VisibilityContraint for the Diff Service / Editor?

[CalvinAllen]

Is there any way to toggle the visibility of a button / right-click context menu item (defined in the VSCT file) to be visible in the "standard" code editor, but not the "diff" view editor/window?

I was thinking this might be possible with VisibilityContraints, but I can't seem to find enough info on 'context' to be certain. If that isn't possible, any other ideas?

Thanks

[reduckted]

I added this code to work out what contexts become active while the diff editor is open:

protected override async Task InitializeAsync(CancellationToken cancellationToken, IProgress<ServiceProgressData> progress) {
    await JoinableTaskFactory.SwitchToMainThreadAsync(cancellationToken);
    IVsUIContextMonitor monitor = await VS.GetServiceAsync<SVsUIContextMonitor, IVsUIContextMonitor>();
    monitor.AdviseContextEvents(this); // "this" is my package, which implements IVsUIContextEvents.
}

public void OnContextChanged(Guid uiContext, bool active) {
    System.Diagnostics.Debug.WriteLine(uiContext.ToString() + " : " + active);
}

From the results, it looks like the GUID for the diff editor is {282DEB30-FC73-43D9-A9E9-41F1F6D33F30}.

I added this to the .vsct file:

<VisibilityConstraints>
    <VisibilityItem guid="TestExtension" id="MyCommand" context="CodeButNotDiffContext" />
</VisibilityConstraints>

<Symbols>
    <GuidSymbol name="CodeButNotDiffContext" value="{9254612C-DC95-43F3-B310-82320EC34775}" /> <!-- The GUID is unimportant here - it just needs to match the GUID in the `ProvideUIContextRule` attribute). -->
</Symbols>

I couldn't get the visibility to work for all "standard code editors", but this worked for most of them. It wasn't active for XML-like files (.xml, .props, etc), but that might not be a problem for you):

[ProvideUIContextRule("{9254612C-DC95-43F3-B310-82320EC34775}",
    name: "CustomContext",
    expression: "TextEditor & !DiffEditor",
    termNames: new[] { "TextEditor", "DiffEditor" },
    termValues: new[] { VsEditorFactoryGuid.TextEditor_string, "{282DEB30-FC73-43D9-A9E9-41F1F6D33F30}" }
)]

Another approach that seemed to work was to be active when a document window is open, but not when a property page designer is open (because they are also "document windows"):

[ProvideUIContextRule("{9254612C-DC95-43F3-B310-82320EC34775}",
    name: "CodeButNotDiffContext",
    expression: "DocumentWindowActive & !PropertyPageDesigner & !DiffEditor",
    termNames: new[] { "DocumentWindowActive", "PropertyPageDesigner", "DiffEditor" },
    termValues: new[] { UICONTEXT.DocumentWindowActive_string, UICONTEXT.PropertyPageDesigner_string, "{282DEB30-FC73-43D9-A9E9-41F1F6D33F30}" }
)]

[ProvideUIContextRule("{9254612C-DC95-43F3-B310-82320EC34775}",
    name: "CodeButNotDiffContext",
    expression: "IsDocument & (!DiffEditor)",
    termNames: new[] { "IsDocument", "DiffEditor" },
    termValues: new[] { VSConstants.UICONTEXT.DocumentWindowActive_string, "{282DEB30-FC73-43D9-A9E9-41F1F6D33F30}" }
)]

It's also worth noting that using "ActiveEditorContentType:diff" instead of the diff editor's GUID worked, but for some reason "ActiveEditorContentType:code" didn't work. Maybe I had something else wrong, but here's what I tried:

[ProvideUIContextRule("{9254612C-DC95-43F3-B310-82320EC34775}",
    name: "CodeButNotDiffContext",
    expression: "IsCode & !IsDiff",
    termNames: new[] { "IsCode", "IsDiff" },
    termValues: new[] { "ActiveEditorContentType:code", "ActiveEditorContentType:diff" }
    // "ActiveEditorContentType:code" doesn't seem to work :(
)]

[CalvinAllen]

Epic reply, @reduckted! I will need to look into all of this more deeply (peruse the docs, etc.), as its beyond anything I've worked with before. Thanks!