Fix broken analyzer child nodes in Solution Explorer

In 17.2, CPS made a change to how paths are used for non-file items in the tree. These changes improve the performance of searching the dependency tree by path, as the pseudo-id used for items not having paths allows a fast lookup.

That change broke the ability for Roslyn to determine the correct file path for analyzer nodes (via CanonicalName), which then broke the ability to attach child nodes to the analyzer in Solution Explorer (for example, to show source generators and the files they create).

In this commit, we add the FileSystemEntity flag to analyzer nodes. This causes CPS to preserve the full path provided on the IProjectTree, which restores the CanonicalName for Roslyn.

src/Microsoft.VisualStudio.ProjectSystem.Managed/ProjectSystem/Tree/Dependencies/Models/AnalyzerDependencyModel.cs

@@ -8,9 +8,15 @@ namespace Microsoft.VisualStudio.ProjectSystem.Tree.Dependencies.Models
 {
     internal class AnalyzerDependencyModel : DependencyModel
     {
+        // NOTE we include ProjectTreeFlags.FileSystemEntity here so that Roslyn can
+        // correctly identify the analyzer's path in order to attach child nodes to
+        // these dependency items in Solution Explorer. Without this flag, CPS will
+        // remove whatever file path we pass during tree construction (for performance
+        // reasons).
+
         private static readonly DependencyFlagCache s_flagCache = new(
-            resolved: DependencyTreeFlags.AnalyzerDependency + DependencyTreeFlags.SupportsBrowse,
-            unresolved: DependencyTreeFlags.AnalyzerDependency + DependencyTreeFlags.SupportsBrowse);
+            resolved: DependencyTreeFlags.AnalyzerDependency + DependencyTreeFlags.SupportsBrowse + ProjectTreeFlags.FileSystemEntity,
+            unresolved: DependencyTreeFlags.AnalyzerDependency + DependencyTreeFlags.SupportsBrowse + ProjectTreeFlags.FileSystemEntity);
 
         private static readonly DependencyIconSet s_iconSet = new(
             icon: KnownMonikers.CodeInformation,

tests/Microsoft.VisualStudio.ProjectSystem.Managed.UnitTests/ProjectSystem/Tree/Dependencies/Models/AnalyzerDependencyModelTests.cs

@@ -37,7 +37,8 @@ public void Resolved()
             Assert.Equal(
                 DependencyTreeFlags.AnalyzerDependency +
                 DependencyTreeFlags.SupportsBrowse +
-                DependencyTreeFlags.ResolvedDependencyFlags,
+                DependencyTreeFlags.ResolvedDependencyFlags +
+                ProjectTreeFlags.FileSystemEntity,
                 model.Flags);
         }
 
@@ -69,7 +70,8 @@ public void Unresolved()
             Assert.Equal(
                 DependencyTreeFlags.AnalyzerDependency +
                 DependencyTreeFlags.SupportsBrowse +
-                DependencyTreeFlags.UnresolvedDependencyFlags,
+                DependencyTreeFlags.UnresolvedDependencyFlags +
+                ProjectTreeFlags.FileSystemEntity,
                 model.Flags);
         }
 
@@ -102,7 +104,8 @@ public void Implicit()
                 DependencyTreeFlags.AnalyzerDependency +
                 DependencyTreeFlags.SupportsBrowse + 
                 DependencyTreeFlags.ResolvedDependencyFlags -
-                DependencyTreeFlags.SupportsRemove,
+                DependencyTreeFlags.SupportsRemove +
+                ProjectTreeFlags.FileSystemEntity,
                 model.Flags);
         }
     }