[Python-Dev] bpo-33257: seeking advice & approval on the course of action
On 14.05.2018 21:58, Terry Reedy wrote:
> On 5/14/2018 12:20 PM, Chris Barker via Python-Dev wrote:
>> On Wed, May 2, 2018 at 8:21 PM, Terry Reedy <tjreedy at udel.edu
>> <mailto:tjreedy at udel.edu>> wrote:
>> ??? On 5/2/2018 4:38 PM, Ivan Pozdeev via Python-Dev wrote:
>> ??????? The bottom line is: Tkinter is currently broken
>> ??? This is way over-stated.? Many modules have bugs, somethings in
>> ??? features more central to their main purpose.
>> I'll suggest a re-statement:
>> tkinter is not thread safe,
> Still over-stated.? If one uses tcl/tk compiled with thread support,
> tkinter *is* thread-safe.? This is 'as far as I know' from running
> posted 'failing' examples (possible with bug fixes) with 3.5+ on
> Windows, which is installed with tcl/tk 8.6, which defaults to
This means that you didn't (yet) read the letter that I attached to
Reciting the relevant section:
The reality is that with neither flavor of Tcl is Tkinter completely
thread-safe, but with threaded flavor, it's more so:
* with nonthreaded Tcl, making concurrent Tcl calls leads to crashes due
to incorrect management of the "Tcl lock" as per
* with threaded Tcl, the only issue that I found so far is that a few
APIs must be called from the interpreter's thread
(https://bugs.python.org/issue33412#msg316152; so far, I know
`mainloop()` and `destroy()` to be this) -- while most can be called
from anywhere. Whether the exceptions are justified is a matter of
discussion (e.g. at first glance, `destroy()` can be fixed).
> Tkinter was intended to also be thread-safe when using tcl/tk without
> thread support, which was the default for tcl/tk 8.5 and before. The
> posted examples can fail on 2.x on Windows, which comes with tcl/tk
> 8.5 or before. _tkinter.c has some different #ifdefs for the two
>> and yet it is documented as being thread safe
> True in https://docs.python.org/3/library/tk.html
> Unspecified in https://docs.python.org/3/library/tkinter.html
>> This is either a bug(s) in the implementation or the docs.
>> So what are the solutions?
>> 1) fix the docs -- unless tkInter is made thread safe really soon,
>> and fixes are back-ported, this seems like a no brainer -- at least
> https://bugs.python.org/issue33479 'Document tkinter and threads'
>> 2) fix the issues that make tkInter not thread safe
> with non-thread tcl/tk.
> https://bugs.python.org/issue33257 has a patch that might improve the
> situation for one type of call.? Fixing everything might not be
> possible.? AFAIK, there are currently no tests of thread safety.