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Tkinter not installed correctly on Windows 3.15.0b2 #150836
Description
Bug report
Bug description:
3.15.0b1 was fine. 3.15.0b2 will not start tk/tcl. Difference must be incomplete upgrade to tk 9.0.
If I run the REPL with either the Start icon or py in a console, import tkinter works but a subsequent t = tkinter.Text() fails with
Traceback (most recent call last):
File "<python-input-2>", line 1, in <module>
t = tkinter.Text()
File "C:\Programs\Python315\Lib\tkinter\__init__.py", line 3857, in __init__
Widget.__init__(self, master, 'text', cnf, kw)
~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Programs\Python315\Lib\tkinter\__init__.py", line 2853, in __init__
self._setup(master, cnf)
~~~~~~~~~~~^^^^^^^^^^^^^
File "C:\Programs\Python315\Lib\tkinter\__init__.py", line 2818, in _setup
master = _get_default_root()
File "C:\Programs\Python315\Lib\tkinter\__init__.py", line 330, in _get_default_root
root = Tk()
File "C:\Programs\Python315\Lib\tkinter\__init__.py", line 2535, in __init__
self.tk = _tkinter.create(screenName, baseName, className, interactive, wantobjects, useTk, sync, use)
~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
_tkinter.TclError: Can't find a usable tk.tcl in the following directories:
//zipfs:/app/tk_library //zipfs:/lib/tk/tk_library //zipfs:/lib/tk //zipfs:/lib/tcl/tcl_library/tk9.0 //zipfs:/lib/tcl/tk9.0 C:/Programs/lib/tk9.0 C:/Programs/lib/tk9.0 C:/lib/tk9.0 C:/Programs/libraryThis probably means that tk wasn't installed properly.
The IDLE icon in the start menu does not work. If I pin it to taskbar and click, the blue circle starts and quickly stops. The one for older versions start, quickly stop, and quickly restart until IDLE runs. In a console, py -m idlelib fails at the same _tkinter.create(...) call with the same message.
I have seen a similar message before and I believe the list of directories is obsolete. In a local build, I believe the tcl/tk file needs to be in PCbuild/. My 3.16 build works fine. Installations used to have DLLs/tcl86t.dll and tk86t.dll. 3.15.0b2 has tcl9tk90.dll and tcl90.dll (no t suffix). Is _tkinter.dll looking for those names?
CPython versions tested on:
3.15
Operating systems tested on:
Windows
Activity
terryjreedy commentedon Jun 5, 2026
@jjhelmus "I was able to get Tkinter working with an install of 3.15.0b2 on Windows by adjusting the files in the tcl directory."
This works. It makes tcl/ look similar to what it did with 8.6. Thank you for the patch. Just curious, does it make tkinter run with compressed zip instead of expanded files?
I installed from old-style download ...64.exe. I presume same failure with new installer.
@nibedanmohanta9-arch A correct version-specific pip command would be
py -3.15 -m pip install <package>. Tkinter is not an installable package. Please test before posting.zooba commentedon Jun 8, 2026
I'd also be interested to see how the fix looks that allows using the embedded ZIPs. For places where we are bundling 3rd party binaries, being more accepting of different builds of those binaries is better than merely fixing our own build - other people may be rebuilding from sources, and letting them have choices without having to patch our actual sources is better.
hugovk commentedon Jun 15, 2026
How is the PR looking for this release blocker? The next release is next week.
zooba commentedon Jun 15, 2026
My last question still stands - if we can fix this in Tkinter rather than in our build commands for our own copy of Tcl, I think that would be better.
pythongh-150836: Mount embedded Tk ZIP in _tkinter on Windows
jjhelmus commentedon Jun 16, 2026
This can be address in
_tkinterby attempting to mount the Tk DLL as a a zipfs with a location thattcl_findLibrarysearches (e.g. //zipfs:/lib/tk). If the DLL has an embedded tk_library then it will be found, if not the mount will be ignored and the existing behavior proceeds.#151562 implements this change.
zooba commentedon Jun 17, 2026
Thanks @jjhelmus, I like how that looks, and it ought to be more future proof, if I understand correctly? Interested in others' thoughts as well.
I'll leave a comment or two on that PR, since I think it's worth making it ready to merge, but my other big question is whether this should be used on all platforms? Is this a Windows-only feature from Tcl, or is there benefit to mounting it on all OSs?
jjhelmus commentedon Jun 18, 2026
I suspect other platform would benefit from mounting the Tk DSO/DLL if it contained an embedded tk_library. Especially if the CPython install is relocated or determined at install time rather that build time. I need to do some testing to see if the current situation causes problems. Most distributions I know of either us a hardcoded path to the Tk library (e.g. Linux distro provided CPython) or disable embedding (python-build-standalone, MacPorts) which avoids the issue seen here.
jjhelmus commentedon Jun 18, 2026
I tested out linking Tcl/Tk with embedded library on both macOS and Linux in python-build-standalone and neither have issues with Tkinter, it seems like this issue is limited to Windows.
Specifically Tcl uses the executable relative fallback in
tcl_findLibraryto find the DSOs with the embedding in<prefix>/libwhen the executable (python) is in<prefix>/bin.zooba commentedon Jun 19, 2026
Well, it sounds like @jjhelmus has the only opinion here (other than me), so let's go with doing the mount on Windows only and see what comes out of it.
gh-150836: Mount embedded Tk ZIP in _tkinter on Windows (GH-151562)
[3.15] gh-150836: Mount embedded Tk ZIP in _tkinter on Windows (GH-15…
hugovk commentedon Jun 22, 2026
Thanks all, I've removed the release-blocker label.
zooba commentedon Jun 22, 2026
Closing this as completed, we can reopen if it is still busted.
terryjreedy commentedon Jun 22, 2026
IDLE is working fine. There is still an open PR. Was it superceded? Should it be closed?
zooba commentedon Jun 22, 2026
Yes, and not yet (unless you're confident enough that this fix will work after install to go and close the other one).
pythongh-150836: Mount embedded Tk ZIP in _tkinter on Windows (python…
pythongh-150836: Mount embedded Tk ZIP in _tkinter on Windows (python…