Avoid throwing when obsolete overload of GetUpdatesAsync is invoked with empty array

src/EditorFeatures/Core/EditAndContinue/EditAndContinueLanguageService.cs

@@ -312,7 +312,14 @@ public ValueTask<ManagedHotReloadUpdates> GetUpdatesAsync(CancellationToken canc
 
     [Obsolete]
     public ValueTask<ManagedHotReloadUpdates> GetUpdatesAsync(ImmutableArray<string> runningProjects, CancellationToken cancellationToken)
-        => throw new NotImplementedException();
+    {
+        // StreamJsonRpc may use this overload when the method is invoked with empty parameters. Call the new implementation instead.
+
+        if (!runningProjects.IsEmpty)
+            throw new NotImplementedException();
+
+        return GetUpdatesAsync(ImmutableArray<RunningProjectInfo>.Empty, cancellationToken);
+    }
 
     public async ValueTask<ManagedHotReloadUpdates> GetUpdatesAsync(ImmutableArray<RunningProjectInfo> runningProjects, CancellationToken cancellationToken)
     {

src/EditorFeatures/Core/EditAndContinue/EditAndContinueLanguageServiceBridge.cs

@@ -38,7 +38,14 @@ public ValueTask<ManagedHotReloadUpdates> GetUpdatesAsync(CancellationToken canc
 
     [Obsolete]
     public ValueTask<ManagedHotReloadUpdates> GetUpdatesAsync(ImmutableArray<string> runningProjects, CancellationToken cancellationToken)
-        => throw new NotImplementedException();
+    {
+        // StreamJsonRpc may use this overload when the method is invoked with empty parameters. Call the new implementation instead.
+
+        if (!runningProjects.IsEmpty)
+            throw new NotImplementedException();
+
+        return GetUpdatesAsync(ImmutableArray<RunningProjectInfo>.Empty, cancellationToken);
+    }
 
     public ValueTask<ManagedHotReloadUpdates> GetUpdatesAsync(ImmutableArray<RunningProjectInfo> runningProjects, CancellationToken cancellationToken)
         => service.GetUpdatesAsync(runningProjects, cancellationToken);

src/EditorFeatures/Test/EditAndContinue/EditAndContinueLanguageServiceTests.cs

@@ -319,6 +319,12 @@ await localWorkspace.ChangeSolutionAsync(localWorkspace.CurrentSolution
 
         Assert.True(sessionState.IsSessionActive);
 
+#pragma warning disable CS0612 // Type or member is obsolete
+        // validate that obsolete overload does not throw for empty array:
+        _ = await localService.GetUpdatesAsync(runningProjects: ImmutableArray<string>.Empty, CancellationToken.None);
+        Assert.Equal(++observedDiagnosticVersion, diagnosticRefresher.GlobalStateVersion);
+#pragma warning restore
+
         if (commitChanges)
         {
             // CommitUpdatesAsync