Fixes a nasty Process.WaitForExit() race condition (#125)

phmonte · Feb 13, 2020 · 7723232 · 7723232
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diff --git a/ReleaseNotes.md b/ReleaseNotes.md
@@ -1,6 +1,7 @@
 # 2.5.1
 
 - [Fix] Removed the explicit encoding parameter when generating a `SourceText` in Buildalyzer.Workspaces (#128)
+- [Fix] Fixes a race condition in `ProcessRunner` in `Process.WaitForExit()` calls (#125, thanks @duncanawoods)
 
 # 2.5.0
 

diff --git a/src/Buildalyzer/Environment/ProcessRunner.cs b/src/Buildalyzer/Environment/ProcessRunner.cs
@@ -90,7 +90,18 @@ private void ProcessExited(object sender, EventArgs e)
 
         public void WaitForExit() => Process.WaitForExit();
 
-        public bool WaitForExit(int timeout) => Process.WaitForExit(timeout);
+        public bool WaitForExit(int timeout)
+        {
+            bool exited = Process.WaitForExit(timeout);
+            if (exited)
+            {
+                // To ensure that asynchronous event handling has been completed, call the WaitForExit() overload that takes no parameter after receiving a true from this overload.
+                // From https://docs.microsoft.com/en-us/dotnet/api/system.diagnostics.process.waitforexit?redirectedfrom=MSDN&view=netcore-3.1#System_Diagnostics_Process_WaitForExit_System_Int32_
+                // See also https://github.com/dotnet/runtime/issues/27128
+                Process.WaitForExit();
+            }
+            return exited;
+        }
 
         public void Dispose()
         {