C#: Turn reachable fallback feeds into a property.

Author: michaelnebel

csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/FeedManager.cs

@@ -78,6 +78,13 @@ internal sealed partial class FeedManager : IDisposable
         /// </summary>
         public ImmutableHashSet<string> ReachableFeeds => lazyReachableFeeds.Value;
 
+        private readonly Lazy<ImmutableHashSet<string>> lazyReachableFallbackFeeds;
+        /// <summary>
+        /// Gets the list of reachable NuGet feeds that are configured as fallback feeds.
+        /// </summary>
+        public ImmutableHashSet<string> ReachableFallbackFeeds => lazyReachableFallbackFeeds.Value;
+
+
         public FeedManager(ILogger logger, IDotNet dotnet, DependabotProxy? dependabotProxy, FileProvider fileProvider)
         {
             this.logger = logger;
@@ -101,6 +108,11 @@ public FeedManager(ILogger logger, IDotNet dotnet, DependabotProxy? dependabotPr
                 CheckSpecifiedFeeds(InheritedFeeds, out var reachableInheritedFeeds);
                 return ReachableExplicitFeeds.Union(reachableInheritedFeeds).ToImmutableHashSet();
             });
+            lazyReachableFallbackFeeds = new Lazy<ImmutableHashSet<string>>(() =>
+            {
+                var reachableFallbackFeeds = GetReachableFallbackNugetFeeds();
+                return reachableFallbackFeeds.ToImmutableHashSet();
+            });
         }
 
 

csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/NugetPackageRestorer.cs

@@ -307,7 +307,7 @@ private void RestoreProjects(IEnumerable<string> projects, out ConcurrentBag<Dep
             if (feedManager.CheckNugetFeedResponsiveness || feedManager.HasPrivateRegistryFeeds)
             {
                 // Attempt to get the fallback configuration.
-                var reachableFallbackFeeds = feedManager.GetReachableFallbackNugetFeeds();
+                var reachableFallbackFeeds = feedManager.ReachableFallbackFeeds;
                 compilationInfoContainer.CompilationInfos.Add(("Reachable fallback NuGet feed count", reachableFallbackFeeds.Count.ToString()));
 
                 if (reachableFallbackFeeds.Count == 0)