print( '{}'.format( chr(cnt) ), current - last, current )
#BAD
print( chr( cnt ), cnt , current - last, current )
cnt +=1
last = current
gc.collect() #no effect maybe a useless volatile interned strings of length 1 somewhere ?
Activity
pfalcon commentedon Jan 22, 2019
pmp-p commentedon Jan 22, 2019
Title is explicit enough no ?
run code, enjoy MemoryError after a while on any port, unix port is good enough for that or pycopy with a esp sized heap.
edit / finally on a side note i spent 4 hours finding that and sent issue in a hurry before work, so you could give a 30 seconds to at least test the snippet instead of writing your own. if i'm wrong i will deeply apologize for wasting your precious time.
pfalcon commentedon Jan 22, 2019
Look how much info can be packed into human words ;-).
Good mentioning, because aggressive string interning introduced by @dpgeorge was one of the few patches I reverted (so far) in my fork.
But otherwise, yeah, looking at mp_builtin_chr(), it interns unconditionally. A solution would be interning only ASCII stuff by default, allow to disable interning in optional cases (like this) altogether.
pmp-p commentedon Jan 22, 2019
"unconditionally" => that may explain why my doubts probably left me speechless at first.
pfalcon commentedon Jan 22, 2019
Obviously the opposite. And quite obviously actually:
pmp-p commentedon Jan 22, 2019
by short i meant len() < sizeof( hash + storage pointer )
peterhinch commentedon Jan 22, 2019
See #2280.
pmp-p commentedon Jan 22, 2019
thx for incrementing the reference counter ;)
pmp-p commentedon Jan 24, 2019
a tested working fix is available here https://github.com/pfalcon/pycopy/commit/4d7a02654d37024d73f83d47f992f2dd91e2d8b7.diff
[-]chr() leaks[/-][+]BUG: chr() leaks[/+]IncrementalEncoder: support swapped pins
jonnor commentedon Sep 19, 2024
No MemoryError when running this on Unix port with version v1.24.0-preview.276.g1897fe6227. But it seems to stop at
which seems way to early?