.Net: Fix OllamaPromptExecutionSettings Clone() method to preserve Ollama-specific settings (#13218)

- [x] Analyze the repository structure and understand the issue
- [x] Review OpenAIPromptExecutionSettings implementation as reference
- [x] Build and test the current Ollama connector
- [x] Add Clone() method to OllamaPromptExecutionSettings
- [x] Add Freeze() method to OllamaPromptExecutionSettings
- [x] Change Stop property type from List<string> to IList<string> for
consistency with OpenAI
- [x] Add comprehensive tests for Clone() method
- [x] Add test for Freeze() method
- [x] Add ServiceId property to Clone() method (code review feedback)
- [x] Add test to verify ServiceId is cloned correctly
- [x] Build and test to verify all changes work correctly

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<details>

<summary>Original prompt</summary>

> 
> ----
> 
> *This section details on the original issue you should resolve*
> 
> <issue_title>.Net: Bug: OllamaPromptExecutionSettings Clone() method
does not clone Ollama specific settings</issue_title>
> <issue_description>**Describe the bug**
> Calling `Clone()` on `OllamaPromptExecutionSettings` instance returns
`PromptExecutionSettings` with Temperature, TopK, TopP and MaxTokens
settings lost
> 
> **To Reproduce**
> ```c#
> var testSettings = new OllamaPromptExecutionSettings { Temperature =
(float)temperature, TopP = (float)topP };
> 
> // Throws `InvalidCastExeception` always as testSettings is of
`PromptExecutionSettings` type.
> // Additionally, testSettings do not contain temperature or topP
parameter values (nothing in ExtensionData either)
> var result = (OllamaPromptExecutionSettings) testSettings.Clone();
> ```
> 
> **Expected behavior**
> Object is cloned correctly like in OpenAI provider
> 
> **Platform**
>  - Language: C#
>  - Source: 1.65.0
>  - AI model: Ollama qwen3:32b
>  - IDE: Visual Studio
>  - OS: Windows
> 
> **Additional context**
> 
> I think it should work like `OpenAIPromptExecutionSettings`, where all
information is properly Cloned.
> </issue_description>
> 
> <agent_instructions>Add the following methods to
`OllamaPromptExecutionSettings.cs`
> 1. `Clone`
> 2. `FromExecutionSettings`
> 
> Use the implementations in `OpenAIPromptExecutionSettings.cs` as
examples for how the methods should be implemented.</agent_instructions>
> 
> ## Comments on the Issue (you are @copilot in this section)
> 
> <comments>
> </comments>
> 


</details>
Fixes #13217

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Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: markwallace-microsoft <[email protected]>

Author: Copilot

dotnet/src/Connectors/Connectors.Ollama.UnitTests/Settings/OllamaPromptExecutionSettingsTests.cs

@@ -1,5 +1,7 @@
 // Copyright (c) Microsoft. All rights reserved.
 
+using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Text.Json;
 using Microsoft.SemanticKernel;
@@ -82,4 +84,135 @@ public void FromExecutionSettingsShouldRestoreFunctionChoiceBehavior()
         // Assert
         Assert.Equal(functionChoiceBehavior, result.FunctionChoiceBehavior);
     }
+
+    [Fact]
+    public void PromptExecutionSettingsCloneWorksAsExpected()
+    {
+        // Arrange
+        string configPayload = """
+        {
+            "temperature": 0.5,
+            "top_p": 0.9,
+            "top_k": 100,
+            "num_predict": 50,
+            "stop": ["stop me"]
+        }
+        """;
+        var executionSettings = JsonSerializer.Deserialize<OllamaPromptExecutionSettings>(configPayload);
+
+        // Act
+        var clone = executionSettings!.Clone();
+
+        // Assert
+        Assert.NotNull(clone);
+        Assert.IsType<OllamaPromptExecutionSettings>(clone);
+        var ollamaClone = (OllamaPromptExecutionSettings)clone;
+        Assert.Equal(executionSettings.ModelId, ollamaClone.ModelId);
+        Assert.Equal(executionSettings.Temperature, ollamaClone.Temperature);
+        Assert.Equal(executionSettings.TopP, ollamaClone.TopP);
+        Assert.Equal(executionSettings.TopK, ollamaClone.TopK);
+        Assert.Equal(executionSettings.NumPredict, ollamaClone.NumPredict);
+        Assert.Equal(executionSettings.Stop, ollamaClone.Stop);
+        Assert.Equivalent(executionSettings.ExtensionData, ollamaClone.ExtensionData);
+    }
+
+    [Fact]
+    public void ClonePreservesAllOllamaSpecificSettings()
+    {
+        // Arrange
+        var testSettings = new OllamaPromptExecutionSettings
+        {
+            Temperature = 0.7f,
+            TopP = 0.85f,
+            TopK = 50,
+            NumPredict = 100,
+            Stop = new List<string> { "END", "STOP" },
+            ModelId = "llama2"
+        };
+
+        // Act
+        var result = (OllamaPromptExecutionSettings)testSettings.Clone();
+
+        // Assert
+        Assert.NotNull(result);
+        Assert.NotSame(testSettings, result);
+        Assert.Equal(testSettings.Temperature, result.Temperature);
+        Assert.Equal(testSettings.TopP, result.TopP);
+        Assert.Equal(testSettings.TopK, result.TopK);
+        Assert.Equal(testSettings.NumPredict, result.NumPredict);
+        Assert.Equal(testSettings.ModelId, result.ModelId);
+        Assert.NotSame(testSettings.Stop, result.Stop);
+        Assert.Equal(testSettings.Stop, result.Stop);
+    }
+
+    [Fact]
+    public void CloneReturnsOllamaPromptExecutionSettingsType()
+    {
+        // This test verifies the exact issue from the bug report
+        // Arrange
+        var testSettings = new OllamaPromptExecutionSettings
+        {
+            Temperature = 0.7f,
+            TopP = 0.9f,
+            ServiceId = "test-service"
+        };
+
+        // Act
+        var cloned = testSettings.Clone();
+
+        // Assert - Should not throw InvalidCastException
+        var result = (OllamaPromptExecutionSettings)cloned;
+        Assert.NotNull(result);
+        Assert.Equal(testSettings.Temperature, result.Temperature);
+        Assert.Equal(testSettings.TopP, result.TopP);
+        Assert.Equal(testSettings.ServiceId, result.ServiceId);
+    }
+
+    [Fact]
+    public void ClonePreservesServiceId()
+    {
+        // Arrange
+        var testSettings = new OllamaPromptExecutionSettings
+        {
+            ServiceId = "my-ollama-service",
+            ModelId = "llama2",
+            Temperature = 0.8f
+        };
+
+        // Act
+        var cloned = (OllamaPromptExecutionSettings)testSettings.Clone();
+
+        // Assert
+        Assert.Equal(testSettings.ServiceId, cloned.ServiceId);
+        Assert.Equal(testSettings.ModelId, cloned.ModelId);
+        Assert.Equal(testSettings.Temperature, cloned.Temperature);
+    }
+
+    [Fact]
+    public void PromptExecutionSettingsFreezeWorksAsExpected()
+    {
+        // Arrange
+        var executionSettings = new OllamaPromptExecutionSettings
+        {
+            Temperature = 0.5f,
+            TopP = 0.9f,
+            TopK = 100,
+            NumPredict = 50,
+            Stop = new List<string> { "STOP" }
+        };
+
+        // Act
+        executionSettings.Freeze();
+
+        // Assert
+        Assert.True(executionSettings.IsFrozen);
+        Assert.Throws<InvalidOperationException>(() => executionSettings.Temperature = 1);
+        Assert.Throws<InvalidOperationException>(() => executionSettings.TopP = 1);
+        Assert.Throws<InvalidOperationException>(() => executionSettings.TopK = 1);
+        Assert.Throws<InvalidOperationException>(() => executionSettings.NumPredict = 1);
+        Assert.Throws<NotSupportedException>(() => executionSettings.Stop?.Add("END"));
+
+        executionSettings.Freeze(); // idempotent
+        Assert.True(executionSettings.IsFrozen);
+    }
 }

dotnet/src/Connectors/Connectors.Ollama/Services/OllamaTextGenerationService.cs

@@ -2,6 +2,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Net.Http;
 using System.Runtime.CompilerServices;
 using System.Text;

dotnet/src/Connectors/Connectors.Ollama/Settings/OllamaPromptExecutionSettings.cs

@@ -51,7 +51,7 @@ public static OllamaPromptExecutionSettings FromExecutionSettings(PromptExecutio
     /// </summary>
     [JsonPropertyName("stop")]
     [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
-    public List<string>? Stop
+    public IList<string>? Stop
     {
         get => this._stop;
 
@@ -131,9 +131,42 @@ public int? NumPredict
         }
     }
 
+    /// <inheritdoc/>
+    public override void Freeze()
+    {
+        if (this.IsFrozen)
+        {
+            return;
+        }
+
+        base.Freeze();
+
+        if (this._stop is not null)
+        {
+            this._stop = new System.Collections.ObjectModel.ReadOnlyCollection<string>(this._stop);
+        }
+    }
+
+    /// <inheritdoc/>
+    public override PromptExecutionSettings Clone()
+    {
+        return new OllamaPromptExecutionSettings()
+        {
+            ModelId = this.ModelId,
+            ServiceId = this.ServiceId,
+            ExtensionData = this.ExtensionData is not null ? new Dictionary<string, object>(this.ExtensionData) : null,
+            Temperature = this.Temperature,
+            TopP = this.TopP,
+            TopK = this.TopK,
+            NumPredict = this.NumPredict,
+            Stop = this.Stop is not null ? new List<string>(this.Stop) : null,
+            FunctionChoiceBehavior = this.FunctionChoiceBehavior,
+        };
+    }
+
     #region private
 
-    private List<string>? _stop;
+    private IList<string>? _stop;
     private float? _temperature;
     private float? _topP;
     private int? _topK;