DivideByZeroException when running Docker container from mcr.microsoft.com/powershell:latest

[reed9999]

I presently don't have enough PowerShell or Docker expertise to intuit whether this is important. I don't see any obvious duplicates (#670 might be related).

The logs included the following, which seems to the same as output produced by the scripts in this template.

Oops, something went wrong.

Please report this bug with ALL the details below, including both the 'Environment' and 'Exception' sections.

Please report on GitHub: https://github.com/PowerShell/PSReadLine/issues/new?template=Bug_Report.md

Thank you!


### Environment

PSReadLine: 2.1.0
PowerShell: 7.1.4
OS: Linux 5.10.16.3-microsoft-standard-WSL2 #1 SMP Fri Apr 2 22:23:49 UTC 2021
BufferWidth: 0
BufferHeight: 0

Last 200 Keys

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### Exception

System.DivideByZeroException: Attempted to divide by zero.

   at Microsoft.PowerShell.PSConsoleReadLine.PhysicalLineCount(Int32 columns, Boolean isFirstLogicalLine, Int32& lenLastPhysicalLine)

   at Microsoft.PowerShell.PSConsoleReadLine.ReallyRender(RenderData renderData, String defaultColor)

   at Microsoft.PowerShell.PSConsoleReadLine.ForceRender()

   at Microsoft.PowerShell.PSConsoleReadLine.BackwardDeleteChar(Nullable`1 key, Object arg)

   at Microsoft.PowerShell.PSConsoleReadLine.ProcessOneKey(PSKeyInfo key, Dictionary`2 dispatchTable, Boolean ignoreIfNoAction, Object arg)

   at Microsoft.PowerShell.PSConsoleReadLine.InputLoop()

   at Microsoft.PowerShell.PSConsoleReadLine.ReadLine(Runspace runspace, EngineIntrinsics engineIntrinsics, CancellationToken cancellationToken)

(I removed the triple-backticks so I could use triple backticks here. I also manually deleted some empty lines to make it single spaced; apparently that's a copy/paste issue from my shell.)

Environment

I managed to run the script given here in the CLI for my container; it produced the following, which I think just repeats what's above:

PS version: 7.1.4
PSReadline version: 2.1.0
os: Linux ee4a2cd279b6 5.10.16.3-microsoft-standard-WSL2 #1 SMP Fri Apr 2 22:23:49 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
PS file version: 7.1.4.0
HostName: ConsoleHost
BufferWidth: 120
BufferHeight: 30

Exception report

See above (?)

Steps to reproduce

• A few days ago, I downloaded the mcr.microsoft.com/powershell Docker image to my three-month-old Windows 10 personal laptop. 6eee80913d43 is the image ID.
• Used it to start a container, but because Docker Dashboard didn't update, I didn't realize the container was running.
• In Docker Dashboard, I found the container running and checked the logs, which included the following:

Expected behavior

Presumably it's expected to work, in which case the log would not tell me to submit an issue on Github.

Actual behavior

The logs asked me to file an issue and gave me the text above to include here.

[daxian-dbw]

The environment data shows both BufferWidth and BufferHeight are 0, and obviously that resulted in the DivideByZeroException. I wonder why that would happen. @TravisEz13 can you please share your insight?

[daxian-dbw]

@reed9999 What was the command you used to start the container?

[daxian-dbw]

My investigation shows that the DivideByZeroException exception is caused by having the container detached.
When a container is detached, System.Console.BufferWidth and System.Console.BufferHeight are both 0, meaning the console windows doesn't exist, and it's actually a broken state. That leads to the DivideByZeroException.

In your case, you didn't know the container was running, and that's very likely it's running in detached mode, and thus explains why BufferWidth and BufferHeight are both 0.

I don't think there is anything to fix in PSReadLine. As a workaround, if you need to start the container in a detached mode, then instead of using the default CMD, which is really just for interactive attached usage, just explicitly specify a command to prevent things to shutdown, such as

docker run --name=mypowershell -itd mcr.microsoft.com/powershell:latest pwsh -c "[console]::ReadKey()"

Then, you can run docker exec -it mypowershell /bin/bash or docker exec -it mypowershell pwsh

This issue has been marked as answered and has not had any activity for 1 day. It has been closed for housekeeping purposes.