Task XslTransformation: How to specify XmlSpace.Preserve?

[NMertsch]

Issue Description

The MSBuild Task XslTransformation (docs, source) always loads the provided XSLT file with XmlSpace.Default. I would like to use XmlSpace.Preserve instead.

Steps to Reproduce

See this project. It contains an XSL stylesheet, an input XML file, and a dotnet project that generates two output files: one with the XslTransformation task, one in Program.cs. It also contains both output files so you can see the difference in GitHub.

You can clone the repo, delete the generated files, and run dotnet run to re-generate them.

Expected Behavior

Both files have the same content.

Actual Behavior

The MSBuild Task does not preserve whitespace and offers no way to change this behavior (at least none that I was able to find).

Analysis

The desired behavior can be achieved by changing new XPathDocument(reader) to new XPathDocument(reader, XmlSpace.Preserve) in this line.

I'm happy that XmlSpace.Default is the default. But I'd like to have an option to use XmlSpace.Preserve instead, e.g. via <XslTransformation PreserveWhitespace="true" ... />.

Versions & Configurations

To reproduce this, I use the dotnet CLI without IDE.

• dotnet --version: 6.0.300
• OS: Windows 10 Pro (Version 10.0.19044 Build 19044)

[rainersigwald]

Team triage: Nice analysis! We would accept a new argument to the task that passes a bool down to that call.

[shadyalfred]

Are the parameters specified in the .csproj file automatically mapped to the XslTransformation class? Because I couldn't find how they're read, except in the test files where the properties of XslTransformation are manually assigned. Am I correct in guessing that only adding a boolean property (which changes the behavior of XPathDocument) to XslTransformation is enough? However, adding a new property to the XslTransformation class gives an error

error RS0016: Symbol 'PreserveWhitespace.get' is not part of the declared API

Update: fixed it by modifying the public API files

[rainersigwald]

Are the parameters specified in the .csproj file automatically mapped to the XslTransformation class? Because I couldn't find how they're read, except in the test files where the properties of XslTransformation are manually assigned. Am I correct in guessing that only adding a boolean property (which changes the behavior of XPathDocument) to XslTransformation is enough?

That's correct; there is some documentation on task invocation and if you want the details you might be interested in TaskExecutionHost.SetTaskParameters.

However, adding a new property to the XslTransformation class gives an error

error RS0016: Symbol 'PreserveWhitespace.get' is not part of the declared API

Update: fixed it by modifying the public API files

That was almost perfect; I'm making a suggestion in your PR.