Fix the correct file.

Author: addabis

src/PostSharp.Engineering.BuildTools/Resources/DockerBuild.ps1

@@ -145,20 +145,21 @@ if (-not $KeepEnv)
     }
 
     # Add git identity to environment
-    $env:GIT_USER_EMAIL = git config --global user.email
-    $env:GIT_USER_NAME = git config --global user.name
-
     if ($env:IS_TEAMCITY_AGENT)
     {
-        if (-not $env:GIT_USER_EMAIL)
-        {
-            $env:GIT_USER_EMAIL = '[email protected]'
-        }
-        if (-not $env:GIT_USER_NAME)
+        # On TeamCity agents, check if the environment variables are set.
+        if (-not $env:GIT_USER_EMAIL -or -not $env:GIT_USER_NAME)
         {
-            $env:GIT_USER_NAME = 'teamcity'
+            Write-Error "On TeamCity agents, the GIT_USER_EMAIL and GIT_USER_NAME environment variables must be set."
+            exit 1
         }
     }
+    else
+    {
+        # On developer machines, use the current git user.
+        $env:GIT_USER_EMAIL = git config --global user.email
+        $env:GIT_USER_NAME = git config --global user.name
+    }
 
     New-EnvJson -EnvironmentVariableList $EnvironmentVariables
 }