Issue 30642: Fix leaks in idlelib (original) (raw)

When Louie Lu posted a link to https://blog.louie.lu/2017/06/12/diagnosing-and-fixing-reference-leaks-in-cpython/ on core-mentorship list, I tested idlelib. python -m test -ugui test_idle # SUCCESS, no extraneous output python -m test -R: test_idle # SUCCESS, no extraneous output python -m test -R: -ugui test_idle # error output, FAILURE [So people who leaktest without a screen see nothing in idlelib.]

Error output is about 20 copies of the following: can't invoke "event" command: application has been destroyed while executing "event generate $w <>" (procedure "ttk::ThemeChanged" line 6) invoked from within "ttk::ThemeChanged"

At the end: test_idle leaked [471, 471, 471, 471] references, sum=1884 test_idle leaked [209, 211, 211, 211] memory blocks, sum=842 [similar for python 3.6]

In a response email, I noted that test_idle gathers tests from idlelib.idle_test.test_* and that something extra is needed to pin leaks to specific test modules.

I don't know whether the absence of 'invoke event' error messages when not running -R means that there are also no refleaks, or not.

import os import subprocess

os.chdir('f:/dev/3x/Lib/idlelib/idle_test') testfiles = [name for name in os.listdir() if name.startswith('test_')] for name in testfiles: os.rename(name, 'x'+name) for name in testfiles: os.rename('x'+name, name) try: res = subprocess.run( ['f:/dev/3x/python.bat', '-m', 'test', '-R:', '-ugui', 'test_idle'], stdout=subprocess.PIPE, stderr=subprocess.PIPE) if res.returncode: print(name) print(res.stderr) except Exception as err: print(name, err) os.rename(name, 'x'+name) for name in testfiles: os.rename('x'+name, name)

reports test_macosx.py b'beginning 9 repetitions\r\n123456789\r\n\r\ntest_idle leaked [31, 31, 31, 31] references, sum=124\r\ntest_idle leaked [19, 21, 21, 21] memory blocks, sum=82\r\n' test_query.py b'beginning 9 repetitions\r\n123456789\r\n\r\ntest_idle leaked [429, 429, 429, 429] references, sum=1716\r\ntest_idle leaked [190, 192, 192, 192] memory blocks, sum=766\r\n' There are no 'invoke event' messages.

For further testing within each file, by commenting out code, as suggested in the link above, I replaced 'testfiles' in the middle loop with ['testmacosx.py'] or ['test_query.py']. For test_macosx, the culprit is class SetupTest. For test_query, the culprit is class QueryGuiTest. Adding cls.root.update_idletasks did not solve the problem by itself (as it has in other cases). I plan to continue another time.

The macosx leak came from repeated calls to root.createcommand("::tk::mac::OpenDocument", doOpenFile) in macosx.addOpenEventSupport(root, flist), which is called from macosx.setupApp, which is called in test_macosx.SetupTest.test_setupapp.

Attached is an improved version of findleak.py, which made it easy to isolate one test file by renaming, repeatedly determine whether the leak remained after modifying either macosx.py or test_macosx.py, and revert all the other names when done.