Huge output of 0's on >256 character to Convert.ToHexString()

[Hashbrown777]

Description

I'm hoping this works (you guys can repro) and isn't something wrong with PowerShell's calling of .NET.
I'm running Powershell 7.4 (with whatever .NET API that installs with).

Reproduction Steps

Expected behavior

Probably "Error: "Value was either too large or too small for an unsigned byte."" or 200F

Actual behavior

Regression?

No response

Known Workarounds

No response

Configuration

x64 Fedora Linux, I cannot ascertain the .NET version, google tells me to look up the non-existent registry value (please let me know if there's a way to ask the library itself at runtime, even if there might be a way to see via the installed files)

Other information

[colejohnson66]

Convert.ToHexString is documented as only allowing byte-like types. Specifically, byte[], byte[] with offset+length, and ReadOnlySpan<byte>. Trying to execute Convert.ToHexString('\u0100') or Convert.ToHexString('\u200F') fails to compile:

But if ran from PowerShell, it does indeed output a string of n zeros (where n is the character's value times two). I wonder if it's creating a byte array of length c and passing it into the method? An empty array of length n converted to a hexadecimal string is just n*2 zeros.

For example, [Convert]::ToHexString([char]0x200F).Length is 16414, and so is Convert.ToHexString(new byte[(uint)'\u200F']).Length:

This sounds like a PowerShell bug, not a .NET one.

[huoyaoyuan]

You can use [Environment]::Version to display underlying runtime version in PowerShell.

This sounds like a PowerShell bug, not a .NET one.

It may be an un-intuitive behavior of implicit dynamic casting.

[colejohnson66]

I tested on .NET 8.0.4 through PowerShell 7.4.2. If ran on the old non-Core PowerShell 5.1, it uses .NET Framework 4.0, so Convert.ToHexString doesn't exist (it was added in 5).

While it could be argued to be implicit casting behavior, I'd argue that it's a bug to implicitly cast an integer to an array of that length. But that's for PowerShell's repo to decide, not here.

[am11]

The issue is with the char[] cast.
[Convert]::ToHexString([char]"`u{200F}") should be:
[Convert]::ToHexString([System.Text.Encoding]::Unicode.GetBytes("`u{200F}"))

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[Hashbrown777]

Anyway to port issues across or do I close and open a new one over at PowerShell?

Edit: nvm, @colejohnson66 has done it. I guess I'll close this one if Michael considers it a pwsh issue on that ticket?

[Hashbrown777]

The issue is with the char[] cast.

Yeah I know how to do it properly once I saw the error, it's just that the error I saw wasn't an exception/message, it was some bad behaviour, so I thought I'd report it.

[Hashbrown777]

explained as happening prior to .NET receiving the arguments