On 14.05.2018 22:05, Ivan Pozdeev wrote:
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 <tjre...@udel.edu
<mailto:tjre...@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
thread-safe.
This means that you didn't (yet) read the letter that I attached to
https://bugs.python.org/issue33479 .
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
https://bugs.python.org/issue33257
* 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).
And another undocumented limitation for threaded Tcl: when calling
anything from outside the interpreter thread, `mainloop()` must be
running in the interpreter threads, or the call will either raise or
hang (dunno any more details atm).
===
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
situations.
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.
Both
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
temporarily.
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.
--
Regards,
Ivan
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