XmlWriterSettings.NewLineChars defaults to "\n" on Linux, contrary to docs

[KalleOlaviNiemitalo]

Description

On Linux, the default value of XmlWriterSettings.NewLineChars is "\n", even though the documentation says it is "\r\n".

Reproduction Steps

PowerShell 7.2.5 using .NET 6.0.6 on Debian:

[System.Xml.XmlWriterSettings]::new().NewLineChars.GetEnumerator() | % { [int]$_ }

Expected behavior

Should output

13
10

Actual behavior

Outputs only

10

Regression?

I don't know

Known Workarounds

Assign XmlWriterSettings.NewLineChars after construction.

Configuration

.NET 6.0.6 on Debian 11.3 amd64.
The issue does not occur on Windows.

Other information

https://github.com/dotnet/runtime/blob/7cca709db2944a09b4db6ca7b20c457ff260fb5a/src/libraries/System.Private.Xml/src/System/Xml/Core/XmlWriterSettings.cs#L159-L160

https://github.com/dotnet/runtime/blob/7cca709db2944a09b4db6ca7b20c457ff260fb5a/src/libraries/System.Private.Xml/src/System/Xml/Core/XmlWriterSettings.cs#L723

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Issue Details

---

Description

On Linux, the default value of XmlWriterSettings.NewLineChars is "\n", even though the documentation says it is "\r\n".

Reproduction Steps

PowerShell 7.2.5 using .NET 6.0.6 on Debian:

[System.Xml.XmlWriterSettings]::new().NewLineChars.GetEnumerator() | % { [int]$_ }

Expected behavior

Should output

13
10

Actual behavior

Outputs only

10

Regression?

I don't know

Known Workarounds

Assign XmlWriterSettings.NewLineChars after construction.

Configuration

.NET 6.0.6 on Debian 11.3 amd64.
The issue does not occur on Windows.

Other information

https://github.com/dotnet/runtime/blob/7cca709db2944a09b4db6ca7b20c457ff260fb5a/src/libraries/System.Private.Xml/src/System/Xml/Core/XmlWriterSettings.cs#L159-L160

https://github.com/dotnet/runtime/blob/7cca709db2944a09b4db6ca7b20c457ff260fb5a/src/libraries/System.Private.Xml/src/System/Xml/Core/XmlWriterSettings.cs#L723

Author:	KalleOlaviNiemitalo
Assignees:	-
Labels:	area-System.Xml, untriaged
Milestone:	-

[krwq]

Unless there is strong justified objection IMO this is a doc bug.

[krwq]

@KalleOlaviNiemitalo if you're interested in contributing a fix click edit button on the documentation page. You might want to match description with https://docs.microsoft.com/en-us/dotnet/api/system.environment.newline?view=net-6.0 or just say we use that as the default

[krwq]

You might want to search for NewLineChars in the xml folder: https://github.com/dotnet/dotnet-api-docs/tree/main/xml/System.Xml - there seem to be more places which might need update (some other samples etc)