MINOR: Environment Variable in CMD Prompt not resolved.

[FDFessler]

This is VERY MINOR: Environment Variable in CMD Prompt not resolved.

Environment

Windows build number: [run `[Environment]::OSVersion` for powershell, or `ver` for cmd]
Microsoft Windows [Version 10.0.19041.572]
Windows Terminal version (if applicable):
Windows Terminal Preview
Version: 1.4.2652.0
Settings for Command Prompt:
                // Make changes here to the cmd.exe profile.
                "guid": "{0caa0dad-35be-5f56-a8ff-afceeeaa6101}",
                "name": "Command Prompt",
                "commandline": "cmd.exe",
                "startingDirectory": "P:\\",
                "hidden": false

Any other software?

Steps to reproduce

Launch Command Prompt in WT

Expected behavior

While I have a fairly long (and "crazy") prompt string in my environment settings it seems to do everything right except resolve an environment name (in this case my PC name %ComputerName%).
Current Prompt:
$E[1;33;45m[$D--$T$H$H$H$H$H$H]$S$E[7;33;44m$C$N:$Q$M$H$F$$E[0;34;47m$P$E[0;37;44m$[%ComputerName%]:$S$+$G$S
Prompt should look like this:
[10/29/2020-- 9:38] (P:=\ServerName\Dir1\Dir2)
P:
[MyActualPCName]: >

Actual behavior

I get this (with all the correct colors) but the %ComputerName% is not resolved.
[10/29/2020-- 9:32] (P:=\ServerName\Dir1\Dir2)
P:
[%ComputerName%]: >

[zadjii-msft]

So here's the weird thing with the PROMPT command - environment variables in it are only expanded when the command is run, not when the prompt is displayed. So when you do:

PROMPT %COMPUTERNAME%$g

cmd evaluates %COMPUTERNAME% to whatever (in my case, MIGRIE-SLAPTOP, then sets the prompt to MIGRIE-SLAPTOP$g

So I'm betting that your prompt variable literally has %ComputerName% in it, rather than the evaluated value of %ComputerName%, right?

[FDFessler]

That is correct and is what I posted above.
It works if I just open a "normal" CMD prompt however. So, I'm OK if this is a limitation, just wanted to make sure this was not an "oversite".
You can duplicate the problem very easily by setting your Prompt environment string to just %ComputerName%$g
... and then seeing the difference between standard CMD prompt and WT CMD prompt.

[DHowett]

This is likely a side effect of us giving CMD a new environment block. I swear sometimes, this OS is too fragile to write code for.

[FDFessler]

This NOT a big deal (very minor IMO), I can just run my prompt manually after opening the COMMAND Prompt windows in WT. Like I said earlier, just wanted to make sure this was not an "oversite".
Thanks.

[LuanVSO]

this works for me

don't know why though ¯\_(ツ)_/¯

[DHowett]

Alright, after sitting on this issue for a while I've come to a conclusion.

This is technically the same as #7418, but for a different reason. The solution to both is the same, however: we have to do a 3-way merge and expand the environment block in Terminal before we start the next process.

Thanks 😄

/dup #7418

[ghost]

Hi! We've identified this issue as a duplicate of another one that already exists on this Issue Tracker. This specific instance is being closed in favor of tracking the concern over on the referenced thread. Thanks for your report!