Tk Source Code

Run any of the normal file selection dialogs on macOS and this message is printed in the terminal:

objc[16183]: Class FIFinderSyncExtensionHost is implemented in both /System/Library/PrivateFrameworks/FinderKit.framework/Versions/A/FinderKit (0x7fffa5a9ea70) and /System/Library/PrivateFrameworks/FileProvider.framework/OverrideBundles/FinderSyncCollaborationFileProviderOverride.bundle/Contents/MacOS/FinderSyncCollaborationFileProviderOverride (0x10baafcd8). One of the two will be used. Which one is undefined.

The dialog may return a value of a selected file, but Wish will subsequently hang. 

It seems to be more of a macOS system than issue than anything with Wish, but the issue is more than just cosmetic--Wish hangs and must be force-closed. 

Others have reported this issue in other contexts: 

https://stackoverflow.com/questions/46601077/java-exception-since-mac-os-high-sierra

A solution is not clear at this time, but I will do some investigating.

While the warning messages are still appearing on 10.15.6, they do not appear
in Catalina.  In any case they seem to be harmless, if annoying.

With the current tip of core-8-6-branch I see no sign of hangs when using
the file dialog in the widget demo, or in tkdiff.

So I think this problem no longer exists and the ticket can be closed.

Cc'ing myself in case of updates.

Some other mentions of this warning:

• https://groups.google.com/d/msg/comp.lang.tcl/kGbHjKVitx8/l5zfSOMEBQAJ

• https://groups.google.com/d/msg/comp.lang.tcl/3zo9pqLGluM/MYef6JktDwAJ

• https://stackoverflow.com/a/47013488/4896937 (not specific to Tk; answer suggests that the warning can probably be ignored)

• [72eba3264f]

I made a similar experience with 8.6.8 under macOS 10.13.3. The toplevel window that called tk_get*File did not get the focus back. Users of the application reported this as "app not responsive any more".
"focus -force .my_toplevel" solved the issue.

After doing a clean build of 8.6.7, I am not able to reproduce this error consistently. The log message appears, but the file dialogs behave as expected and do not hang. One specific application (the trunk/dev version of TkDiff) does trigger this behavior, but that could be easily the result of an application-specific issues that do not have anything to do with Tk itself.