option to exit 0 instead of 1 when interaction disabled

src/shared/Core/Authentication/AuthenticationBase.cs

@@ -90,6 +90,11 @@ protected void ThrowIfUserInteractionDisabled()
         {
             if (!Context.Settings.IsInteractionAllowed)
             {
+                if (Context.Settings.SilentExit)
+                {
+                    Environment.Exit(0);
+                }
+
                 string envName = Constants.EnvironmentVariables.GcmInteractive;
                 string cfgName = string.Format("{0}.{1}",
                     Constants.GitConfiguration.Credential.SectionName,
@@ -104,6 +109,11 @@ protected void ThrowIfGuiPromptsDisabled()
         {
             if (!Context.Settings.IsGuiPromptsEnabled)
             {
+                if (Context.Settings.SilentExit)
+                {
+                    Environment.Exit(0);
+                }
+
                 Context.Trace.WriteLine($"{Constants.EnvironmentVariables.GitTerminalPrompts} is 0; GUI prompts have been disabled.");
                 throw new Trace2InvalidOperationException(Context.Trace2, "Cannot show prompt because GUI prompts have been disabled.");
             }
@@ -113,6 +123,11 @@ protected void ThrowIfTerminalPromptsDisabled()
         {
             if (!Context.Settings.IsTerminalPromptsEnabled)
             {
+                if (Context.Settings.SilentExit)
+                {
+                    Environment.Exit(0);
+                }
+
                 Context.Trace.WriteLine($"{Constants.EnvironmentVariables.GitTerminalPrompts} is 0; terminal prompts have been disabled.");
                 throw new Trace2InvalidOperationException(Context.Trace2, "Cannot prompt because terminal prompts have been disabled.");
             }
@@ -122,6 +137,11 @@ protected void ThrowIfWindowCancelled(WindowViewModel viewModel)
         {
             if (!viewModel.WindowResult)
             {
+                if (Context.Settings.SilentExit)
+                {
+                    Environment.Exit(0);
+                }
+
                 throw new Exception("User cancelled dialog.");
             }
         }

src/shared/Core/Settings.cs

@@ -82,6 +82,11 @@ public interface ISettings : IDisposable
         /// </remarks>
         bool IsInteractionAllowed { get; }
 
+        /// <summary>
+        /// Whether to exit silently with status 0 in cases such interaction not allowed and terminal prompts disabled.
+        /// </summary>
+        bool SilentExit { get; }
+
         /// <summary>
         /// Get if tracing has been enabled, returning trace setting value in the out parameter.
         /// </summary>
@@ -558,6 +563,9 @@ public bool IsInteractionAllowed
             }
         }
 
+        public bool SilentExit =>
+            !TryGetSetting("GCM_SILENT_EXIT", GitCredCfg.SectionName, "silentExit", out string value) || value.ToBooleanyOrDefault(false);
+
         public bool GetTracingEnabled(out string value) =>
             TryGetSetting(KnownEnvars.GcmTrace,
                 KnownGitCfg.Credential.SectionName,

src/shared/TestInfrastructure/Objects/TestSettings.cs

@@ -17,6 +17,8 @@ public class TestSettings : ISettings
 
         public bool IsInteractionAllowed { get; set; } = true;
 
+        public bool SilentExit {get; } = false;
+
         public string Trace { get; set; }
 
         public bool IsSecretTracingEnabled { get; set; }