CODEWITHSUNDEEP
powershelldebugging
Frode F.
Frode F.

Reputation: 54881

Trace/debug PowerShell operators

In PowerShell I can use Trace-Command to troubleshoot parameter binding, type conversion etc. Ex:

Trace-Command -PSHost -Name ParameterBinding -Expression { $null = "c:\" | dir}
...
DEBUG: ParameterBinding Information: 0 :     Parameter [Path] PIPELINE INPUT ValueFromPipeline NO COERCION
DEBUG: ParameterBinding Information: 0 :     BIND arg [c:\] to parameter [Path]
DEBUG: ParameterBinding Information: 0 :         Binding collection parameter Path: argument type [String], parameter type [System.String[]], collection type Array, eleme
nt type [System.String], no coerceElementType
...

While debugging some strange behavious in PS I wanted to trace how -lt comparison works (maybe it converts to [int][char]"x" for each character etc.). I tried to use Trace-Command but it doesn't return anything.

Trace-Command -PSHost -Name TypeMatch, TypeConversion -Expression { "Less" -lt "less" }
#No trace-output, only returned value
False

#Get any type of trace-informatino
Trace-Command -PSHost -Name * -Expression { "Less" -lt "less" }
#No trace-output, only returned value
False

Is there any way to find out how these internal operators work behind-the-scenes? Trace information? Verbose output? I've used -lt and -gt as an example, but this could just as well have been the &-operator and how it parses the command or something else.

Upvotes: 2

Views: 428

Answers (1)

JPBlanc
JPBlanc

Reputation: 72630

Not sure it helps but -lt and -gt are case un-sensitive operators they behaves like -ilt and -igt. If you want case sensitive operators you should use -clt and -cgt.

Here is the result I obtain in PowerShell 5.0, I'am not sure it helps

Trace-Command -PSHost -Name TypeMatch, TypeConversion -Expression { "Less" -lt "less" }
DÉBOGUER : TypeConversion Information: 0 : Converting "System.Object[]" to "System.Object".
DÉBOGUER : TypeConversion Information: 0 :     Result type is assignable from value to convert's type
DÉBOGUER : TypeConversion Information: 0 : Converting "" to "System.String".
DÉBOGUER : TypeConversion Information: 0 :     Result type is assignable from value to convert's type
DÉBOGUER : TypeConversion Information: 0 : Converting "" to "System.String".
DÉBOGUER : TypeConversion Information: 0 :     Result type is assignable from value to convert's type
DÉBOGUER : TypeConversion Information: 0 : Converting "System.Management.Automation.InvocationInfo" to "System.Management.Automation.InvocationInfo".
DÉBOGUER : TypeConversion Information: 0 :     Result type is assignable from value to convert's type
DÉBOGUER : TypeConversion Information: 0 : Converting "System.Object[]" to "System.Object[]".
DÉBOGUER : TypeConversion Information: 0 :     Result type is assignable from value to convert's type
False

I obtain the same trace if I use -cgt but the result is True.

Upvotes: 1

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