Bug: replacing cell contents after executing

[lesliewalcott]

Description

When I execute a cell by hitting "shift enter", the cell executes, but the cell contents is replaced with the previous cell that I ran.

Example:
In: print("hi")
Out: hi

In: 2+2
Out: 4

Upon executing, the "2+2" in my cell is replaced with "print("hi")". I took a few videos illustrating this with my actual code: https://imgur.com/a/TzifF5k

It always replaces the cell input with the last cell that was executed. If I were to run an additional cell:
In: print("Hello")
Out: Hello

It would print Hello, but also replace the cell input with "2+2".

Reproduce

This has happened to me at random. It happened about a month ago and I fixed it by rebooting my machine. Today it happened again and I fixed it by restarting the kernel and clearing all outputs (rebooting did NOT fix it). I have searched online to see if this happened to anyone else, but didn't find anything, so I wanted to report it here.

Expected behavior

I expect the cell to be executed, and the code that I typed in to not change.

Context

• Operating System and version: Amazon Linux AMI 2018.03
• Browser and version: Chrome 79.0.3945.130
• JupyterLab version: 4.4.0

Troubleshoot Output

$PATH:
        /home/ec2-user/anaconda3/envs/DS-CUSTOMER-DISCOVERY/bin
        /home/ec2-user/anaconda3/envs/DS-CUSTOMER-DISCOVERY/bin
        /home/ec2-user/anaconda3/bin
        /usr/local/bin
        /bin
        /usr/bin
        /usr/local/sbin
        /usr/sbin
        /sbin
        /opt/aws/bin
        /home/ec2-user/.local/bin
        /home/ec2-user/bin
        /home/ec2-user/anaconda3/bin
        /opt/aws/bin
        /home/ec2-user/.local/bin
        /home/ec2-user/bin
sys.path:

/home/ec2-user/anaconda3/envs/DS-CUSTOMER-DISCOVERY/bin

/home/ec2-user/anaconda3/envs/DS-CUSTOMER-DISCOVERY/lib/python37.zip

/home/ec2-user/anaconda3/envs/DS-CUSTOMER-DISCOVERY/lib/python3.7

/home/ec2-user/anaconda3/envs/DS-CUSTOMER-DISCOVERY/lib/python3.7/lib-dynload

/home/ec2-user/anaconda3/envs/DS-CUSTOMER-DISCOVERY/lib/python3.7/site-packages
sys.executable:

/home/ec2-user/anaconda3/envs/DS-CUSTOMER-DISCOVERY/bin/python3.7
sys.version:

3.7.3 | packaged by conda-forge | (default, Jul  1 2019, 21:52:21)

[GCC 7.3.0]
platform.platform():

Linux-4.14.158-101.185.amzn1.x86_64-x86_64-with-glibc2.10
which -a jupyter:

/home/ec2-user/anaconda3/envs/DS-CUSTOMER-DISCOVERY/bin/jupyter

/home/ec2-user/anaconda3/envs/DS-CUSTOMER-DISCOVERY/bin/jupyter

/home/ec2-user/anaconda3/bin/jupyter

/home/ec2-user/anaconda3/bin/jupyter

Command Line Output

Paste the output from your command line running `jupyter lab` here, use `--debug` if possible.

Browser Output

Paste the output from your browser Javascript console here.

[jasongrout]

Thanks for reporting this. That is very weird, and I don't remember ever hearing of something like this happening. The first thing I think of is that perhaps a browser extension or a jupyterlab extension is messing something up.

I realize since you can't reproduce it reliably, it's hard to try to narrow things down by going through the diagnosis guidelines at https://jupyterlab.readthedocs.io/en/stable/getting_started/issue.html. But at a very minimum, next time you see this, can you try disabling any browser extensions and jupyterlab extensions you may have installed?

[jasongrout]

Setting as "needs info" for a better way to reproduce this, and pending reproduction with no browser and jlab extensions installed. Also, were there any js console errors?

[lesliewalcott]

Hi Jason, if this happens again, I will comment here with more information. I don't have many Chrome extensions installed, but I have quite a few Jupyter extensions, so I will try disabling. No js console errors.

[jasongrout]

Note that you can start JupyterLab with only the stock builtin plugins (i.e., no custom plugins you've installed) with jupyter lab --core. It's sort of like the "safe mode" in operating systems.

[garima26]

The same is happening to me.

[jasongrout]

Can you go through the diagnosis guides linked above to try to narrow down what might be causing the issue, or to come up with instructions to reproduce this?

[jasongrout]

Closing as inactive. Please comment to continue the discussion.