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Range operator (aka DotDot operator) with char operands in pipeline throws error #5519

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TimCurwick opened this issue Nov 21, 2017 · 8 comments
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@TimCurwick
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@TimCurwick TimCurwick commented Nov 21, 2017

Steps to reproduce

A'..'B'
'A'..'B' | ForEach-Object { $_ }

Expected behavior

A
B

Actual behavior

Cannot convert value "A" to type "System.Int32". Error: "Input string was not in a correct format."
At line:1 char:1

  • 'A'..'B' | ForEach-Object { $_ }
  • CategoryInfo : InvalidArgument: (:) [], RuntimeException
  • FullyQualifiedErrorId : InvalidCastFromStringToInteger```

Environment data

----                           -----
PSVersion                      6.0.0-rc
PSEdition                      Core
GitCommitId                    v6.0.0-rc
OS                             Microsoft Windows 10.0.15063
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0```
@markekraus
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@markekraus markekraus commented Nov 21, 2017

repros for me.

@mklement0
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@mklement0 mklement0 commented Nov 21, 2017

Interesting; I didn't even know support for character ranges was implemented. Can I suggest changing "dotdot operator" to "range operator" in the title?

@TimCurwick
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@TimCurwick TimCurwick commented Nov 21, 2017

I went with "dotdot operator" because that is what was used in the PR that added the character range implementation. #5026

@mklement0
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@mklement0 mklement0 commented Nov 21, 2017

I see - that very nonstandard name is the reason that I wasn't able to find this new feature, despite then already knowing that it exists (based on this issue - that someone else would call it "DotDot operator" too hadn't occurred me), so thank you for adding the link.

I guess my mentioning the construct's official name here - range operator - now makes this issue more discoverable and, by extension, now also the linked PR, but my preference is always to have the important keywords in the title, as an in:title search then allows for a more focused search.

@mklement0
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@mklement0 mklement0 commented Nov 21, 2017

Another datapoint (and workaround): Forcing generation of the entire array up front avoids the problem:

('A'..'B') | ForEach-Object { $_ }  # OK, due to (...)
@IISResetMe
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@IISResetMe IISResetMe commented Nov 21, 2017

The output from Trace-Command strongly suggests that this code path is reached before the operator is explicitly invoked when the .. appears as the very first operation in a pipeline:

PS C:\> Trace-Command -Expression {'A'..'B' |ForEach-Object { $_ }} -Name * -Option All -FilePath ($t = [System.IO.Path]::GetTempFileName()) 2>$null; Get-Content $t -TotalCount 2
TypeConversion Information: 0 : Converting to integer.
TypeConversion Information: 0 : Exception converting to integer: "Input string was not in a correct format.".

Why, I'm not entirely certain yet, will keep digging. While this is certainly not the intended behavior of the new [char] overload for .., it doesn't seem to break any previously defined behavior (this is basically the expected behavior for $string..$otherstring prior to #5026)

Re: the "nonstandard" name, I took it from the token that represents the underlying range operator :-)

@SteveL-MSFT SteveL-MSFT changed the title DotDot operator with char operands in pipeline throws error Range operator (aka DotDot operator) with char operands in pipeline throws error Nov 21, 2017
@mklement0
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@mklement0 mklement0 commented Nov 22, 2017

@SteveL-MSFT: Your title edit just made my day, thanks (I wish I were kidding).

@IISResetMe: Fair enough, and perhaps "DotDot operator" is reasonably well-known; my term for it came from Get-Help about_Operators, and I would argue that it's the more sensible name:

Operators should be named for their purpose (only), not their syntactic form (too).

I won't repeat my rant about about the "dot sourcing operator" here.
Although, who's to say? Perhaps it's time for the "asterisk multiplication operator", or the "hyphen-minus subtraction operator", and, last but not least, the "dot-dot range operator".

@lzybkr
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@lzybkr lzybkr commented Nov 22, 2017

@IISResetMe - the idea was to name tokens after the syntactic form because it might not make sense if a token was allowed in some new context, e.g. if .. was allowed where it is no longer the range operator.

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