Fix null reference bugs and unsafe code patterns across codebase

src/CLI/ApiClientCodeGen.CLI/Commands/JMeterCommand.cs

@@ -75,7 +75,8 @@ public override int Execute(CommandContext context, Settings settings, Cancellat
             var outputPath = settings.OutputPath;
             if (!Directory.Exists(outputPath))
             {
-                outputPath = Path.Combine(Path.GetDirectoryName(settings.SwaggerFile)!, settings.OutputPath);
+                var swaggerDirectory = Path.GetDirectoryName(settings.SwaggerFile) ?? Directory.GetCurrentDirectory();
+                outputPath = Path.Combine(swaggerDirectory, settings.OutputPath);
             }
 
             var directoryInfo = new DirectoryInfo(outputPath);

src/CLI/ApiClientCodeGen.CLI/Commands/OpenApiGeneratorCommand.cs

@@ -58,7 +58,7 @@ public OpenApiGeneratorCommand(
             this.console = console ?? throw new ArgumentNullException(nameof(console));
             this.progressReporter = progressReporter ?? throw new ArgumentNullException(nameof(progressReporter));
             this.options = options ?? throw new ArgumentNullException(nameof(options));
-            this.factory = factory;
+            this.factory = factory ?? throw new ArgumentNullException(nameof(factory));
             this.processLauncher = processLauncher ?? throw new ArgumentNullException(nameof(processLauncher));
             this.dependencyInstaller =
                 dependencyInstaller ?? throw new ArgumentNullException(nameof(dependencyInstaller));

src/Core/ApiClientCodeGen.Core/Extensions/StringExtensions.cs

@@ -73,7 +73,14 @@ public static string GetDescription<T>(this T e) where T : Enum, IConvertible
             {
                 if (val == e.ToInt32(CultureInfo.InvariantCulture))
                 {
-                    var memInfo = type.GetMember(type.GetEnumName(val));
+                    var enumName = type.GetEnumName(val);
+                    if (enumName == null)
+                        continue;
+
+                    var memInfo = type.GetMember(enumName);
+                    if (memInfo.Length == 0)
+                        continue;
+
                     var descriptionAttribute = memInfo[0]
                         .GetCustomAttributes(typeof(DescriptionAttribute), false)
                         .FirstOrDefault() as DescriptionAttribute;

src/Core/ApiClientCodeGen.Core/External/PathProvider.cs

@@ -51,15 +51,22 @@ public static string GetNpmPath(
             if (Environment.OSVersion.Platform is PlatformID.MacOSX or PlatformID.Unix || withoutPath)
                 return "npm";
 
-            if (string.IsNullOrWhiteSpace(programFiles))
-                programFiles = Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles);
+            var programFilesPath = programFiles;
+            if (string.IsNullOrWhiteSpace(programFilesPath))
+                programFilesPath = Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles);
 
-            if (string.IsNullOrWhiteSpace(programFiles64))
-                programFiles64 = programFiles!.Replace(" (x86)", string.Empty);
+            // If still null/empty after getting from environment, return npm command without path
+            if (string.IsNullOrWhiteSpace(programFilesPath))
+                return "npm";
+
+            // At this point programFilesPath is guaranteed to be non-null/non-empty
+            var effectiveProgramFiles64 = !string.IsNullOrWhiteSpace(programFiles64)
+                ? programFiles64
+                : programFilesPath!.Replace(" (x86)", string.Empty);
 
-            var npmCommand = Path.Combine(programFiles, "nodejs\\npm.cmd");
+            var npmCommand = Path.Combine(programFilesPath!, "nodejs\\npm.cmd");
             if (!File.Exists(npmCommand))
-                npmCommand = Path.Combine(programFiles64, "nodejs\\npm.cmd");
+                npmCommand = Path.Combine(effectiveProgramFiles64, "nodejs\\npm.cmd");
 
             return File.Exists(npmCommand) ? npmCommand : string.Empty;
         }

src/Core/ApiClientCodeGen.Core/Generators/CSharpFileMerger.cs

@@ -36,9 +36,12 @@ public static string MergeFilesAndDeleteSource(string output)
             finally
             {
                 ActionExtensions.SafeInvoke(
-                    () => Directory.Delete(
-                        Directory.GetParent(output)!.FullName,
-                        true));
+                    () =>
+                    {
+                        var parent = Directory.GetParent(output);
+                        if (parent != null)
+                            Directory.Delete(parent.FullName, true);
+                    });
             }
         }
 
@@ -51,9 +54,12 @@ public static void CopyFilesAndDeleteSource(string input, string output)
             finally
             {
                 ActionExtensions.SafeInvoke(
-                    () => Directory.Delete(
-                        Directory.GetParent(input)!.FullName,
-                        true));
+                    () =>
+                    {
+                        var parent = Directory.GetParent(input);
+                        if (parent != null)
+                            Directory.Delete(parent.FullName, true);
+                    });
             }
         }
 

src/Core/ApiClientCodeGen.Core/Generators/Kiota/KiotaCodeGenerator.cs

@@ -35,8 +35,9 @@ public string GenerateCode(IProgressReporter? pGenerateProgress)
         }
 
         pGenerateProgress?.Progress(30);
+        var swaggerDirectory = Path.GetDirectoryName(swaggerFile) ?? Directory.GetCurrentDirectory();
         string outputFolder = options.GenerateMultipleFiles
-            ? Path.GetDirectoryName(swaggerFile)
+            ? swaggerDirectory
             : Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString());
 
         if (!Directory.Exists(outputFolder))
@@ -46,15 +47,15 @@ public string GenerateCode(IProgressReporter? pGenerateProgress)
         RunKiotaGenerate(outputFolder);
 
         if (!options.GenerateMultipleFiles &&
-            File.Exists(Path.Combine(Path.GetDirectoryName(swaggerFile)!, KiotaLockFile)))
+            File.Exists(Path.Combine(swaggerDirectory, KiotaLockFile)))
         {
             File.Copy(
                 swaggerFile,
                 Path.Combine(outputFolder, swaggerFilename),
                 true);
 
             File.Copy(
-                Path.Combine(Path.GetDirectoryName(swaggerFile)!, KiotaLockFile),
+                Path.Combine(swaggerDirectory, KiotaLockFile),
                 Path.Combine(outputFolder, KiotaLockFile),
                 true);
 
@@ -78,7 +79,7 @@ public string GenerateCode(IProgressReporter? pGenerateProgress)
             {
                 File.Copy(
                     kiotaConfigFile,
-                    Path.Combine(Path.GetDirectoryName(swaggerFile)!, KiotaLockFile),
+                    Path.Combine(swaggerDirectory, KiotaLockFile),
                     true);
             }
         }
@@ -109,7 +110,8 @@ private void RunKiotaGenerate(string outputFolder)
 
     private void RunKiotaUpdate()
     {
-        var arguments = $" update -o \"{Path.GetDirectoryName(swaggerFile)!}\"";
+        var outputDirectory = Path.GetDirectoryName(swaggerFile) ?? Directory.GetCurrentDirectory();
+        var arguments = $" update -o \"{outputDirectory}\"";
         using var context = new DependencyContext("Kiota", $"{Command} {arguments}");
         processLauncher.Start(Command, arguments);
         context.Succeeded();

src/Core/ApiClientCodeGen.Core/Generators/NSwagStudio/NSwagStudioCodeGenerator.cs

@@ -48,9 +48,10 @@ public string GenerateCode(IProgressReporter? pGenerateProgress)
                 pGenerateProgress?.Progress(50);
 
                 var arguments = $"run \"{nswagStudioFile}\"";
+                var workingDirectory = Path.GetDirectoryName(nswagStudioFile) ?? Directory.GetCurrentDirectory();
 
                 using var context = new DependencyContext("NSwag Studio", $"{command} {arguments}");
-                processLauncher.Start(command, arguments, Path.GetDirectoryName(nswagStudioFile)!);
+                processLauncher.Start(command, arguments, workingDirectory);
                 context.Succeeded();
             }
 

src/Core/ApiClientCodeGen.Core/Generators/OpenApi/OpenApiCSharpCodeGenerator.cs

@@ -40,7 +40,7 @@ public OpenApiCSharpCodeGenerator(
 
         public string GenerateCode(IProgressReporter? pGenerateProgress)
         {
-            string arguments = null!;
+            string arguments = "";
             try
             {
                 pGenerateProgress?.Progress(10);
@@ -118,20 +118,22 @@ public string GenerateCode(IProgressReporter? pGenerateProgress)
                     arguments += openApiGeneratorOptions.CustomAdditionalProperties;
                 }
 
+                var swaggerDirectory = Path.GetDirectoryName(swaggerFile) ?? Directory.GetCurrentDirectory();
+
                 if (!string.IsNullOrWhiteSpace(openApiGeneratorOptions.TemplatesPath))
                 {
                     var templatesPath = openApiGeneratorOptions.TemplatesPath;
                     if (!Directory.Exists(templatesPath))
                     {
-                        templatesPath = Path.Combine(Path.GetDirectoryName(swaggerFile)!, templatesPath);
+                        templatesPath = Path.Combine(swaggerDirectory, templatesPath);
                     }
 
                     arguments += $"-t \"{templatesPath}\" ";
                 }
 
                 var java = javaPathProvider.GetJavaExePath();
                 using var context = new DependencyContext("OpenAPI Generator", $"{java} {arguments}");
-                processLauncher.Start(java, arguments, Path.GetDirectoryName(swaggerFile));
+                processLauncher.Start(java, arguments, swaggerDirectory);
                 context.Succeeded();
 
                 pGenerateProgress?.Progress(80);
@@ -158,7 +160,7 @@ public string GenerateCode(IProgressReporter? pGenerateProgress)
                 {
                     CSharpFileMerger.CopyFilesAndDeleteSource(
                         Path.Combine(output, "src", defaultNamespace),
-                        Path.GetDirectoryName(swaggerFile)!);
+                        swaggerDirectory);
                 }
 
                 return string.Empty;

src/Core/ApiClientCodeGen.Core/Generators/Refitter/RefitterCodeGenerator.cs

@@ -177,8 +177,10 @@ private string BuildRefitterArguments(string inputFile, string outputPath)
 
     private static string GetOutputFilePath(RefitterSettings? settings, string? workingDirectory)
     {
-        if (settings == null || workingDirectory == null)
-            return Path.Combine(workingDirectory ?? "", "Output.cs");
+        var effectiveWorkingDirectory = workingDirectory ?? Directory.GetCurrentDirectory();
+
+        if (settings == null)
+            return Path.Combine(effectiveWorkingDirectory, "Output.cs");
 
         var outputFolder = settings.OutputFolder ?? "";
         var outputFilename = settings.OutputFilename ?? "Output.cs";
@@ -188,7 +190,7 @@ private static string GetOutputFilePath(RefitterSettings? settings, string? work
             return Path.Combine(outputFolder, outputFilename);
         }
 
-        return Path.Combine(workingDirectory, outputFolder, outputFilename);
+        return Path.Combine(effectiveWorkingDirectory, outputFolder, outputFilename);
     }
 
     // Minimal representation of Refitter settings for JSON deserialization

src/Core/ApiClientCodeGen.Core/Installer/DependencyInstaller.cs

@@ -117,20 +117,43 @@ public void InstallKiota()
                 });
                 if (!kiotaVersion.StartsWith("1.30.0"))
                 { 
-                    //older or newer? i guess this should be handled.
+                    // Version mismatch detected, try to update to required version
+                    try
+                    {
+                        UpdateKiotaTool();
+                    }
+                    catch (ProcessLaunchException ex) when (ex.ErrorData?.Contains("is already installed") == true)
+                    {
+                        // Tool is already installed at correct version, ignore
+                        Logger.Instance.WriteLine("Kiota is already installed at the required version.");
+                    }
                 }
             }
             catch (Win32Exception)
             {
                 // if command doesn't exist Win32Exception is thrown.
-                command = PathProvider.GetDotNetPath();
-                arguments = "tool install --global Microsoft.OpenApi.Kiota --version 1.30.0";
-                using var context = new DependencyContext(command, $"{command} {arguments}");
-                processLauncher.Start(command, arguments);
-                context.Succeeded();
+                InstallKiotaTool();
             }
         }
 
+        private void InstallKiotaTool()
+        {
+            var command = PathProvider.GetDotNetPath();
+            var arguments = "tool install --global Microsoft.OpenApi.Kiota --version 1.30.0";
+            using var context = new DependencyContext(command, $"{command} {arguments}");
+            processLauncher.Start(command, arguments);
+            context.Succeeded();
+        }
+
+        private void UpdateKiotaTool()
+        {
+            var command = PathProvider.GetDotNetPath();
+            var arguments = "tool update --global Microsoft.OpenApi.Kiota --version 1.30.0";
+            using var context = new DependencyContext(command, $"{command} {arguments}");
+            processLauncher.Start(command, arguments);
+            context.Succeeded();
+        }
+
         public void InstallRefitter()
         {
             var command = PathProvider.GetDotNetPath();

src/Core/ApiClientCodeGen.Core/Installer/FileDownloader.cs

@@ -38,24 +38,34 @@ public string DownloadFile(
 
             Logger.Instance.WriteLine($"{outputFilename} downloaded successfully");
 
-            MoveFile(filePath, tempFile);
+            if (!MoveFile(filePath, tempFile))
+            {
+                // If move failed but temp file exists, use it directly as fallback
+                if (File.Exists(tempFile))
+                    return tempFile;
+
+                // If temp file also doesn't exist, the download likely failed
+                // Log warning but return expected path for backward compatibility
+                Logger.Instance.WriteLine($"Warning: Downloaded file may not exist at expected location: {filePath}");
+            }
 
             return filePath;
         }
 
         [ExcludeFromCodeCoverage]
-        private static void MoveFile(string filePath, string tempFile)
+        private static bool MoveFile(string filePath, string tempFile)
         {
             try
             {
                 if (File.Exists(filePath))
                     File.Delete(filePath);
                 File.Move(tempFile, filePath);
+                return true;
             }
             catch (Exception e)
             {
                 Logger.Instance.TrackError(e);
-
+                return false;
             }
         }
     }

src/Core/ApiClientCodeGen.Core/NpmHelper.cs

@@ -24,7 +24,7 @@ public static string GetPrefixPath()
             try
             {
                 var npm = GetNpmPath();
-                string prefix = null!;
+                string prefix = "";
 
                 using var context = new DependencyContext("npm config get prefix");
                 (processLauncher ?? new ProcessLauncher()).Start(
@@ -33,7 +33,7 @@ public static string GetPrefixPath()
                     o => prefix += o,
                     e => Logger.Instance.WriteLine(e));
                 context.Succeeded();
-                return prefix;
+                return string.IsNullOrWhiteSpace(prefix) ? null : prefix;
             }
             catch (Exception e)
             {

src/VSCode/src/utils/version-utils.ts

@@ -28,8 +28,14 @@ export function getExtensionVersion(context: vscode.ExtensionContext): string |
  * @returns 1 if version1 > version2, -1 if version1 < version2, 0 if equal
  */
 export function compareVersions(version1: string, version2: string): number {
-  const parts1 = version1.split('.').map(Number);
-  const parts2 = version2.split('.').map(Number);
+  const parts1 = version1.split('.').map(s => {
+    const num = parseInt(s, 10);
+    return isNaN(num) ? 0 : num;
+  });
+  const parts2 = version2.split('.').map(s => {
+    const num = parseInt(s, 10);
+    return isNaN(num) ? 0 : num;
+  });
 
   for (let i = 0; i < Math.max(parts1.length, parts2.length); i++) {
     const p1 = i < parts1.length ? parts1[i] : 0;