feat: enable nullability and set C# version to 9

.gitignore

@@ -447,6 +447,7 @@ $RECYCLE.BIN/
 ##
 ## Visual Studio Code
 ##
+.vscode/
 .vscode/*
 !.vscode/settings.json
 !.vscode/tasks.json

src/AWS.Deploy.CLI/AWSUtilities.cs

@@ -14,8 +14,8 @@ namespace AWS.Deploy.CLI
 {
     public interface IAWSUtilities
     {
-        Task<AWSCredentials> ResolveAWSCredentials(string profileName, string lastUsedProfileName);
-        string ResolveAWSRegion(string region, string lastRegionUsed);
+        Task<AWSCredentials> ResolveAWSCredentials(string profileName, string? lastUsedProfileName);
+        string ResolveAWSRegion(string region, string? lastRegionUsed);
     }
 
     public class AWSUtilities : IAWSUtilities
@@ -29,7 +29,7 @@ public AWSUtilities(IToolInteractiveService toolInteractiveService, IConsoleUtil
             _consoleUtilities = consoleUtilities;
         }
 
-        public async Task<AWSCredentials> ResolveAWSCredentials(string profileName, string lastUsedProfileName)
+        public async Task<AWSCredentials> ResolveAWSCredentials(string profileName, string? lastUsedProfileName)
         {
 
 
@@ -113,7 +113,7 @@ private async Task<bool> CanLoadCredentials(AWSCredentials credentials)
             }
         }
 
-        public string ResolveAWSRegion(string region, string lastRegionUsed)
+        public string ResolveAWSRegion(string region, string? lastRegionUsed)
         {
             if (!string.IsNullOrEmpty(region))
             {

src/AWS.Deploy.CLI/Commands/CommandFactory.cs

@@ -133,14 +133,14 @@ private Command BuildDeployCommand()
 
                     var callerIdentity = await _awsResourceQueryer.GetCallerIdentity();
 
-                    var session = new OrchestratorSession
+                    var session = new OrchestratorSession(
+                        projectDefinition,
+                        awsCredentials,
+                        awsRegion,
+                        callerIdentity.Account)
                     {
-                        AWSProfileName = profile,
-                        AWSCredentials = awsCredentials,
-                        AWSRegion = awsRegion,
-                        AWSAccountId = callerIdentity.Account,
-                        ProjectDefinition = projectDefinition,
-                        SystemCapabilities = systemCapabilities
+                        SystemCapabilities = systemCapabilities,
+                        AWSProfileName = profile
                     };
 
                     var dockerEngine = new DockerEngine.DockerEngine(projectDefinition);

src/AWS.Deploy.CLI/Commands/DeleteDeploymentCommand.cs

@@ -118,9 +118,9 @@ private async Task WaitForStackDelete(string stackName)
             throw new FailedToDeleteException($"Failed to delete {stackName} stack: {stack.StackStatus}");
         }
 
-        private async Task<Stack> StabilizeStack(string stackName)
+        private async Task<Stack?> StabilizeStack(string stackName)
         {
-            Stack stack;
+            Stack? stack;
             do
             {
                 stack = await GetStackAsync(stackName);
@@ -134,7 +134,7 @@ private async Task<Stack> StabilizeStack(string stackName)
             return stack;
         }
 
-        private async Task<Stack> GetStackAsync(string stackName)
+        private async Task<Stack?> GetStackAsync(string stackName)
         {
             try
             {

src/AWS.Deploy.CLI/Commands/DeployCommand.cs

@@ -102,7 +102,7 @@ public async Task ExecuteAsync(string stackName, bool saveCdkProject)
 
             var deployedApplication = deployedApplications.FirstOrDefault(x => string.Equals(x.Name, cloudApplicationName));
 
-            Recommendation selectedRecommendation = null;
+            Recommendation? selectedRecommendation = null;
 
             _toolInteractiveService.WriteLine();
 
@@ -148,6 +148,9 @@ public async Task ExecuteAsync(string stackName, bool saveCdkProject)
             // Apply the user enter project name to the recommendation so that any default settings based on project name are applied.
             selectedRecommendation.OverrideProjectName(cloudApplicationName);
 
+            if (_session.SystemCapabilities == null)
+                throw new SystemCapabilitiesNotProvidedException("The system capabilities were not provided.");
+
             var systemCapabilities = await _session.SystemCapabilities;
             if (selectedRecommendation.Recipe.DeploymentType == DeploymentTypes.CdkProject &&
                 !systemCapabilities.NodeJsMinVersionInstalled)
@@ -174,10 +177,7 @@ public async Task ExecuteAsync(string stackName, bool saveCdkProject)
 
             await ConfigureDeployment(selectedRecommendation, configurableOptionSettings, false);
 
-            var cloudApplication = new CloudApplication
-            {
-                Name = cloudApplicationName
-            };
+            var cloudApplication = new CloudApplication(cloudApplicationName, string.Empty);
 
             if (!ConfirmDeployment(selectedRecommendation))
             {
@@ -232,7 +232,8 @@ private string AskUserForCloudApplicationName(ProjectDefinition project, List<Cl
                     cloudApplicationName = userResponse.SelectedOption ?? userResponse.NewName;
                 }
 
-                if (_cloudApplicationNameGenerator.IsValidName(cloudApplicationName))
+                if (!string.IsNullOrEmpty(cloudApplicationName) &&
+                    _cloudApplicationNameGenerator.IsValidName(cloudApplicationName))
                     return cloudApplicationName;
 
                 PrintInvalidStackNameMessage();
@@ -358,7 +359,7 @@ private void DisplayOptionSetting(Recommendation recommendation, OptionSettingIt
         {
             var value = recommendation.GetOptionSettingValue(optionSetting);
 
-            Type typeHintResponseType = null;
+            Type? typeHintResponseType = null;
             if (optionSetting.Type == OptionSettingValueType.Object)
             {
                 var typeHintResponseTypeFullName = $"AWS.Deploy.CLI.TypeHintResponses.{optionSetting.TypeHint}TypeHintResponse";
@@ -374,14 +375,14 @@ private async Task ConfigureDeployment(Recommendation recommendation, OptionSett
             _toolInteractiveService.WriteLine($"{setting.Name}:");
             _toolInteractiveService.WriteLine($"{setting.Description}");
 
-            var currentValue = recommendation.GetOptionSettingValue(setting);
-            object settingValue = null;
+            object currentValue = recommendation.GetOptionSettingValue(setting);
+            object? settingValue = null;
             if (setting.AllowedValues?.Count > 0)
             {
-                var userInputConfig = new UserInputConfiguration<string>
+                var userInputConfig = new UserInputConfiguration<string>(
+                    x => setting.ValueMapping.ContainsKey(x) ? setting.ValueMapping[x] : x,
+                    x => x.Equals(currentValue))
                 {
-                    DisplaySelector = x => setting.ValueMapping.ContainsKey(x) ? setting.ValueMapping[x] : x,
-                    DefaultSelector = x => x.Equals(currentValue),
                     CreateNew = false
                 };
 
@@ -404,7 +405,7 @@ private async Task ConfigureDeployment(Recommendation recommendation, OptionSett
                     {
                         case OptionSettingValueType.String:
                         case OptionSettingValueType.Int:
-                            settingValue = _consoleUtilities.AskUserForValue(string.Empty, currentValue?.ToString(), allowEmpty: true, resetValue: recommendation.GetOptionSettingDefaultValue<string>(setting));
+                            settingValue = _consoleUtilities.AskUserForValue(string.Empty, currentValue.ToString() ?? "", allowEmpty: true, resetValue: recommendation.GetOptionSettingDefaultValue<string>(setting) ?? "");
                             break;
                         case OptionSettingValueType.Bool:
                             var answer = _consoleUtilities.AskYesNoQuestion(string.Empty, recommendation.GetOptionSettingValue(setting).ToString());
@@ -434,18 +435,18 @@ private async Task ConfigureDeployment(Recommendation recommendation, OptionSett
         /// This allows to use a generic implementation to display Object type option setting values without casting the response to
         /// the specific TypeHintResponse type.
         /// </summary>
-        private void DisplayValue(Recommendation recommendation, OptionSettingItem optionSetting, int optionSettingNumber, int optionSettingsCount, Type typeHintResponseType, DisplayOptionSettingsMode mode)
+        private void DisplayValue(Recommendation recommendation, OptionSettingItem optionSetting, int optionSettingNumber, int optionSettingsCount, Type? typeHintResponseType, DisplayOptionSettingsMode mode)
         {
-            object displayValue = null;
-            Dictionary<string, object> objectValues = null;
+            object? displayValue = null;
+            Dictionary<string, object>? objectValues = null;
             if (typeHintResponseType != null)
             {
                 var methodInfo = typeof(Recommendation)
-                    .GetMethod(nameof(Recommendation.GetOptionSettingValue), 1, new[] { typeof(OptionSettingItem), typeof(bool) });
+                    .GetMethod(nameof(Recommendation.GetOptionSettingValue), 1, new[] { typeof(OptionSettingItem) });
                 var genericMethodInfo = methodInfo?.MakeGenericMethod(typeHintResponseType);
-                var response = genericMethodInfo?.Invoke(recommendation, new object[] { optionSetting, false });
+                var response = genericMethodInfo?.Invoke(recommendation, new object[] { optionSetting });
 
-                displayValue = ((IDisplayable)response)?.ToDisplayString();
+                displayValue = ((IDisplayable?)response)?.ToDisplayString();
             }
             else
             {

src/AWS.Deploy.CLI/Commands/TypeHints/BeanstalkApplicationCommand.cs

@@ -1,6 +1,7 @@
 // Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
+using System;
 using System.Threading.Tasks;
 using Amazon.ElasticBeanstalk.Model;
 using AWS.Deploy.CLI.TypeHintResponses;
@@ -27,21 +28,21 @@ public async Task<object> Execute(Recommendation recommendation, OptionSettingIt
             var applications = await _awsResourceQueryer.ListOfElasticBeanstalkApplications();
             var currentTypeHintResponse = recommendation.GetOptionSettingValue<BeanstalkApplicationTypeHintResponse>(optionSetting);
 
-            var userInputConfiguration = new UserInputConfiguration<ApplicationDescription>
+            var userInputConfiguration = new UserInputConfiguration<ApplicationDescription>(
+                app => app.ApplicationName,
+                app => app.ApplicationName.Equals(currentTypeHintResponse?.ApplicationName),
+                currentTypeHintResponse.ApplicationName)
             {
-                DisplaySelector = app => app.ApplicationName,
-                DefaultSelector = app => app.ApplicationName.Equals(currentTypeHintResponse?.ApplicationName),
                 AskNewName = true,
-                DefaultNewName = currentTypeHintResponse.ApplicationName
             };
 
             var userResponse = _consoleUtilities.AskUserToChooseOrCreateNew(applications, "Select Elastic Beanstalk application to deploy to:", userInputConfiguration);
 
-            return new BeanstalkApplicationTypeHintResponse
-            {
-                CreateNew = userResponse.CreateNew,
-                ApplicationName = userResponse.SelectedOption?.ApplicationName ?? userResponse.NewName
-            };
+            return new BeanstalkApplicationTypeHintResponse(
+                userResponse.CreateNew,
+                userResponse.SelectedOption?.ApplicationName ?? userResponse.NewName
+                    ?? throw new UserPromptForNameReturnedNullException("The user response for a new application name was null.")
+                );
         }
     }
 }

src/AWS.Deploy.CLI/Commands/TypeHints/BeanstalkEnvironmentCommand.cs

@@ -32,8 +32,9 @@ public async Task<object> Execute(Recommendation recommendation, OptionSettingIt
                 options: environments.Select(env => env.EnvironmentName),
                 title: "Select Elastic Beanstalk environment to deploy to:",
                 askNewName: true,
-                defaultNewName: currentValue.ToString());
-            return userResponse.SelectedOption ?? userResponse.NewName;
+                defaultNewName: currentValue.ToString() ?? "");
+            return userResponse.SelectedOption ?? userResponse.NewName
+                ?? throw new UserPromptForNameReturnedNullException("The user response for a new environment name was null.");
         }
     }
 }

src/AWS.Deploy.CLI/Commands/TypeHints/DockerBuildArgsCommand.cs

@@ -24,7 +24,7 @@ public Task<object> Execute(Recommendation recommendation, OptionSettingItem opt
                     string.Empty,
                     recommendation.GetOptionSettingValue<string>(optionSetting),
                     allowEmpty: true,
-                    resetValue: recommendation.GetOptionSettingDefaultValue<string>(optionSetting),
+                    resetValue: recommendation.GetOptionSettingDefaultValue<string>(optionSetting) ?? "",
                     // validators:
                     buildArgs => ValidateBuildArgs(buildArgs))
                 .ToString()

src/AWS.Deploy.CLI/Commands/TypeHints/DockerExecutionDirectoryCommand.cs

@@ -24,7 +24,7 @@ public Task<object> Execute(Recommendation recommendation, OptionSettingItem opt
                     string.Empty,
                     recommendation.GetOptionSettingValue<string>(optionSetting),
                     allowEmpty: true,
-                    resetValue: recommendation.GetOptionSettingDefaultValue<string>(optionSetting),
+                    resetValue: recommendation.GetOptionSettingDefaultValue<string>(optionSetting) ?? "",
                     // validators:
                     executionDirectory => ValidateExecutionDirectory(executionDirectory));
 

src/AWS.Deploy.CLI/Commands/TypeHints/DotnetBeanstalkPlatformArnCommand.cs

@@ -26,16 +26,16 @@ public async Task<object> Execute(Recommendation recommendation, OptionSettingIt
             var currentValue = recommendation.GetOptionSettingValue(optionSetting);
             var platformArns = await _awsResourceQueryer.GetElasticBeanstalkPlatformArns();
 
-            var userInputConfiguration = new UserInputConfiguration<PlatformSummary>
+            var userInputConfiguration = new UserInputConfiguration<PlatformSummary>(
+                platform => $"{platform.PlatformBranchName} v{platform.PlatformVersion}",
+                platform => platform.PlatformArn.Equals(currentValue))
             {
-                DisplaySelector = platform => $"{platform.PlatformBranchName} v{platform.PlatformVersion}",
-                DefaultSelector = platform => platform.PlatformArn.Equals(currentValue),
                 CreateNew = false
             };
 
             var userResponse = _consoleUtilities.AskUserToChooseOrCreateNew(platformArns, "Select the Platform to use:", userInputConfiguration);
 
-            return userResponse.SelectedOption?.PlatformArn;
+            return userResponse.SelectedOption?.PlatformArn!;
         }
     }
 }

src/AWS.Deploy.CLI/Commands/TypeHints/DotnetPublishArgsCommand.cs

@@ -21,9 +21,9 @@ public Task<object> Execute(Recommendation recommendation, OptionSettingItem opt
             var settingValue = _consoleUtilities
                 .AskUserForValue(
                     string.Empty,
-                    recommendation.GetOptionSettingValue(optionSetting).ToString(),
+                    recommendation.GetOptionSettingValue<string>(optionSetting),
                     allowEmpty: true,
-                    resetValue: recommendation.GetOptionSettingDefaultValue<string>(optionSetting),
+                    resetValue: recommendation.GetOptionSettingDefaultValue<string>(optionSetting) ?? "",
                     // validators:
                     publishArgs =>
                         (publishArgs.Contains("-o ") || publishArgs.Contains("--output "))

src/AWS.Deploy.CLI/Commands/TypeHints/DotnetPublishBuildConfigurationCommand.cs

@@ -23,7 +23,7 @@ public Task<object> Execute(Recommendation recommendation, OptionSettingItem opt
                     string.Empty,
                     recommendation.GetOptionSettingValue<string>(optionSetting),
                     allowEmpty: false,
-                    resetValue: recommendation.GetOptionSettingDefaultValue<string>(optionSetting));
+                    resetValue: recommendation.GetOptionSettingDefaultValue<string>(optionSetting) ?? "");
             recommendation.DeploymentBundle.DotnetPublishBuildConfiguration = settingValue;
             return Task.FromResult<object>(settingValue);
         }

src/AWS.Deploy.CLI/Commands/TypeHints/EC2KeyPairCommand.cs

@@ -27,10 +27,11 @@ public async Task<object> Execute(Recommendation recommendation, OptionSettingIt
             var currentValue = recommendation.GetOptionSettingValue(optionSetting);
             var keyPairs = await _awsResourceQueryer.ListOfEC2KeyPairs();
 
-            var userInputConfiguration = new UserInputConfiguration<KeyPairInfo>
+            var userInputConfiguration = new UserInputConfiguration<KeyPairInfo>(
+                kp => kp.KeyName,
+                kp => kp.KeyName.Equals(currentValue)
+                )
             {
-                DisplaySelector = kp => kp.KeyName,
-                DefaultSelector = kp => kp.KeyName.Equals(currentValue),
                 AskNewName = true,
                 EmptyOption = true,
                 CurrentValue = currentValue
@@ -49,7 +50,8 @@ public async Task<object> Execute(Recommendation recommendation, OptionSettingIt
                 }
                 else
                 {
-                    settingValue = userResponse.SelectedOption?.KeyName ?? userResponse.NewName;
+                    settingValue = userResponse.SelectedOption?.KeyName ?? userResponse.NewName ??
+                        throw new UserPromptForNameReturnedNullException("The user prompt for a new EC2 Key Pair name was null or empty.");
                 }
 
                 if (userResponse.CreateNew && !string.IsNullOrEmpty(userResponse.NewName))
@@ -73,7 +75,7 @@ public async Task<object> Execute(Recommendation recommendation, OptionSettingIt
                 break;
             }
 
-            return settingValue;
+            return settingValue ?? "";
         }
     }
 }

src/AWS.Deploy.CLI/Commands/TypeHints/ECSClusterCommand.cs

@@ -26,22 +26,20 @@ public async Task<object> Execute(Recommendation recommendation, OptionSettingIt
             var clusters = await _awsResourceQueryer.ListOfECSClusters();
             var currentTypeHintResponse = recommendation.GetOptionSettingValue<ECSClusterTypeHintResponse>(optionSetting);
 
-            var userInputConfiguration = new UserInputConfiguration<Cluster>
+            var userInputConfiguration = new UserInputConfiguration<Cluster>(
+                cluster => cluster.ClusterName,
+                cluster => cluster.ClusterArn.Equals(currentTypeHintResponse?.ClusterArn),
+                currentTypeHintResponse.NewClusterName)
             {
-                DisplaySelector = cluster => cluster.ClusterName,
-                DefaultSelector = cluster => cluster.ClusterArn.Equals(currentTypeHintResponse?.ClusterArn),
-                AskNewName = true,
-                DefaultNewName = currentTypeHintResponse.NewClusterName
+                AskNewName = true
             };
 
             var userResponse = _consoleUtilities.AskUserToChooseOrCreateNew(clusters, "Select ECS cluster to deploy to:", userInputConfiguration);
 
-            return new ECSClusterTypeHintResponse
-            {
-                CreateNew = userResponse.CreateNew,
-                ClusterArn = userResponse.SelectedOption?.ClusterArn ?? string.Empty,
-                NewClusterName = userResponse.NewName
-            };
+            return new ECSClusterTypeHintResponse(
+                userResponse.CreateNew,
+                userResponse.SelectedOption?.ClusterArn ?? string.Empty,
+                userResponse.NewName ?? string.Empty);
         }
     }
 }