Tkinter - Unexpected behavior after creating around 10000 widgets

[jlahav]

BPO	41632
Nosy	@serhiy-storchaka, @E-Paine
Files	ten_k.py: code sample ten_k.tcl

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2020-08-26.11:22:15.315>
created_at = <Date 2020-08-25.12:23:41.559>
labels = ['3.8', 'expert-tkinter', 'type-crash']
title = 'Tkinter - Unexpected behavior after creating around 10000 widgets'
updated_at = <Date 2020-08-26.11:22:15.314>
user = 'https://bugs.python.org/jlahav'

bugs.python.org fields:

activity = <Date 2020-08-26.11:22:15.314>
actor = 'serhiy.storchaka'
assignee = 'none'
closed = True
closed_date = <Date 2020-08-26.11:22:15.315>
closer = 'serhiy.storchaka'
components = ['Tkinter']
creation = <Date 2020-08-25.12:23:41.559>
creator = 'j.lahav'
dependencies = []
files = ['49426', '49427']
hgrepos = []
issue_num = 41632
keywords = []
message_count = 3.0
messages = ['375888', '375889', '375899']
nosy_count = 4.0
nosy_names = ['gpolo', 'serhiy.storchaka', 'epaine', 'j.lahav']
pr_nums = []
priority = 'normal'
resolution = 'third party'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'crash'
url = 'https://bugs.python.org/issue41632'
versions = ['Python 3.8']

[jlahav]

Observation:
After creating around 10000 widgets (verified with ttk.Label), no more widgets get created, and sometimes graphical artifacts appear outside the application window.

No error message or exception is raised.

Expected:
Either the limit can be removed (having dynamically created 10000 widgets in data heavy applications is sometimes desired), or at least document and return runtime errors to prevent the weird behavior.

Reproduction:
This is the problematic part:
for _ in range(10000):
ttk.Label(root, text='problematic')

A full minimal example code is attached, though a better effect can be seen when running the above two lines in the context of a more advanced Tkinter application.

[E-Paine]

I am struggling to reproduce. On Linux the window shows exactly as expected (it does take a while to close, though, which is understandable) and on Windows the window never shows (it gets stuck before the mainloop). This is, however, not a tkinter problem as I get exactly the same result on each platform running the following equivalent Tcl in Wish:

for {set i 0} {$i < 10000} {incr i} {
    ttk::label ".l$i" -text problematic
}
grid [ttk::label .lb -text {now you see me}]

A similar issue was reported in bpo-37673. If you *need* lots of widgets (e.g. a large table) I would suggest lazy loading them instead of trying to render them all at load. Thank you for reporting this issue but it should be closed as third-party.

A note for future: please could you include information about your environment (Python version, Tk patchlevel, OS, etc.) so it is easier for the problem to be narrowed down (again, thank you for reporting this issue).

[jlahav]

Thank you for checking it so quickly, and answering nicely.

I indeed forgot to mention that it happened to me on Windows. Sorry for that.

The issue seems similar to the one you linked. I will try and take this to the TCL community since it impacts our product. Thank you for translating the code to TCL.

If the python community has no interest in trying to push TCL to fix it, this issue can be closed.

Thanks!