Breakpoints error when using Select-ObjectIndex

[ninmonkey]

About

• Select-ObjectIndex sometimes breaks $error
• when it does, referencing that index will print nothing in the term
• empty ones also create multiple new ErrorRecords every prompt

Possible Causes

• a stale/corrupt debug environment
• Probably not a design issue -- otherwise why is it working in the same context
• Maybe scope related -- like referencing $local:error vs $global:error (Debugging inside and outside modules cope issues)
• Is $errors a ring buffer? It wraps after index 255. Could overflowing past index 255, end up invalidating a previous reference to $error[0] ? Or would it copy the original on write?

Because when debugging things, you can easily wrap 255.

To Reproduce

In my testing, it felt like it was split, either: 100% it would reproduce, or 0%

• Be in a breakpoint
• Create some errors, then index it:
• It felt like hitting 0 before 3 was more likely -- so maybe there's a reference in there?

$Error.count  # returns 130 # existing errors
$Error | Utility\Select-ObjectIndex 0
      # <the first time you get the right error>

$Error | Utility\Select-ObjectIndex 3        # errors don't print
$Error | Utility\Select-ObjectIndex 0        # errors don't print

> Collection was modified, cannot enumerate. 

Once it starts, you can only reference the error in some ways. So when debugging it -- make sure your prompt has $error.count in it. In the screenshot, Select-Object adds 3 errors, every time ( Maybe it hints to the uncaught error being fired inside the formatter? )

# 169！7.2.6
Pwsh> $error | Select-Object -First 3

# 172！7.2.6
Pwsh> $error | select -First 10

#175！7.2.6
Pwsh> $error | select -First 10

[ninmonkey]

Possibly related, I noticed that they end up copying by value, not ref, $serr = $error does not.

$serr = $error
$serr2 = $error | select -first 3
$serr3 = $error[0..2]

At least in this case, $serr2, $serr3's version did not increase in count, but $serr does.

$serr2.count; $serr.count; $serr3.Count ;1 /0; $serr2.count; $serr.count; $serr3.Count