fixed where project name gets disappeared if a project is unloaded in "BuildOnly" error list mode.

now we will show <Unknown> for such project.

src/VisualStudio/Core/Def/Implementation/TableDataSource/AbstractTableDataSource.cs

@@ -47,6 +47,29 @@ public AbstractTableDataSource(Workspace workspace)
 
         public abstract string Identifier { get; }
 
+        public void RefreshAllFactories()
+        {
+            ImmutableArray<SubscriptionWithoutLock> snapshot;
+            List<TableEntriesFactory<TData>> factories;
+
+            lock (_gate)
+            {
+                snapshot = _subscriptions;
+                factories = _map.Values.ToList();
+            }
+
+            // let table manager know that we want to refresh factories.
+            for (var i = 0; i < snapshot.Length; i++)
+            {
+                foreach (var factory in factories)
+                {
+                    factory.OnRefreshed();
+
+                    snapshot[i].AddOrUpdate(factory, newFactory: false);
+                }
+            }
+        }
+
         public void Refresh(TableEntriesFactory<TData> factory)
         {
             var snapshot = _subscriptions;
@@ -59,6 +82,11 @@ public void Refresh(TableEntriesFactory<TData> factory)
 
         public void Shutdown()
         {
+            // editor team wants us to update snapshot versions before
+            // removing factories on shutdown.
+            RefreshAllFactories();
+
+            // and then remove all factories.
             ImmutableArray<SubscriptionWithoutLock> snapshot;
 
             lock (_gate)
@@ -214,29 +242,6 @@ protected void ChangeStableState(bool stable)
             }
         }
 
-        protected void RefreshAllFactories()
-        {
-            ImmutableArray<SubscriptionWithoutLock> snapshot;
-            List<TableEntriesFactory<TData>> factories;
-
-            lock (_gate)
-            {
-                snapshot = _subscriptions;
-                factories = _map.Values.ToList();
-            }
-
-            // let table manager know that we want to refresh factories.
-            for (var i = 0; i < snapshot.Length; i++)
-            {
-                foreach (var factory in factories)
-                {
-                    factory.OnRefreshed();
-
-                    snapshot[i].AddOrUpdate(factory, newFactory: false);
-                }
-            }
-        }
-
         protected void AddAggregateKey(object data, object aggregateKey)
         {
             _aggregateKeyMap.Add(GetItemKey(data), aggregateKey);

src/VisualStudio/Core/Def/Implementation/TableDataSource/TableItem.cs

@@ -94,17 +94,17 @@ public string ProjectName
                 var projectId = Extensions.GetProjectId(Primary);
                 if (projectId == null)
                 {
-                    return null;
+                    return ServicesVSResources.Unknown;
                 }
 
                 if (_cache == null)
                 {
                     // return single project name
-                    return Workspace.GetProjectName(projectId);
+                    return Workspace.GetProjectName(projectId) ?? ServicesVSResources.Unknown;
                 }
 
                 // return joined project names
-                return _cache.GetProjectName(Workspace);
+                return _cache.GetProjectName(Workspace) ?? ServicesVSResources.Unknown;
             }
         }
 

src/VisualStudio/Core/Def/Implementation/TableDataSource/VisualStudioDiagnosticListTable.BuildTableDataSource.cs

@@ -257,10 +257,40 @@ public override bool TryNavigateTo(int index, bool previewTab)
                         return false;
                     }
 
-                    return TryNavigateTo(item.Workspace, item.DocumentId,
+                    return TryNavigateTo(item.Workspace, GetProperDocumentId(item),
                                          item.DataLocation?.OriginalStartLine ?? 0, item.DataLocation?.OriginalStartColumn ?? 0, previewTab);
                 }
 
+                private DocumentId GetProperDocumentId(DiagnosticData data)
+                {
+                    // check whether documentId still exist. it might have changed if project it belong to has reloaded.
+                    var solution = data.Workspace.CurrentSolution;
+                    if (solution.GetDocument(data.DocumentId) != null)
+                    {
+                        return data.DocumentId;
+                    }
+
+                    // okay, documentId no longer exist in current solution, find it by file path.
+                    if (string.IsNullOrWhiteSpace(data.DataLocation?.OriginalFilePath))
+                    {
+                        // we don't have filepath
+                        return null;
+                    }
+
+                    var documentIds = solution.GetDocumentIdsWithFilePath(data.DataLocation.OriginalFilePath);
+                    foreach (var id in documentIds)
+                    {
+                        // found right documentId;
+                        if (id.ProjectId == data.ProjectId)
+                        {
+                            return id;
+                        }
+                    }
+
+                    // okay, there is no right one, take the first one if there is any
+                    return documentIds.FirstOrDefault();
+                }
+
                 protected override bool IsEquivalent(DiagnosticData item1, DiagnosticData item2)
                 {
                     // everything same except location

src/VisualStudio/Core/Def/Implementation/TableDataSource/VisualStudioDiagnosticListTable.cs

@@ -78,6 +78,9 @@ protected override void AddTableSourceIfNecessary(Solution solution)
         {
             if (solution.ProjectIds.Count == 0)
             {
+                // whenever there is a change in solution, make sure we refresh static info
+                // of build errors so that things like project name correctly refreshed
+                _buildTableSource.RefreshAllFactories();
                 return;
             }
 
@@ -89,6 +92,9 @@ protected override void RemoveTableSourceIfNecessary(Solution solution)
         {
             if (solution.ProjectIds.Count > 0)
             {
+                // whenever there is a change in solution, make sure we refresh static info
+                // of build errors so that things like project name correctly refreshed
+                _buildTableSource.RefreshAllFactories();
                 return;
             }
 

src/VisualStudio/Core/Def/ServicesVSResources.Designer.cs

@@ -1146,6 +1146,15 @@ internal class ServicesVSResources {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to &lt;Unknown&gt;.
+        /// </summary>
+        internal static string Unknown {
+            get {
+                return ResourceManager.GetString("Unknown", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Unknown rename type.
         /// </summary>

src/VisualStudio/Core/Def/ServicesVSResources.resx

@@ -516,4 +516,7 @@ Use the dropdown to view and switch to other projects this file may belong to.</
   <data name="FullSolutionAnalysisOff" xml:space="preserve">
     <value>Low memory detected. Full solution analysis disabled for this solution.</value>
   </data>
+  <data name="Unknown" xml:space="preserve">
+    <value>&lt;Unknown&gt;</value>
+  </data>
 </root>
\ No newline at end of file