fix: respect AutoSave flag for grouping policy operations

The EnableAutoSave(false) setting was not being respected for RBAC/grouping
policy operations. When AutoSave was disabled, policy operations (AddPolicy,
RemovePolicy, UpdatePolicy) correctly skipped adapter saving, but grouping
policy operations (AddGroupingPolicy, RemoveGroupingPolicy, etc.) still
saved to the adapter.

Root Cause:
The SetAutoSave() method only iterated through policy assertions (section "p")
to set the AutoSave flag. It never set the flag for role assertions (section "g"),
even though RoleAssertion has its own PolicyManager with an AutoSave property.

Solution:
Modified SetAutoSave() to also configure the AutoSave flag for role/grouping
assertions, with a safety check for models without role definitions.

Changes:
- Casbin/Extensions/Model/ModelExtension.cs: Updated SetAutoSave() to handle
  both policy and role assertions
- Casbin.UnitTests/ModelTests/EnforcerTest.cs: Added comprehensive tests for
  sync and async grouping policy operations
- Casbin.UnitTests/Mock/MockSingleAdapter.cs: Created test helper to track
  adapter save operations

All 363 unit tests pass with no regressions.

Author: thoraj

Casbin.UnitTests/Mock/MockSingleAdapter.cs

@@ -0,0 +1,66 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Casbin.Model;
+using Casbin.Persist;
+using Casbin.Persist.Adapter.File;
+
+namespace Casbin.UnitTests.Mock;
+
+public class MockSingleAdapter : FileAdapter, ISingleAdapter
+{
+    public List<string> SavedPolicies { get; } = new();
+
+    public MockSingleAdapter(string filePath) : base(filePath)
+    {
+    }
+
+    public void AddPolicy(string section, string policyType, IPolicyValues rule)
+    {
+        SavedPolicies.Add($"AddPolicy: {section}.{policyType} {rule.ToText()}");
+    }
+
+    public Task AddPolicyAsync(string section, string policyType, IPolicyValues rule)
+    {
+        SavedPolicies.Add($"AddPolicyAsync: {section}.{policyType} {rule.ToText()}");
+#if NET452
+        return Task.FromResult(0);
+#else
+        return Task.CompletedTask;
+#endif
+    }
+
+    public void UpdatePolicy(string section, string policyType, IPolicyValues oldRule, IPolicyValues newRule)
+    {
+        SavedPolicies.Add($"UpdatePolicy: {section}.{policyType} {oldRule.ToText()} -> {newRule.ToText()}");
+    }
+
+    public Task UpdatePolicyAsync(string section, string policyType, IPolicyValues oldRules, IPolicyValues newRules)
+    {
+        SavedPolicies.Add($"UpdatePolicyAsync: {section}.{policyType} {oldRules.ToText()} -> {newRules.ToText()}");
+#if NET452
+        return Task.FromResult(0);
+#else
+        return Task.CompletedTask;
+#endif
+    }
+
+    public void RemovePolicy(string section, string policyType, IPolicyValues rule)
+    {
+        SavedPolicies.Add($"RemovePolicy: {section}.{policyType} {rule.ToText()}");
+    }
+
+    public Task RemovePolicyAsync(string section, string policyType, IPolicyValues rule)
+    {
+        SavedPolicies.Add($"RemovePolicyAsync: {section}.{policyType} {rule.ToText()}");
+#if NET452
+        return Task.FromResult(0);
+#else
+        return Task.CompletedTask;
+#endif
+    }
+
+    public void ClearSavedPolicies()
+    {
+        SavedPolicies.Clear();
+    }
+}

Casbin.UnitTests/ModelTests/EnforcerTest.cs

@@ -939,6 +939,59 @@ public async Task TestEnableAutoSaveAsync()
         Assert.True(await e.EnforceAsync("bob", "data2", "write"));
     }
 
+    [Fact]
+    public void TestAutoSaveGroupingPolicy()
+    {
+        // This test verifies that AddGroupingPolicy() respects the AutoSave flag.
+        // When AutoSave is disabled, grouping policy changes should not be saved to the adapter.
+
+        MockSingleAdapter adapter = new("Examples/rbac_policy.csv");
+        Enforcer e = new("Examples/rbac_model.conf", adapter);
+
+        // Verify initial state: alice has data2_admin role
+        Assert.True(e.HasGroupingPolicy("alice", "data2_admin"));
+        Assert.False(e.HasGroupingPolicy("bob", "data2_admin"));
+
+        adapter.ClearSavedPolicies();
+        e.EnableAutoSave(false);
+
+        // Because AutoSave is disabled, the grouping policy change should only affect
+        // the policy in Casbin enforcer, it should NOT call the adapter.
+        e.AddGroupingPolicy("bob", "data2_admin");
+
+        // Verify the change is in memory
+        Assert.True(e.HasGroupingPolicy("bob", "data2_admin"));
+
+        // Verify the adapter was NOT called because AutoSave is disabled
+        Assert.Empty(adapter.SavedPolicies);
+    }
+
+    [Fact]
+    public async Task TestAutoSaveGroupingPolicyAsync()
+    {
+        // This test verifies that AddGroupingPolicyAsync() respects the AutoSave flag.
+        // When AutoSave is disabled, grouping policy changes should not be saved to the adapter.
+
+        MockSingleAdapter adapter = new("Examples/rbac_policy.csv");
+        Enforcer e = new("Examples/rbac_model.conf", adapter);
+
+        // Verify initial state
+        Assert.True(e.HasGroupingPolicy("alice", "data2_admin"));
+        Assert.False(e.HasGroupingPolicy("bob", "data2_admin"));
+
+        adapter.ClearSavedPolicies();
+        e.EnableAutoSave(false);
+
+        // Add grouping policy with AutoSave disabled
+        await e.AddGroupingPolicyAsync("bob", "data2_admin");
+
+        // Verify the change is in memory
+        Assert.True(e.HasGroupingPolicy("bob", "data2_admin"));
+
+        // Verify the adapter was NOT called because AutoSave is disabled
+        Assert.Empty(adapter.SavedPolicies);
+    }
+
     [Fact]
     public void TestInitWithAdapter()
     {

Casbin/Extensions/Model/ModelExtension.cs

@@ -228,10 +228,20 @@ public static async Task<bool> SavePolicyAsync(this IModel model)
 
         public static void SetAutoSave(this IModel model, bool autoSave)
         {
+            // Set AutoSave for policy assertions (section "p")
             foreach (KeyValuePair<string, PolicyAssertion> pair in model.Sections.GetPolicyAssertions())
             {
                 pair.Value.PolicyManager.AutoSave = autoSave;
             }
+
+            // Set AutoSave for role/grouping assertions (section "g") if they exist
+            if (model.Sections.ContainsSection(PermConstants.Section.RoleSection))
+            {
+                foreach (KeyValuePair<string, RoleAssertion> pair in model.Sections.GetRoleAssertions())
+                {
+                    pair.Value.PolicyManager.AutoSave = autoSave;
+                }
+            }
         }
 
         public static IPolicyManager GetPolicyManager(this IModel model, string section,