gedit freezes when opening PHP file with long lines

[Jaromir Obr]

Steps:
* Download https://github.com/vrana/adminer/releases/download/v4.7.4/adminer-4.7.4.php (485 kB)
* Open it in gedit

Expected result:
* It takes a few seconds. E.g. in Visual Studio Code editor it takes max 10 sec

Actual result:
* File isn't open even in a few minutes
* I'm only getting a dialog "Text Editor not responding" with the buttons "Wait" and "Force quit".
* Unfortunately neither "Wait" or "Force Quit" is working and Gnome stops responding, so I have to switch to text console by Ctrl + Alt + F4 and kill the gedit process. But then often when I switch back to Gnome desktop, it's still not responding (e.g. neither clicking to any application nor keyboard is working) and I have to restart OS.

Used SW:
* Ubuntu 19.10
* gedit 3.34.0-1

ProblemType: Bug
DistroRelease: Ubuntu 19.10
Package: gedit 3.34.0-1
ProcVersionSignature: Ubuntu 5.3.0-19.20-generic 5.3.1
Uname: Linux 5.3.0-19-generic x86_64
ApportVersion: 2.20.11-0ubuntu8
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Sun Oct 27 14:34:07 2019
InstallationDate: Installed on 2015-12-29 (1397 days ago)
InstallationMedia: Ubuntu 15.10 "Wily Werewolf" - Release amd64 (20151021)
SourcePackage: gedit
UpgradeStatus: No upgrade log present (probably fresh install)

[Paul White (paulw2u)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug 505765, so it is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report.

Feel free to continue to report any other bugs you may find.

[Daniel van Vugt (vanvugt)]

The gnome-shell part of this bug might related to bug 1845302.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Sebastien Bacher (seb128)]

closing the gedit part since it's already reported as mentioned in the previous comments

[Sebastien Bacher (seb128)]

Could you test if the update on the other bug mentioned fixes the issue?

[Jaromir Obr (jaromir-obr)]

As for the issue with non responsive gnome shell (bug 1845302), I hope the fix in Mutter will be delivered to Ubuntu 19.10 (where it's broken from my point of view). And then I'm able to test it.

[Jaromir Obr (jaromir-obr)]

I've just verified a fix of the gnome-shell part of this issue in bug 1845302.