TextDocument.Folders is always empty for additional files

[etvorun]

Version Used: 4.300.22.22804

Steps to Reproduce:

1. Unzip attached file.
2. Open MauiApp4\MauiApp4.sln
3. Use Solution Explorer to open (and debug Roslyn internals) MyControl.xaml, LinkedControl.xaml and dark.xaml from SharedMaui project.
   MauiRepro.zip

Expected Behavior: TextDocument.Folders contains folders matching folder structure in solution explorer

Actual Behavior: TextDocument.Folders always contains 0 items

Note: *.cs files have valid Folders for plain and linked items; empty for *.cs files from SharedMaui project.

[etvorun]

This is related to #44131. Most likely due to the fact that IWorkspaceProjectContext.AddAdditionalFile does not accept folders (unlike IWorkspaceProjectContext.AddSourceFile).

XAML intellisense needs to know project relative paths. For example, in order to display completion for <Button Background='...' it needs to walk merged resource dictionaries like <ResourceDictionary Source='views/resources/Styles.xaml'> or <ResourceDictionary Source='/MyLib;component/controls/colors.xaml'>. Thus we need to do two things:

• [optional]: find Project for MyLib
• find additional document based on project relative path \controls\colors.xaml. Actual document can be a linked file or come from shared project

[etvorun]

@jasonmalinowski can you please take a look :)

[jasonmalinowski]

I think this recently came up too in the replacement for IWorkspaceProjectContext that we were working on with @tmeschter -- we weren't doing link file support (or something equivalent) for additional files since we didn't really have any idea somebody would have a need for them.

That said, I'm still confused on the scenario here @etvorun -- the existing XAML compiler also consumes link directives to handle things like this at the MSBuild layer? Because Roslyn doesn't use these folders other than when doing a few refactorings and placing new files on disk. It's not something we use to impact our semantics at all.

[ghost]

Closing this issue as we've seen no reply to the request for more information. If you are able to get the requested information, please add it to the issue and we will retriage it.

[etvorun]

@jasonmalinowski
Example:
/Views/MyPage.xaml

<Page>
  <Page.Resources>
    <ResourceDictonary>
      <ResourceDictonary.MergedDictionaries>
        <ResourceDictonary Source='Styles.xaml'/> <!-- relative to document -->
        <ResourceDictonary Source='/Styles.xaml'>  <!-- relative to project root -->
        <ResourceDictonary Source='/Resources/Styles.xaml'>  <!-- relative to project root -->
        <ResourceDictonary Source='/MyLib;component/Resources/Styles.xaml'>  <!-- relative to referenced project which builds MyLib.dll -->
      </ResourceDictonary.MergedDictionaries>
    </ResourceDictonary>
  </Page.Resources>
  <Button Style='{StaticResource }'/>
<Page>

To show intellisense when editing {StaticResource } we need to examine content of *.xaml files listed in MergedDictionaries sections. That requires finding AdditionalDocument based on project relative path, i.e. it is a function of TextDocument.Folders + TextDocument.Name. If TextDocument.Folders are always empty then it would break XAML intellisense.

[dibarbet]

@arkalyanms for scheduling - XAML needs this for their LSP implementation