Linux: FreeFileSync using GTK3 on KDE is hanging

[drak]

Hi,

Love FFS. The Donation edition broke on me after today's update.
Clicking any buttons or trying to open FFS preferences leads to a full freeze of the app, and requires xkilling.

System Plasma 5.27.0
Kernel: 5.19.0-32-generic

I installed free flatpak version, and rejected the update, and managed to sync that way but would appreciate being faster ;)

Cheers thanks, all the best

[Crustyman]

I have the same problem, +1. Just freezes.

System: endeavoros
DE: KDE plasma 5.27.1
Kernel: 6.1.12
gtk3 version: 3.24.36-1

[fefisy]

+1

Operating System: Kubuntu 22.04
KDE Plasma Version: 5.24.7
KDE Frameworks Version: 5.98.0
Qt Version: 5.15.3
Kernel Version: 5.15.0-60-generic (64-bit)

libgtk-3.0 version 3.24.33-1ubuntu2

[Zenju]

This is due to the switch to GTK3 and seems to affect KDE only.

Let's test something. Are the hangs reproducible if you start FreeFileSync via command line as

GDK_SYNCHRONIZE=1 FreeFileSync


?

[Crustyman]

Yes, nothing changes

[daviank]

It seems I have a similar problem on debian with KDE, when built from source.
BTW, the Makefile still references gtk2, is this as expected or should it be gtk3 now?

[fefisy]

This is due to the switch to GTK3 and seems to affect KDE only.

Let's test something. Are the hangs reproducible if you start FreeFileSync via command line as

GDK_SYNCHRONIZE=1 FreeFileSync


?

This worked for me as expected. No hangs.
However, also got this:

(FreeFileSync_x86_64:246593): Gtk-CRITICAL **: 17:29:57.211: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GtkScrollbar


[fefisy]

This worked for me as expected. No hangs.
However, also got this:

(FreeFileSync_x86_64:246593): Gtk-CRITICAL **: 17:29:57.211: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GtkScrollbar


Update: When launched from FreeFileSync.desktop containing the following...

Exec=GDK_SYNCHRONIZE=1 "/opt/FreeFileSync/FreeFileSync" %F


...I was able to perform several sync actions without hangs, but not consistently. The application still hangs intermittently and has to be killed and restarted.

[Zenju]

I've reverted FFS back to GTK2 until this issue has been sorted out.

FFS does a peculiar little dance during modal dialog initialization:

    GetSizer()->SetSizeHints(this); //~=Fit() + SetMinSize()
#ifdef __WXGTK3__
    Show(); //GTK3 size calculation requires visible window: https://github.com/wxWidgets/wxWidgets/issues/16088
    Hide(); //avoid old position flash when Center() moves window (asynchronously?)
#endif
    Center(); //needs to be re-applied after a dialog size change!


I suspect the Show/Hide pair is triggering the hang, which is most likely nothing more than a hidden modal dialog.

Perhaps someone has an idea why FFS hangs on GTK3 and KDE? Or knows a better way to coerce GTK3 to set correct window sizes?

[drak]

Just saw the update and tried it, it successfully opened one dialog but then froze after trying to open a second one. I wish I knew how to be more helpful :')

I can cheer ;)

[fefisy]

I've reverted FFS back to GTK2 until this issue has been sorted out.

Is this going to be available for download/installation, or should I download and install 12.0?

[Zenju]

The official FFS 12.1 has been replaced with the GTK2 build again.

[drak]

My installation that auto-updated to the problematic version, is not notifying of an update to pull the GTK2 build. Please, thank you.

[fefisy]

My installation that auto-updated to the problematic version, is not notifying of an update to pull the GTK2 build. Please, thank you.

Manually download and install using NON-donation 12.1 installer. I found that the donation edition has gtk3.

[daviank]

Zenju, reverting the change you mention apparently removes the issue (still built with GTK3).

For anyone interested, a patch for this revert is available here: https://salsa.debian.org/bastif/freefilesync/-/blob/debian/latest/debian/patches/revert_buggy_gtk3_change_in_12.1.patch

[Zenju]

Manually download and install using NON-donation 12.1 installer. I found that the donation edition has gtk3.

How did you determine that? The build should be GTK2-based.

[drak]

I haven't tried redownloading the donation version. Let me know if that's best Zenju, thank you for keeping up with this I really appreciate it.
EDIT: Missed the patch somehow, don't know how to apply it though, thanks for the help in advance

[drak]

Can someone please tell me exactly how to apply this patch? Thank you so much.

[fefisy]

Manually download and install using NON-donation 12.1 installer. I found that the donation edition has gtk3.

How did you determine that? The build should be GTK2-based.

Well, this is what I saw:
1. Downloaded 12.1 donation edition installer when I first saw the update notification. After installing this, I saw the GTK3 issue reported in this thread.
2. Upon learning that 12.1 was rolled back to GTK2, I downloaded the donation edition installer again and re-installed. I continued to see the GTK3 issue.
3. I then downloaded and ran the non-donation 12.1 installer. Now I don't see the GTK3 issue.

[daviank]

Dear Zenju, I have been investigating this a bit since I run on KDE, which caused trouble with gtk3 at the time of 12.1.

Actually, I found that calling only Show() but not Hide() as code currently does since 12.1:
- doesn't create the "freeze/hang" on KDE that appeared in 12.1
- fixes the size of the dialogs (see screenshots)
- there is no flickering on screen

However, I can't test this on other desktop environments like Gnome or any other because I run KDE.

Would that be an acceptable solution for that problem? Do you think this could be integrated in your sources?

The old way (ie. the GTK2 way built with GTK3 (=like the patch I put earlier in this thread))

Screenshot_20240206_225342.png (4.59 KiB) Viewed 1158 times

The new way (ie. with the "patch" attached in this post)

Screenshot_20240206_224208.png (5.17 KiB) Viewed 1158 times

The patch (it has .txt extension, but it should have .patch)

fix-gtk3-kde-hang.txt

(9.25 KiB) Downloaded 532 times

[Zenju]

Dear Zenju, I have been investigating this a bit since I run on KDE, which caused trouble with gtk3 at the time of 12.1.

Actually, I found that calling only Show() but not Hide() as code currently does since 12.1:
- doesn't create the "freeze/hang" on KDE that appeared in 12.1
- fixes the size of the dialogs (see screenshots)
- there is no flickering on screen

I've commented out the Hide()s. This seems to fix the "hangs" on KDE, which are nothing more than the windows staying hidden after a "Hide(); Show()" sequence. GTK3 with all its asynchronicity seems to be responsible for this mess.
GDK_SYNCHRONIZE=1 seems to mitigate this issue by about 80%, but it's still reproducible!

Drawback: Without the "Hide()" the old position flashes shortly before "Center" on Gnome, which looks really ugly. GTK3, unfortunately is still not ready for prime time.

[daviank]

BTW, I noticed that in the About dialog, only the last Show() must be kept. Having both leads to corruption in the dialog (at the location of the donation text + image)