Fix cross project span and edit mapping

[davidwengier]

Fixes #12608

Previous code was making bad assumptions about everything being in one project, and just using hint name to identify a generated document. New code uses SourceGeneratedDocumentIdentity, which can reason about projects, and hides direct hint name use as much as possible.

[ToddGrun]

AddProjectAndRazorDocument

aside: seems odd this method would need to take in a projectid and documentid and not just generate them itself. Or is this method potentially called on existing projectid/documentids?

[davidwengier]

Yes, to simulate OOP syncing in tests we create two solutions with identical projects and documents, but different MEF compositions, so the IDs have to match.

[ToddGrun]

TryGetSourceGeneratedDocument

Dumb question:

Could this just return the SourceGeneratedDocument directly, instead of having the callers understand the identity stuff?

[davidwengier]

AFAIK getting the source generated document would mean running the source generators, this can get the identity without doing that. Also, getting the source generated document is only useful if that's what you need to work with. To get the originating Razor document for a source generated document, you'd need to go back to the identity anyway.

[ToddGrun]

Just to clarify, I was thinking along something like:

public static async Task<SourceGeneratedDocument?> TryGetSourceGeneratedDocumentAsync(this Solution solution, Uri generatedDocumentUri, CancellationToken cancellationToken)
{
    if (!RazorUri.IsGeneratedDocumentUri(generatedDocumentUri) ||
        !solution.TryGetSourceGeneratedDocumentIdentity(generatedDocumentUri, out var identity) ||
        !solution.TryGetProject(identity.DocumentId.ProjectId, out var project))
    {
        return null;
    }

    return await project.TryGetCSharpDocumentForGeneratedDocumentAsync(identity, cancellationToken).ConfigureAwait(false);
}

in SolutionExtensions.cs and something like:

public async Task<RazorCodeDocument?> TryGetSourceGeneratedDocumentAsync(Solution solution, Uri generatedDocumentUri, CancellationToken cancellationToken)
{
    if (!RazorUri.IsGeneratedDocumentUri(generatedDocumentUri) ||
        !solution.TryGetSourceGeneratedDocumentIdentity(generatedDocumentUri, out var identity) ||
        !identity.IsRazorSourceGeneratedDocument() ||
        !solution.TryGetProject(identity.DocumentId.ProjectId, out var project))
    {
        return null;
    }

    return await GetSnapshot(project).TryGetCodeDocumentForGeneratedDocumentAsync(identity, cancellationToken).ConfigureAwait(false);
}

in RemoteSnapshotManager.cs. But maybe that still has the issues that you called out?

[davidwengier]

ohhh, I see what you're saying, helper methods for the common scenarios. Yes, that would work. This method might still need to stay too, but I should be able to simplify some of the calling code. Will take a look

[davidwengier]

Logged #12637 to follow up, probably post-snap

[ToddGrun]