From 0cc930929aa04d56b5f7b7c358024dd31a96aa60 Mon Sep 17 00:00:00 2001
From: Brandon Ording <bording@gmail.com>
Date: Wed, 21 Apr 2021 14:48:26 -0400
Subject: [PATCH 1/2] Add global mutex to prevent concurrent use

---
 src/GitVersion.App/GitVersionExecutor.cs | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/GitVersion.App/GitVersionExecutor.cs b/src/GitVersion.App/GitVersionExecutor.cs
index 1a4fa2907d..0631ff2deb 100644
--- a/src/GitVersion.App/GitVersionExecutor.cs
+++ b/src/GitVersion.App/GitVersionExecutor.cs
@@ -1,6 +1,7 @@
 using System;
 using System.IO;
 using System.Reflection;
+using System.Threading;
 using GitVersion.Configuration;
 using GitVersion.Extensions;
 using GitVersion.Logging;
@@ -56,8 +57,16 @@ public int Execute(GitVersionOptions gitVersionOptions)
 
         private int RunGitVersionTool(GitVersionOptions gitVersionOptions)
         {
+            var mutexName = gitVersionOptions.WorkingDirectory.Replace("\\", "");
+            using var mutex = new Mutex(true, $@"Global\{mutexName}", out var acquired);
+
             try
             {
+                if (!acquired)
+                {
+                    mutex.WaitOne();
+                }
+
                 var variables = gitVersionCalculateTool.CalculateVersionVariables();
 
                 var configuration = configProvider.Provide(overrideConfig: gitVersionOptions.ConfigInfo.OverrideConfig);
@@ -92,6 +101,10 @@ private int RunGitVersionTool(GitVersionOptions gitVersionOptions)
                 }
                 return 1;
             }
+            finally
+            {
+                mutex.ReleaseMutex();
+            }
 
             return 0;
         }

From df0d8dea2b08fa5b81b91279d687ac0ada30033e Mon Sep 17 00:00:00 2001
From: Brandon Ording <bording@gmail.com>
Date: Wed, 28 Apr 2021 15:06:39 -0400
Subject: [PATCH 2/2] Use Path.DirectorySeparatorChar to create mutex name

---
 src/GitVersion.App/GitVersionExecutor.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/GitVersion.App/GitVersionExecutor.cs b/src/GitVersion.App/GitVersionExecutor.cs
index 0631ff2deb..0f10152c13 100644
--- a/src/GitVersion.App/GitVersionExecutor.cs
+++ b/src/GitVersion.App/GitVersionExecutor.cs
@@ -57,7 +57,7 @@ public int Execute(GitVersionOptions gitVersionOptions)
 
         private int RunGitVersionTool(GitVersionOptions gitVersionOptions)
         {
-            var mutexName = gitVersionOptions.WorkingDirectory.Replace("\\", "");
+            var mutexName = gitVersionOptions.WorkingDirectory.Replace(Path.DirectorySeparatorChar.ToString(), "");
             using var mutex = new Mutex(true, $@"Global\{mutexName}", out var acquired);
 
             try