Fix command history while debugging

[SeeminglyScience]

This change fixes command history while debugging.

• Fixed internal commands being added to command history.
• Fixed ConsoleReadLine not retrieving history correctly.

[daviwil]

Thanks so much for trying to fix this one! One thing I realized about using 'prompt' to suppress history, if the user has a custom prompt function that writes output directly to the console (Write-Host, etc), this approach might cause unwanted output to be written to the console. Can you try that and see if it's a problem?

[daviwil]

Maybe if PSReadline support makes this unnecessary we can skip it, though it might be useful for cases where PSES is used without support for the terminal PSHost implementation.

[SeeminglyScience]

I'm torn about what to do with this. PSReadLine does solve this for the most part, but it still shows up in Get-History and it still increments the HistoryId. The latter is really annoying when using a customized prompt like PowerLine.

Write-Host won't bleed through on PSv3 or PSv5+. It doesn't on 3 because the fix doesn't apply, there is no Debugger.ProcessCommand. All debugger commands just go through nested pipelines which have a built in way to disable history. It doesn't on 5 because Write-Host writes to the information stream, which we redirect into output.

I haven't tested on 4, but I suspect that is where it would be an issue as it has ProcessCommand and does not have the information stream.

For those interested, this fix depends on undocumented logic in the debugger to disable history if the command is member of a specific set of commands. The commands are prompt, TabExpansion2, Set-PSDebuggerAction, Get-PSDebuggerStopArgs, and Set-PSDebugMode. prompt has the issues already discussed, and I discounted TabExpansion2 because is slow and potentially heavily customized. The last three I assume are used in workflow debugging, but I can't actually find any reference to them anywhere.

The way I see it there's a couple options:

1. Create a empty function in the Commands module with the name of one of the last three commands

2. Since any of these potential fixes depend on undocumented behavior, I could dig into reflection to see if there is anything we can do more directly for just PSv4

3. Don't fix history for PSv4, only fix PSv3 and PSv5+

4. Just use prompt as the fix across the board and acknowledge Write-Host as causing issues with debugging in PSv4

[TylerLeonhardt]

@SeeminglyScience can we close this since it's addressed in your PSRL PR?

[SeeminglyScience]

@tylerl0706 Yeah I'll close it, but it's not 100% addressed. Functionally it is, but there's still some strange side effects like Get-History showing background commands and $MyInvocation.HistoryId still increments.

Either way this PR is way too old, new changes would have to be in a new PR anyway.