gc.DEBUG_STATS no longer print out anything

[user202729]

Bug report

Bug description:

The command gc.set_debug(gc.DEBUG_STATS) no longer prints out any statistics, even though gc.set_debug(gc.DEBUG_COLLECTABLE) shows that the gc is still being run.

(Probably caused by the incremental GC implementation, #116206 .)

For testing you can use the following code --- in previous Python versions the collecting generation 0 text is printed, now it's not

import gc
import sys
from time import sleep
gc.set_debug(gc.DEBUG_STATS | gc.DEBUG_COLLECTABLE)

for __ in range(3000):
	a=[1]
	a[0]=a
	del a
	print(__)
	sleep(0.001)

sys.exit()

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs

• GH-122298: Restore printing of GC stats #123261
• [3.13] GH-122298: Restore printing of GC stats (GH-123261) #123268

[encukou]

@markshannon Was this intentional?

[hugovk]

Thanks for the fix and backport, let's close if nothing left to do here.