From 0268ff2baadf237ac9a32550f6e737698856b1bf Mon Sep 17 00:00:00 2001
From: Drew Noakes <git@drewnoakes.com>
Date: Wed, 10 Jul 2019 18:36:57 +1000
Subject: [PATCH] Fix NRE due to dataflow race

It was possible for ProcessProjectChanged to be called before _broadcastBlock was assigned, leading to a NRE when it was dereferenced.
---
 .../ProjectSystem/VS/PotentialEditorConfigDataSource.cs        | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/Microsoft.VisualStudio.ProjectSystem.Managed.VS/ProjectSystem/VS/PotentialEditorConfigDataSource.cs b/src/Microsoft.VisualStudio.ProjectSystem.Managed.VS/ProjectSystem/VS/PotentialEditorConfigDataSource.cs
index f88227e86c5..27738c9b528 100644
--- a/src/Microsoft.VisualStudio.ProjectSystem.Managed.VS/ProjectSystem/VS/PotentialEditorConfigDataSource.cs
+++ b/src/Microsoft.VisualStudio.ProjectSystem.Managed.VS/ProjectSystem/VS/PotentialEditorConfigDataSource.cs
@@ -58,6 +58,8 @@ protected override void Initialize()
         {
             base.Initialize();
 
+            _broadcastBlock = DataflowBlockSlim.CreateBroadcastBlock<IProjectVersionedValue<FileWatchData>>(nameFormat: nameof(PotentialEditorConfigDataSource) + "Broadcast {1}");
+
             IDisposable projectRuleSourceLink = _project.Services.ProjectSubscription.ProjectRuleSource.SourceBlock.LinkToAsyncAction(ProcessProjectChanged, ruleNames: PotentialEditorConfigFiles.SchemaName);
 
             IDisposable join = JoinUpstreamDataSources(_project.Services.ProjectSubscription.ProjectRuleSource);
@@ -66,7 +68,6 @@ protected override void Initialize()
             _disposables.AddDisposable(projectRuleSourceLink);
             _disposables.AddDisposable(join);
 
-            _broadcastBlock = DataflowBlockSlim.CreateBroadcastBlock<IProjectVersionedValue<FileWatchData>>(nameFormat: nameof(PotentialEditorConfigDataSource) + "Broadcast {1}");
             _publicBlock = _broadcastBlock.SafePublicize();
         }