Add Roslyn analyzer to check results are used (#2443)

As seen in #2441, it is easy to drop return values of updated entities accidentally.

This PR adds a Roslyn Analyzer which will detect when return values are unused. To explicitly ignore a value you can drop it with `_ = …;`

Closes #2442.

src/ApiService/.editorconfig

@@ -162,3 +162,6 @@ dotnet_diagnostic.CA1848.severity = none
 # allow throwing base "Exception" class, since it's done a lot
 # TODO: improve this
 dotnet_diagnostic.CA2201.severity = suggestion
+
+# ignore this custom diagnostic about "complex" code
+dotnet_diagnostic.CSE006.severity = none

src/ApiService/ApiService/ApiService.csproj

@@ -44,6 +44,7 @@
     <PackageReference Include="Scriban" Version="5.5.0" />
     <PackageReference Include="Octokit" Version="2.0.1" />
     <PackageReference Include="Microsoft.TeamFoundationServer.Client" Version="19.209.0-preview" />
+    <PackageReference Include="SmartAnalyzers.CSharpExtensions.Annotations" Version="4.2.7" />
   </ItemGroup>
   <ItemGroup>
     <None Update="host.json">
@@ -60,4 +61,8 @@
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </EmbeddedResource>
   </ItemGroup>
+
+  <ItemGroup>
+    <AdditionalFiles Include="../CSharpExtensions.json" />
+  </ItemGroup>
 </Project>

src/ApiService/ApiService/Functions/AgentCommands.cs

@@ -52,7 +52,7 @@ public class AgentCommands {
 
         var message = await _context.NodeMessageOperations.GetEntityAsync(nodeCommand.MachineId.ToString(), nodeCommand.MessageId);
         if (message != null) {
-            await _context.NodeMessageOperations.Delete(message);
+            await _context.NodeMessageOperations.Delete(message).IgnoreResult();
         } else {
             _log.WithTag("Command", "DELETE").Verbose($"failed to find machine id {nodeCommand.MachineId} for message {nodeCommand.MessageId}");
         }

src/ApiService/ApiService/Functions/AgentEvents.cs

@@ -73,12 +73,14 @@ public class AgentEvents {
         if (ev.State == NodeState.Free) {
             if (node.ReimageRequested || node.DeleteRequested) {
                 _log.Info($"stopping free node with reset flags: {machineId}");
+                // discard result: node not used after this point
                 _ = await _context.NodeOperations.Stop(node);
                 return null;
             }
 
             if (await _context.NodeOperations.CouldShrinkScaleset(node)) {
                 _log.Info($"stopping free node to resize scaleset: {machineId}");
+                // discard result: node not used after this point
                 _ = await _context.NodeOperations.SetHalt(node);
                 return null;
             }
@@ -87,6 +89,7 @@ public class AgentEvents {
         if (ev.State == NodeState.Init) {
             if (node.DeleteRequested) {
                 _log.Info($"stopping node (init and delete_requested): {machineId}");
+                // discard result: node not used after this point
                 _ = await _context.NodeOperations.Stop(node);
                 return null;
             }
@@ -95,6 +98,7 @@ public class AgentEvents {
             // they send 'init' with reimage_requested, it's because the node was reimaged
             // successfully.
             node = node with { ReimageRequested = false, InitializedAt = DateTimeOffset.UtcNow };
+            // discard result: node not used after this point
             _ = await _context.NodeOperations.SetState(node, ev.State);
             return null;
         }
@@ -129,7 +133,7 @@ public class AgentEvents {
                     // Other states we would want to preserve are excluded by the
                     // outermost conditional check.
                     if (task.State != TaskState.Running && task.State != TaskState.SettingUp) {
-                        await _context.TaskOperations.SetState(task, TaskState.SettingUp);
+                        task = await _context.TaskOperations.SetState(task, TaskState.SettingUp);
                     }
 
                     var nodeTask = new NodeTasks(
@@ -155,7 +159,8 @@ public class AgentEvents {
             // if tasks are running on the node when it reports as Done
             // those are stopped early
             await _context.NodeOperations.MarkTasksStoppedEarly(node, error);
-            await _context.NodeOperations.ToReimage(node, done: true);
+            // discard result: node not used after this point
+            _ = await _context.NodeOperations.ToReimage(node, done: true);
         }
 
         return null;
@@ -193,8 +198,8 @@ public class AgentEvents {
         }
 
         if (!node.State.ReadyForReset()) {
+            // discard result: node not used after this point
             _ = await _context.NodeOperations.SetState(node, NodeState.Busy);
-            // node unused after this point
         }
 
         var nodeTask = new NodeTasks(
@@ -212,7 +217,7 @@ public class AgentEvents {
         }
 
         _log.Info($"task started on node. machine_id:{machineId} job_id:{task.JobId} task_id:{task.TaskId}");
-        await _context.TaskOperations.SetState(task, TaskState.Running);
+        task = await _context.TaskOperations.SetState(task, TaskState.Running);
 
         var taskEvent = new TaskEvent(
             TaskId: task.TaskId,

src/ApiService/ApiService/Functions/Pool.cs

@@ -41,7 +41,8 @@ public class Pool {
             return await _context.RequestHandling.NotOk(r, poolResult.ErrorV, "pool stop");
         }
 
-        await _context.PoolOperations.SetShutdown(poolResult.OkV, Now: request.OkV.Now);
+        // discard result: not used after this point
+        _ = await _context.PoolOperations.SetShutdown(poolResult.OkV, Now: request.OkV.Now);
         return await RequestHandling.Ok(r, true);
     }
 

src/ApiService/ApiService/Functions/Proxy.cs

@@ -134,14 +134,18 @@ public class Proxy {
                 "ProxyReset");
         }
 
-        var proxyList = await _context.ProxyOperations.SearchByPartitionKeys(new[] { $"{request.OkV.Region}" }).ToListAsync();
+        bool any = false;
-
+        {
-        foreach (var proxy in proxyList) {
+            var proxyList = _context.ProxyOperations.SearchByPartitionKeys(new[] { $"{request.OkV.Region}" });
-            await _context.ProxyOperations.SetState(proxy, VmState.Stopping);
+            await foreach (var proxy in proxyList) {
+                any = true;
+                // ignoring result, proxyList not used outside this block
+                _ = await _context.ProxyOperations.SetState(proxy, VmState.Stopping);
+            }
         }
 
         var response = req.CreateResponse(HttpStatusCode.OK);
-        await response.WriteAsJsonAsync(new BoolResult(proxyList.Any()));
+        await response.WriteAsJsonAsync(new BoolResult(any));
         return response;
     }
 

src/ApiService/ApiService/Functions/Scaleset.cs

@@ -43,6 +43,7 @@ public class Scaleset {
         }
 
         var scaleset = scalesetResult.OkV;
+        // result ignored: not used after this point
         _ = await _context.ScalesetOperations.SetShutdown(scaleset, request.OkV.Now);
         return await RequestHandling.Ok(req, true);
     }

src/ApiService/ApiService/Functions/TimerProxy.cs

@@ -16,7 +16,7 @@ public class TimerProxy {
 
         var proxyOperations = _context.ProxyOperations;
         var scalesetOperations = _context.ScalesetOperations;
-        var nsgOpertions = _context.NsgOperations;
+        var nsgOperations = _context.NsgOperations;
 
         var proxies = await proxyOperations.QueryAsync().ToListAsync();
 
@@ -69,14 +69,14 @@ public class TimerProxy {
             // since we do not support bring your own NSG
             var nsgName = Nsg.NameFromRegion(region);
 
-            if (await nsgOpertions.GetNsg(nsgName) != null) {
+            if (await nsgOperations.GetNsg(nsgName) != null) {
                 var network = await Network.Init(region, _context);
 
                 var subnet = await network.GetSubnet();
                 if (subnet != null) {
                     var vnet = await network.GetVnet();
                     if (vnet != null) {
-                        var result = await nsgOpertions.AssociateSubnet(nsgName, vnet, subnet);
+                        var result = await nsgOperations.AssociateSubnet(nsgName, vnet, subnet);
                         if (!result.OkV) {
                             _logger.Error($"Failed to associate NSG and subnet due to {result.ErrorV} in region {region}");
                         }
@@ -86,10 +86,10 @@ public class TimerProxy {
         }
         // if there are NSGs with name same as the region that they are allocated
         // and have no NIC associated with it then delete the NSG
-        await foreach (var nsg in nsgOpertions.ListNsgs()) {
+        await foreach (var nsg in nsgOperations.ListNsgs()) {
-            if (nsgOpertions.OkToDelete(regions, nsg.Data.Location!, nsg.Data.Name)) {
+            if (nsgOperations.OkToDelete(regions, nsg.Data.Location!, nsg.Data.Name)) {
                 if (nsg.Data.NetworkInterfaces.Count == 0 && nsg.Data.Subnets.Count == 0) {
-                    if (!await nsgOpertions.StartDeleteNsg(nsg.Data.Name)) {
+                    if (!await nsgOperations.StartDeleteNsg(nsg.Data.Name)) {
                         _logger.Warning($"failed to start deleting NSG {nsg.Data.Name}");
                     }
                 }

src/ApiService/ApiService/Functions/TimerRepro.cs

@@ -14,20 +14,25 @@ public class TimerRepro {
 
     [Function("TimerRepro")]
     public async Async.Task Run([TimerTrigger("00:00:30")] TimerInfo myTimer) {
+        var expiredVmIds = new HashSet<Guid>();
+        {
             var expired = _onefuzzContext.ReproOperations.SearchExpired();
             await foreach (var repro in expired) {
                 _log.Info($"stopping repro: {repro.VmId}");
+                _ = expiredVmIds.Add(repro.VmId);
+                // ignoring result: value not used later
                 _ = await _onefuzzContext.ReproOperations.Stopping(repro);
             }
-
+        }
-        var expiredVmIds = expired.Select(repro => repro?.VmId);
 
         await foreach (var repro in _onefuzzContext.ReproOperations.SearchStates(VmStateHelper.NeedsWork)) {
-            if (await expiredVmIds.ContainsAsync(repro.VmId)) {
+            if (expiredVmIds.Contains(repro.VmId)) {
                 // this VM already got processed during the expired phase
                 continue;
             }
+
             _log.Info($"update repro: {repro.VmId}");
+            // ignoring result: value not used later
             _ = await _onefuzzContext.ReproOperations.ProcessStateUpdates(repro);
         }
     }

src/ApiService/ApiService/Functions/TimerRetention.cs

@@ -54,7 +54,7 @@ public class TimerRetention {
                 select container.Name;
 
             foreach (var c in containerNames) {
-                usedContainers.Add(c);
+                _ = usedContainers.Add(c);
             }
         }
 

src/ApiService/ApiService/Functions/TimerWorkers.cs

@@ -18,19 +18,21 @@ public class TimerWorkers {
     private async Async.Task ProcessScalesets(Service.Scaleset scaleset) {
         _log.Verbose($"checking scaleset for updates: {scaleset.ScalesetId}");
 
-        await _scaleSetOps.UpdateConfigs(scaleset);
+        scaleset = await _scaleSetOps.UpdateConfigs(scaleset);
         var r = await _scaleSetOps.SyncAutoscaleSettings(scaleset);
         if (!r.IsOk) {
             _log.Error($"failed to sync auto scale settings due to {r.ErrorV}");
         }
 
         // if the scaleset is touched during cleanup, don't continue to process it
-        if (await _scaleSetOps.CleanupNodes(scaleset)) {
+        var (touched, ss) = await _scaleSetOps.CleanupNodes(scaleset);
+        if (touched) {
             _log.Verbose($"scaleset needed cleanup: {scaleset.ScalesetId}");
             return;
         }
 
-        await _scaleSetOps.SyncScalesetSize(scaleset);
+        scaleset = ss;
+        scaleset = await _scaleSetOps.SyncScalesetSize(scaleset);
         _ = await _scaleSetOps.ProcessStateUpdate(scaleset);
     }
 

src/ApiService/ApiService/HttpClient.cs

@@ -17,7 +17,7 @@ public class Request {
     }
 
     private async Task<HttpResponseMessage> Send(HttpMethod method, Uri url, HttpContent? content = null, IDictionary<string, string>? headers = null) {
-        var request = new HttpRequestMessage(method: method, requestUri: url);
+        using var request = new HttpRequestMessage(method: method, requestUri: url);
 
         if (_auth is not null) {
             var (tokenType, accessToken) = await _auth();

src/ApiService/ApiService/Program.cs

@@ -166,7 +166,10 @@ public class Program {
         var storageAccount = serviceConfig.OneFuzzFuncStorage;
         if (storageAccount is not null) {
             var tableClient = await storage.GetTableServiceClientForAccount(storageAccount);
-            await Async.Task.WhenAll(toCreate.Select(t => tableClient.CreateTableIfNotExistsAsync(serviceConfig.OneFuzzStoragePrefix + t.Name)));
+            await Async.Task.WhenAll(toCreate.Select(async t => {
+                // don't care if it was created or not
+                _ = await tableClient.CreateTableIfNotExistsAsync(serviceConfig.OneFuzzStoragePrefix + t.Name);
+            }));
         }
     }
 }

src/ApiService/ApiService/onefuzzlib/Config.cs

@@ -462,7 +462,7 @@ public class Config : IConfig {
         var containers = new Dictionary<ContainerType, List<Container>>();
 
         foreach (var container in config.Containers) {
-            if (exist.Contains(container.Name)) {
+            if (!exist.Add(container.Name)) {
                 continue;
             }
 
@@ -470,8 +470,6 @@ public class Config : IConfig {
                 return ResultVoid<TaskConfigError>.Error(new TaskConfigError($"missing container: {container.Name}"));
             }
 
-            _ = exist.Add(container.Name);
-
             if (!containers.ContainsKey(container.Type)) {
                 containers.Add(container.Type, new List<Container>());
             }

src/ApiService/ApiService/onefuzzlib/ConfigOperations.cs

@@ -25,7 +25,7 @@ public class ConfigOperations : Orm<InstanceConfig>, IConfigOperations {
     private static readonly InstanceConfigCacheKey _key = new(); // singleton key
     public Task<InstanceConfig> Fetch()
         => _cache.GetOrCreateAsync(_key, async entry => {
-            entry.SetAbsoluteExpiration(TimeSpan.FromMinutes(10)); // cached for 10 minutes
+            entry = entry.SetAbsoluteExpiration(TimeSpan.FromMinutes(10)); // cached for 10 minutes
             var key = _context.ServiceConfiguration.OneFuzzInstanceName ?? throw new Exception("Environment variable ONEFUZZ_INSTANCE_NAME is not set");
             return await GetEntityAsync(key, key);
         });
@@ -49,9 +49,11 @@ public class ConfigOperations : Orm<InstanceConfig>, IConfigOperations {
                 _log.WithHttpStatus(r.ErrorV).Error($"Failed to replace instance config record");
             }
         }
+
         if (r.IsOk) {
-            _cache.Set(_key, newConfig);
+            _ = _cache.Set(_key, newConfig);
         }
+
         await _context.Events.SendEvent(new EventInstanceConfigUpdated(newConfig));
     }
 }

src/ApiService/ApiService/onefuzzlib/Containers.cs

@@ -166,7 +166,7 @@ public class Containers : IContainers {
 
     public async Async.Task SaveBlob(Container container, string name, string data, StorageType storageType) {
         var client = await FindContainer(container, storageType) ?? throw new Exception($"unable to find container: {container} - {storageType}");
-        await client.GetBlobClient(name).UploadAsync(new BinaryData(data), overwrite: true);
+        _ = await client.GetBlobClient(name).UploadAsync(new BinaryData(data), overwrite: true);
     }
 
     public virtual Async.Task<Guid> GetInstanceId() => _getInstanceId.Value;

src/ApiService/ApiService/onefuzzlib/DiskOperations.cs

@@ -25,7 +25,7 @@ public class DiskOperations : IDiskOperations {
             _logTracer.Info($"deleting disks {resourceGroup} : {name}");
             var disk = await _creds.GetResourceGroupResource().GetDiskAsync(name);
             if (disk != null) {
-                await disk.Value.DeleteAsync(WaitUntil.Started);
+                _ = await disk.Value.DeleteAsync(WaitUntil.Started);
                 return true;
             }
         } catch (Exception e) {

src/ApiService/ApiService/onefuzzlib/Extension.cs

@@ -371,8 +371,8 @@ public class Extensions : IExtensions {
     public async Task<Dictionary<string, VirtualMachineExtensionData>> ReproExtensions(AzureLocation region, Os reproOs, Guid reproId, ReproConfig reproConfig, Container? setupContainer) {
         // TODO: what about contents of repro.ps1 / repro.sh?
         var report = await _context.Reports.GetReport(reproConfig.Container, reproConfig.Path);
-        report.EnsureNotNull($"invalid report: {reproConfig}");
+        var checkedReport = report.EnsureNotNull($"invalid report: {reproConfig}");
-        report?.InputBlob.EnsureNotNull("unable to perform reproduction without an input blob");
+        var inputBlob = checkedReport.InputBlob.EnsureNotNull("unable to perform reproduction without an input blob");
 
         var commands = new List<string>();
         if (setupContainer != null) {
@@ -395,8 +395,8 @@ public class Extensions : IExtensions {
                 BlobSasPermissions.Read
             ),
             await _context.Containers.GetFileSasUrl(
-                report?.InputBlob?.Container!,
+                inputBlob.Container,
-                report?.InputBlob?.Name!,
+                inputBlob.Name,
                 StorageType.Corpus,
                 BlobSasPermissions.Read
             )

src/ApiService/ApiService/onefuzzlib/JobOperations.cs

@@ -78,13 +78,13 @@ public class JobOperations : StatefulOrm<Job, JobState, JobOperations>, IJobOper
             Query.EqualEnum("state", JobState.Enabled)
         });
 
-        var jobs = this.QueryAsync(filter);
+        await foreach (var job in QueryAsync(filter)) {
-
-        await foreach (var job in jobs) {
             await foreach (var task in _context.TaskOperations.QueryAsync(Query.PartitionKey(job.JobId.ToString()))) {
                 await _context.TaskOperations.MarkFailed(task, new Error(ErrorCode.TASK_FAILED, new[] { "job never not start" }));
             }
             _logTracer.Info($"stopping job that never started: {job.JobId}");
+
+            // updated result ignored: not used after this loop
             _ = await _context.JobOperations.Stopping(job);
         }
     }

src/ApiService/ApiService/onefuzzlib/NodeMessageOperations.cs

@@ -40,7 +40,7 @@ public class NodeMessageOperations : Orm<NodeMessage>, INodeMessageOperations {
     }
 
     public async Async.Task SendMessage(Guid machineId, NodeCommand message, string? messageId = null) {
-        messageId = messageId ?? EntityBase.NewSortedKey;
+        messageId ??= EntityBase.NewSortedKey;
         var r = await Insert(new NodeMessage(machineId, messageId, message));
         if (!r.IsOk) {
             _logTracer.WithHttpStatus(r.ErrorV).Error($"failed to insert message with id: {messageId} for machine id: {machineId} message: {message}");

src/ApiService/ApiService/onefuzzlib/NotificationOperations.cs

@@ -54,8 +54,8 @@ public class NotificationOperations : Orm<Notification>, INotificationOperations
         await foreach (var (task, containers) in GetQueueTasks()) {
             if (containers.Contains(container)) {
                 _logTracer.Info($"queuing input {container} {filename} {task.TaskId}");
-                var url = _context.Containers.GetFileSasUrl(container, filename, StorageType.Corpus, BlobSasPermissions.Read | BlobSasPermissions.Delete);
+                var url = await _context.Containers.GetFileSasUrl(container, filename, StorageType.Corpus, BlobSasPermissions.Read | BlobSasPermissions.Delete);
-                await _context.Queue.SendMessage(task.TaskId.ToString(), url?.ToString() ?? "", StorageType.Corpus);
+                await _context.Queue.SendMessage(task.TaskId.ToString(), url.ToString(), StorageType.Corpus);
             }
         }
 

src/ApiService/ApiService/onefuzzlib/NsgOperations.cs

@@ -84,7 +84,7 @@ namespace Microsoft.OneFuzz.Service {
             _logTracer.Info($"dissociating nic {nic.Data.Name} with nsg: {_context.Creds.GetBaseResourceGroup()} {nsg.Name}");
             nic.Data.NetworkSecurityGroup = null;
             try {
-                await _context.Creds.GetResourceGroupResource()
+                _ = await _context.Creds.GetResourceGroupResource()
                     .GetNetworkInterfaces()
                     .CreateOrUpdateAsync(WaitUntil.Started, nic.Data.Name, nic.Data);
             } catch (Exception e) {
@@ -183,11 +183,10 @@ namespace Microsoft.OneFuzz.Service {
             }
 
             try {
-                await _context.Creds.GetResourceGroupResource().GetNetworkSecurityGroups().CreateOrUpdateAsync(
+                _ = await _context.Creds.GetResourceGroupResource().GetNetworkSecurityGroups().CreateOrUpdateAsync(
                     WaitUntil.Started,
                     name,
-                    nsgParams
+                    nsgParams);
-                );
             } catch (RequestFailedException ex) {
                 if (IsConcurrentRequestError(ex.Message)) {
                     // _logTracer.Debug($"create NSG had conflicts with concurrent request, ignoring {ex}");
@@ -291,9 +290,8 @@ namespace Microsoft.OneFuzz.Service {
             _logTracer.Info($"associating nic {nic.Data.Name} with nsg: {_context.Creds.GetBaseResourceGroup()} {nsg.Data.Name}");
 
             try {
-                await _context.Creds.GetResourceGroupResource().GetNetworkInterfaces().CreateOrUpdateAsync(
+                _ = await _context.Creds.GetResourceGroupResource().GetNetworkInterfaces().CreateOrUpdateAsync(
-                    WaitUntil.Started, nic.Data.Name, nic.Data
+                    WaitUntil.Started, nic.Data.Name, nic.Data);
-                );
             } catch (RequestFailedException ex) {
                 if (IsConcurrentRequestError(ex.Message)) {
                     // _logTracer.Debug($"associate NSG with NIC had conflicts with concurrent request, ignoring {ex}");
@@ -312,11 +310,10 @@ namespace Microsoft.OneFuzz.Service {
             _logTracer.Info($"updating nsg {_context.Creds.GetBaseResourceGroup()}:{nsg.Location}:{nsg.Name}");
 
             try {
-                await _context.Creds.GetResourceGroupResource().GetNetworkSecurityGroups().CreateOrUpdateAsync(
+                _ = await _context.Creds.GetResourceGroupResource().GetNetworkSecurityGroups().CreateOrUpdateAsync(
                     WaitUntil.Started,
                     nsg.Name,
-                    nsg
+                    nsg);
-                );
             } catch (RequestFailedException ex) {
                 if (IsConcurrentRequestError(ex.Message)) {
                     //_logTracer.Debug($"create NSG had conflicts with concurrent request, ignoring {ex}");

src/ApiService/ApiService/onefuzzlib/PoolOperations.cs

@@ -198,7 +198,8 @@ public class PoolOperations : StatefulOrm<Pool, PoolState, PoolOperations>, IPoo
 
         if (nodes is not null) {
             await foreach (var node in nodes) {
-                await _context.NodeOperations.SetShutdown(node);
+                // ignoring updated result - nodes not returned
+                _ = await _context.NodeOperations.SetShutdown(node);
             }
         }
 
@@ -231,7 +232,8 @@ public class PoolOperations : StatefulOrm<Pool, PoolState, PoolOperations>, IPoo
 
         if (nodes is not null) {
             await foreach (var node in nodes) {
-                await _context.NodeOperations.SetHalt(node);
+                // updated value ignored: 'nodes' is not returned
+                _ = await _context.NodeOperations.SetHalt(node);
             }
         }
 

src/ApiService/ApiService/onefuzzlib/ProxyForwardOperations.cs

@@ -54,7 +54,7 @@ public class ProxyForwardOperations : Orm<ProxyForward>, IProxyForwardOperations
         var firstEntry = entries.FirstOrDefault();
         if (firstEntry != null) {
             var updated = firstEntry with { EndTime = DateTimeOffset.UtcNow + TimeSpan.FromHours(duration) };
-            await this.Update(updated);
+            await Update(updated).IgnoreResult();
             return OneFuzzResult.Ok(updated);
         }
 
@@ -94,8 +94,8 @@ public class ProxyForwardOperations : Orm<ProxyForward>, IProxyForwardOperations
 
         var regions = new HashSet<Region>();
         foreach (var entry in entries) {
-            regions.Add(entry.Region);
+            _ = regions.Add(entry.Region);
-            await Delete(entry);
+            await Delete(entry).IgnoreResult();
         }
 
         return regions;

src/ApiService/ApiService/onefuzzlib/ProxyOperations.cs

@@ -41,8 +41,8 @@ public class ProxyOperations : StatefulOrm<Proxy, VmState, ProxyOperations>, IPr
     }
 
     public async Async.Task<Proxy> GetOrCreate(Region region) {
+        {
             var proxyList = QueryAsync(filter: TableClient.CreateQueryFilter($"region eq {region.String} and outdated eq false"));
-
             await foreach (var proxy in proxyList) {
                 if (IsOutdated(proxy)) {
                     var r1 = await Replace(proxy with { Outdated = true });
@@ -55,8 +55,10 @@ public class ProxyOperations : StatefulOrm<Proxy, VmState, ProxyOperations>, IPr
                 if (!VmStateHelper.Available.Contains(proxy.State)) {
                     continue;
                 }
+
                 return proxy;
             }
+        }
 
         _logTracer.Info($"creating proxy: region:{region}");
         var newProxy = new Proxy(region, Guid.NewGuid(), DateTimeOffset.UtcNow, VmState.Init, await Auth.BuildAuth(_logTracer), null, null, _context.ServiceConfiguration.OneFuzzVersion, null, false);
@@ -305,7 +307,7 @@ public class ProxyOperations : StatefulOrm<Proxy, VmState, ProxyOperations>, IPr
         var stoppedVm = await SetState(proxy, VmState.Stopped);
         _logTracer.Info($"removing proxy: {stoppedVm.Region}");
         await _context.Events.SendEvent(new EventProxyDeleted(stoppedVm.Region, stoppedVm.ProxyId));
-        await Delete(stoppedVm);
+        await Delete(stoppedVm).IgnoreResult();
         return stoppedVm;
     }
 

src/ApiService/ApiService/onefuzzlib/Queue.cs

@@ -44,7 +44,7 @@ public class Queue : IQueue {
     public async Async.Task SendMessage(string name, string message, StorageType storageType, TimeSpan? visibilityTimeout = null, TimeSpan? timeToLive = null) {
         var queue = await GetQueueClient(name, storageType);
         try {
-            await queue.SendMessageAsync(message, visibilityTimeout: visibilityTimeout, timeToLive: timeToLive);
+            _ = await queue.SendMessageAsync(message, visibilityTimeout: visibilityTimeout, timeToLive: timeToLive);
         } catch (Exception ex) {
             _log.Exception(ex, $"Failed to send message {message}");
             throw;

src/ApiService/ApiService/onefuzzlib/ReproOperations.cs

@@ -108,6 +108,7 @@ public class ReproOperations : StatefulOrm<Repro, VmState, ReproOperations>, IRe
 
     public async Async.Task<Repro> Stopped(Repro repro) {
         _logTracer.Info($"vm stopped: {repro.VmId}");
+        // BUG?: why are we updating repro and then deleting it and returning a new value
         repro = repro with { State = VmState.Stopped };
         var r = await Delete(repro);
         if (!r.IsOk) {
@@ -204,7 +205,7 @@ public class ReproOperations : StatefulOrm<Repro, VmState, ReproOperations>, IRe
             repro = repro with { State = VmState.Running };
         }
 
-        await Replace(repro);
+        await Replace(repro).IgnoreResult();
         return repro;
     }
 

src/ApiService/ApiService/onefuzzlib/RequestAccess.cs

@@ -67,7 +67,7 @@ public class RequestAccess {
         var segments = path.Split("/", StringSplitOptions.RemoveEmptyEntries);
 
         var currentNode = _root;
-        currentNode.Rules.TryGetValue(method, out var currentRule);
+        _ = currentNode.Rules.TryGetValue(method, out var currentRule);
 
         foreach (var currentSegment in segments) {
             if (currentNode.Children.TryGetValue(currentSegment, out var node)) {

src/ApiService/ApiService/onefuzzlib/ScalesetOperations.cs

@@ -10,14 +10,14 @@ public interface IScalesetOperations : IStatefulOrm<Scaleset, ScalesetState> {
 
     IAsyncEnumerable<Scaleset> SearchByPool(PoolName poolName);
 
-    Async.Task UpdateConfigs(Scaleset scaleSet);
+    Async.Task<Scaleset> UpdateConfigs(Scaleset scaleSet);
 
     Async.Task<OneFuzzResult<Scaleset>> GetById(Guid scalesetId);
     IAsyncEnumerable<Scaleset> GetByObjectId(Guid objectId);
 
-    Async.Task<bool> CleanupNodes(Scaleset scaleSet);
+    Async.Task<(bool, Scaleset)> CleanupNodes(Scaleset scaleSet);
 
-    Async.Task SyncScalesetSize(Scaleset scaleset);
+    Async.Task<Scaleset> SyncScalesetSize(Scaleset scaleset);
 
     Async.Task<Scaleset> SetState(Scaleset scaleset, ScalesetState state);
     public Async.Task<List<ScalesetNodeState>> GetNodes(Scaleset scaleset);
@@ -56,11 +56,11 @@ public class ScalesetOperations : StatefulOrm<Scaleset, ScalesetState, ScalesetO
         return QueryAsync(Query.PartitionKey(poolName.String));
     }
 
-    public async Async.Task SyncScalesetSize(Scaleset scaleset) {
+    public async Async.Task<Scaleset> SyncScalesetSize(Scaleset scaleset) {
         // # If our understanding of size is out of sync with Azure, resize the
         // # scaleset to match our understanding.
         if (scaleset.State != ScalesetState.Running) {
-            return;
+            return scaleset;
         }
 
         var size = await _context.VmssOperations.GetVmssSize(scaleset.ScalesetId);
@@ -69,9 +69,10 @@ public class ScalesetOperations : StatefulOrm<Scaleset, ScalesetState, ScalesetO
             //#if the scaleset is missing, this is an indication the scaleset
             //# was manually deleted, rather than having OneFuzz delete it.  As
             //# such, we should go thruogh the process of deleting it.
-            await SetShutdown(scaleset, now: true);
+            scaleset = await SetShutdown(scaleset, now: true);
-            return;
+            return scaleset;
         }
+
         if (size != scaleset.Size) {
             //# Azure auto-scaled us or nodes were manually added/removed
             //# New node state will be synced in cleanup_nodes
@@ -83,6 +84,8 @@ public class ScalesetOperations : StatefulOrm<Scaleset, ScalesetState, ScalesetO
                 _log.WithHttpStatus(replaceResult.ErrorV).Error($"Failed to update scaleset size for scaleset {scaleset.ScalesetId}");
             }
         }
+
+        return scaleset;
     }
 
     public async Async.Task<OneFuzzResultVoid> SyncAutoscaleSettings(Scaleset scaleset) {
@@ -221,37 +224,34 @@ public class ScalesetOperations : StatefulOrm<Scaleset, ScalesetState, ScalesetO
         return updatedScaleset;
     }
 
-    public async Async.Task UpdateConfigs(Scaleset scaleSet) {
+    public async Async.Task<Scaleset> UpdateConfigs(Scaleset scaleSet) {
-        if (scaleSet == null) {
-            _log.Warning("skipping update configs on scaleset, since scaleset is null");
-            return;
-        }
         if (scaleSet.State == ScalesetState.Halt) {
             _log.Info($"{SCALESET_LOG_PREFIX} not updating configs, scalest is set to be deleted. scaleset_id: {scaleSet.ScalesetId}");
-            return;
+            return scaleSet;
         }
+
         if (!scaleSet.NeedsConfigUpdate) {
             _log.Verbose($"{SCALESET_LOG_PREFIX} config update no needed. scaleset_id: {scaleSet.ScalesetId}");
-            return;
+            return scaleSet;
         }
 
         _log.Info($"{SCALESET_LOG_PREFIX} updating scalset configs. scalset_id: {scaleSet.ScalesetId}");
 
         var pool = await _context.PoolOperations.GetByName(scaleSet.PoolName);
-
         if (!pool.IsOk) {
             _log.Error($"{SCALESET_LOG_PREFIX} unable to find pool during config update. pool:{scaleSet.PoolName}, scaleset_id:{scaleSet.ScalesetId}");
-            await SetFailed(scaleSet, pool.ErrorV);
+            scaleSet = await SetFailed(scaleSet, pool.ErrorV);
-            return;
+            return scaleSet;
         }
 
         var extensions = await _context.Extensions.FuzzExtensions(pool.OkV, scaleSet);
 
         var res = await _context.VmssOperations.UpdateExtensions(scaleSet.ScalesetId, extensions);
-
         if (!res.IsOk) {
             _log.Info($"{SCALESET_LOG_PREFIX} unable to update configs {string.Join(',', res.ErrorV.Errors!)}");
         }
+
+        return scaleSet;
     }
 
     public Async.Task<Scaleset> SetShutdown(Scaleset scaleset, bool now)
@@ -488,21 +488,22 @@ public class ScalesetOperations : StatefulOrm<Scaleset, ScalesetState, ScalesetO
     /// </summary>
     /// <param name="scaleSet"></param>
     /// <returns>true if scaleset got modified</returns>
-    public async Async.Task<bool> CleanupNodes(Scaleset scaleSet) {
+    public async Async.Task<(bool, Scaleset)> CleanupNodes(Scaleset scaleSet) {
         _log.Info($"{SCALESET_LOG_PREFIX} cleaning up nodes. scaleset_id {scaleSet.ScalesetId}");
 
         if (scaleSet.State == ScalesetState.Halt) {
             _log.Info($"{SCALESET_LOG_PREFIX} halting scaleset scaleset_id {scaleSet.ScalesetId}");
-            await Halt(scaleSet);
+            scaleSet = await Halt(scaleSet);
-            return true;
+            return (true, scaleSet);
         }
 
         var pool = await _context.PoolOperations.GetByName(scaleSet.PoolName);
         if (!pool.IsOk) {
             _log.Error($"unable to find pool during cleanup {scaleSet.ScalesetId} - {scaleSet.PoolName}");
-            await SetFailed(scaleSet, pool.ErrorV!);
+            scaleSet = await SetFailed(scaleSet, pool.ErrorV!);
-            return true;
+            return (true, scaleSet);
         }
+
         await _context.NodeOperations.ReimageLongLivedNodes(scaleSet.ScalesetId);
 
         //ground truth of existing nodes
@@ -596,7 +597,7 @@ public class ScalesetOperations : StatefulOrm<Scaleset, ScalesetState, ScalesetO
         await ReimageNodes(scaleSet, toReimage.Values, strategy);
         await DeleteNodes(scaleSet, toDelete.Values, strategy);
 
-        return toReimage.Count > 0 || toDelete.Count > 0;
+        return (toReimage.Count > 0 || toDelete.Count > 0, scaleSet);
     }
 
 
@@ -627,7 +628,7 @@ public class ScalesetOperations : StatefulOrm<Scaleset, ScalesetState, ScalesetO
             if (node.DebugKeepNode) {
                 _log.Warning($"{SCALESET_LOG_PREFIX} not reimaging manually overriden node. scaleset_id:{scaleset.ScalesetId} machine_id:{node.MachineId}");
             } else {
-                machineIds.Add(node.MachineId);
+                _ = machineIds.Add(node.MachineId);
             }
         }
 
@@ -641,7 +642,9 @@ public class ScalesetOperations : StatefulOrm<Scaleset, ScalesetState, ScalesetO
                 _log.Info($"{SCALESET_LOG_PREFIX} decommissioning nodes");
                 await Async.Task.WhenAll(nodes
                     .Where(node => machineIds.Contains(node.MachineId))
-                    .Select(node => _context.NodeOperations.ReleaseScaleInProtection(node)));
+                    .Select(async node => {
+                        await _context.NodeOperations.ReleaseScaleInProtection(node).IgnoreResult();
+                    }));
                 return;
 
             case NodeDisposalStrategy.ScaleIn:
@@ -651,7 +654,7 @@ public class ScalesetOperations : StatefulOrm<Scaleset, ScalesetState, ScalesetO
                         .Where(node => machineIds.Contains(node.MachineId))
                         .Select(async node => {
                             await _context.NodeOperations.Delete(node);
-                            await _context.NodeOperations.ReleaseScaleInProtection(node);
+                            await _context.NodeOperations.ReleaseScaleInProtection(node).IgnoreResult();
                         }));
                 } else {
                     _log.Info($"failed to reimage nodes due to {r.ErrorV}");
@@ -680,7 +683,7 @@ public class ScalesetOperations : StatefulOrm<Scaleset, ScalesetState, ScalesetO
             if (node.DebugKeepNode) {
                 _log.Warning($"{SCALESET_LOG_PREFIX} not deleting manually overriden node. scaleset_id:{scaleset.ScalesetId} machine_id:{node.MachineId}");
             } else {
-                machineIds.Add(node.MachineId);
+                _ = machineIds.Add(node.MachineId);
             }
         }
 
@@ -689,7 +692,9 @@ public class ScalesetOperations : StatefulOrm<Scaleset, ScalesetState, ScalesetO
                 _log.Info($"{SCALESET_LOG_PREFIX} decommissioning nodes");
                 await Async.Task.WhenAll(nodes
                     .Where(node => machineIds.Contains(node.MachineId))
-                    .Select(node => _context.NodeOperations.ReleaseScaleInProtection(node)));
+                    .Select(async node => {
+                        await _context.NodeOperations.ReleaseScaleInProtection(node).IgnoreResult();
+                    }));
                 return;
 
             case NodeDisposalStrategy.ScaleIn:
@@ -699,7 +704,7 @@ public class ScalesetOperations : StatefulOrm<Scaleset, ScalesetState, ScalesetO
                     .Where(node => machineIds.Contains(node.MachineId))
                     .Select(async node => {
                         await _context.NodeOperations.Delete(node);
-                        await _context.NodeOperations.ReleaseScaleInProtection(node);
+                        await _context.NodeOperations.ReleaseScaleInProtection(node).IgnoreResult();
                     }));
                 return;
         }
@@ -812,10 +817,10 @@ public class ScalesetOperations : StatefulOrm<Scaleset, ScalesetState, ScalesetO
         }
 
         _logTracer.Info($"{SCALESET_LOG_PREFIX} scaleset shutdown: scaleset_id:{scaleset.ScalesetId} size:{size}");
+        {
             var nodes = _context.NodeOperations.SearchStates(scalesetId: scaleset.ScalesetId);
             // TODO: Parallelization opportunity
-        await foreach (var node in nodes) {
+            await nodes.ForEachAwaitAsync(_context.NodeOperations.SetShutdown);
-            await _context.NodeOperations.SetShutdown(node);
         }
 
         _logTracer.Info($"{SCALESET_LOG_PREFIX} checking for existing auto scale settings {scaleset.ScalesetId}");

src/ApiService/ApiService/onefuzzlib/Scheduler.cs

@@ -44,7 +44,7 @@ public class Scheduler : IScheduler {
                         foreach (var workUnit in workSet.WorkUnits) {
                             var task1 = tasks[workUnit.TaskId];
                             Task task = await _taskOperations.SetState(task1, TaskState.Scheduled);
-                            seen.Add(task.TaskId);
+                            _ = seen.Add(task.TaskId);
                         }
                     }
                 }
@@ -172,17 +172,18 @@ public class Scheduler : IScheduler {
         }
         var setupContainer = task.Config.Containers?.FirstOrDefault(c => c.Type == ContainerType.Setup) ?? throw new Exception($"task missing setup container: task_type = {task.Config.Task.Type}");
 
-        var setupPs1Exist = _containers.BlobExists(setupContainer.Name, "setup.ps1", StorageType.Corpus);
-        var setupShExist = _containers.BlobExists(setupContainer.Name, "setup.sh", StorageType.Corpus);
-
         string? setupScript = null;
-        if (task.Os == Os.Windows && await setupPs1Exist) {
+        if (task.Os == Os.Windows) {
+            if (await _containers.BlobExists(setupContainer.Name, "setup.ps1", StorageType.Corpus)) {
                 setupScript = "setup.ps1";
             }
+        }
 
-        if (task.Os == Os.Linux && await setupShExist) {
+        if (task.Os == Os.Linux) {
+            if (await _containers.BlobExists(setupContainer.Name, "setup.sh", StorageType.Corpus)) {
                 setupScript = "setup.sh";
             }
+        }
 
         var reboot = false;
         var count = 1L;

src/ApiService/ApiService/onefuzzlib/Subnet.cs

@@ -51,11 +51,10 @@ public class Subnet : ISubnet {
         }
 
         try {
-            await _creds.GetResourceGroupResource().GetVirtualNetworks().CreateOrUpdateAsync(
+            _ = await _creds.GetResourceGroupResource().GetVirtualNetworks().CreateOrUpdateAsync(
                 WaitUntil.Started,
                 name,
-                virtualNetParam
+                virtualNetParam);
-            );
         } catch (RequestFailedException ex) {
             _logTracer.Error($"network creation failed: {name}:{region} {{error}}");
             return OneFuzzResultVoid.Error(

src/ApiService/ApiService/onefuzzlib/Utils.cs

@@ -3,8 +3,15 @@
 public static class ObjectExtention {
     public static T EnsureNotNull<T>(this T? thisObject, string message) {
         if (thisObject == null) {
-            throw new ArgumentNullException(message);
+            throw new ArgumentException(message);
         }
+
         return thisObject;
     }
+
+    // Explicitly discards the result value.
+    // In general we should not do this; eventually all call-sites should
+    // be updated.
+    public static Async.Task IgnoreResult<T>(this Async.Task<T> task)
+        => task;
 }

src/ApiService/ApiService/onefuzzlib/VmExtensionWrapper.cs

@@ -19,49 +19,32 @@ namespace Microsoft.OneFuzz.Service {
             if (Location == null) { // EnsureNotNull does not satisfy the nullability checker
                 throw new ArgumentNullException("Location required for VirtualMachineExtension");
             }
-            TypePropertiesType.EnsureNotNull("TypePropertiesType required for VirtualMachineExtension");
-            Publisher.EnsureNotNull("Publisher required for VirtualMachineExtension");
-            TypeHandlerVersion.EnsureNotNull("TypeHandlerVersion required for VirtualMachineExtension");
-            AutoUpgradeMinorVersion.EnsureNotNull("AutoUpgradeMinorVersion required for VirtualMachineExtension");
-
-            var settings = Settings ?? new BinaryData(new Dictionary<string, string>());
-            var protectedSettings = ProtectedSettings ?? new BinaryData(new Dictionary<string, string>());
 
             return (Name!, new VirtualMachineExtensionData(Location.Value) {
-                TypePropertiesType = TypePropertiesType,
+                TypePropertiesType = TypePropertiesType.EnsureNotNull("TypePropertiesType required for VirtualMachineExtension"),
-                Publisher = Publisher,
+                Publisher = Publisher.EnsureNotNull("Publisher required for VirtualMachineExtension"),
-                TypeHandlerVersion = TypeHandlerVersion,
+                TypeHandlerVersion = TypeHandlerVersion.EnsureNotNull("TypeHandlerVersion required for VirtualMachineExtension"),
-                AutoUpgradeMinorVersion = AutoUpgradeMinorVersion,
+                AutoUpgradeMinorVersion = AutoUpgradeMinorVersion.EnsureNotNull("AutoUpgradeMinorVersion required for VirtualMachineExtension"),
                 EnableAutomaticUpgrade = EnableAutomaticUpgrade,
                 ForceUpdateTag = ForceUpdateTag,
-                Settings = settings,
+                Settings = Settings ?? new BinaryData(new Dictionary<string, string>()),
-                ProtectedSettings = protectedSettings
+                ProtectedSettings = ProtectedSettings ?? new BinaryData(new Dictionary<string, string>()),
             });
         }
 
         public VirtualMachineScaleSetExtensionData GetAsVirtualMachineScaleSetExtension() {
-            Name.EnsureNotNull("Name required for VirtualMachineScaleSetExtension");
-            TypePropertiesType.EnsureNotNull("TypePropertiesType required for VirtualMachineScaleSetExtension");
-            Publisher.EnsureNotNull("Publisher required for VirtualMachineScaleSetExtension");
-            TypeHandlerVersion.EnsureNotNull("TypeHandlerVersion required for VirtualMachineScaleSetExtension");
-            AutoUpgradeMinorVersion.EnsureNotNull("AutoUpgradeMinorVersion required for VirtualMachineScaleSetExtension");
-
-            var settings = Settings ?? new BinaryData(new Dictionary<string, string>());
-            var protectedSettings = ProtectedSettings ?? new BinaryData(new Dictionary<string, string>());
-
             return new VirtualMachineScaleSetExtensionData() {
-                Name = Name,
+                Name = Name.EnsureNotNull("Name required for VirtualMachineScaleSetExtension"),
-                TypePropertiesType = TypePropertiesType,
+                TypePropertiesType = TypePropertiesType.EnsureNotNull("TypePropertiesType required for VirtualMachineScaleSetExtension"),
-                Publisher = Publisher,
+                Publisher = Publisher.EnsureNotNull("Publisher required for VirtualMachineScaleSetExtension"),
-                TypeHandlerVersion = TypeHandlerVersion,
+                TypeHandlerVersion = TypeHandlerVersion.EnsureNotNull("TypeHandlerVersion required for VirtualMachineScaleSetExtension"),
-                AutoUpgradeMinorVersion = AutoUpgradeMinorVersion,
+                AutoUpgradeMinorVersion = AutoUpgradeMinorVersion.EnsureNotNull("AutoUpgradeMinorVersion required for VirtualMachineScaleSetExtension"),
                 EnableAutomaticUpgrade = EnableAutomaticUpgrade,
                 ForceUpdateTag = ForceUpdateTag,
-                Settings = settings,
+                Settings = Settings ?? new BinaryData(new Dictionary<string, string>()),
-                ProtectedSettings = protectedSettings
+                ProtectedSettings = ProtectedSettings ?? new BinaryData(new Dictionary<string, string>()),
             };
         }
     }
 
 }
-

src/ApiService/ApiService/onefuzzlib/VmOperations.cs

@@ -100,7 +100,7 @@ public class VmOperations : IVmOperations {
         if (nic != null) {
             _logTracer.Info($"deleting nic {resourceGroup}:{name}");
             if (nic.Data.NetworkSecurityGroup != null && nsg != null) {
-                await _context.NsgOperations.DissociateNic(nsg, nic);
+                _ = await _context.NsgOperations.DissociateNic(nsg, nic);
                 return false;
             }
             await _context.IpOperations.DeleteNic(resourceGroup, name);
@@ -217,7 +217,7 @@ public class VmOperations : IVmOperations {
         var vm = await _context.Creds.GetResourceGroupResource().GetVirtualMachineAsync(vmName);
 
         try {
-            await vm.Value.GetVirtualMachineExtensions().CreateOrUpdateAsync(
+            _ = await vm.Value.GetVirtualMachineExtensions().CreateOrUpdateAsync(
                 WaitUntil.Started,
                 extensionName,
                 extension
@@ -318,11 +318,10 @@ public class VmOperations : IVmOperations {
         }
 
         try {
-            await _context.Creds.GetResourceGroupResource().GetVirtualMachines().CreateOrUpdateAsync(
+            _ = await _context.Creds.GetResourceGroupResource().GetVirtualMachines().CreateOrUpdateAsync(
                 WaitUntil.Started,
                 name,
-                vmParams
+                vmParams);
-            );
         } catch (RequestFailedException ex) {
             if (ex.ErrorCode == "ResourceNotFound" && ex.Message.Contains("The request failed due to conflict with a concurrent request")) {
                 // _logTracer.Debug($"create VM had conflicts with concurrent request, ignoring {ex.ToString()}");

src/ApiService/ApiService/onefuzzlib/VmssOperations.cs

@@ -87,7 +87,7 @@ public class VmssOperations : IVmssOperations {
             var scalesetResource = GetVmssResource(name);
             var patch = new VirtualMachineScaleSetPatch();
             patch.Sku.Capacity = capacity;
-            await scalesetResource.UpdateAsync(WaitUntil.Started, patch);
+            _ = await scalesetResource.UpdateAsync(WaitUntil.Started, patch);
             return OneFuzzResultVoid.Ok;
         } else {
             return OneFuzzResultVoid.Error(canUpdate.ErrorV);
@@ -222,7 +222,7 @@ public class VmssOperations : IVmssOperations {
                 instanceVm.Data.ProtectionPolicy.ProtectFromScaleIn = protectFromScaleIn;
                 var vmCollection = GetVmssResource(name).GetVirtualMachineScaleSetVms();
                 try {
-                    await vmCollection.CreateOrUpdateAsync(WaitUntil.Started, instanceVm.Data.InstanceId, instanceVm.Data);
+                    _ = await vmCollection.CreateOrUpdateAsync(WaitUntil.Started, instanceVm.Data.InstanceId, instanceVm.Data);
                     return OneFuzzResultVoid.Ok;
                 } catch {
                     var msg = $"unable to set protection policy on: {vmId}:{instanceVm.Id}";
@@ -396,7 +396,7 @@ public class VmssOperations : IVmssOperations {
 
     public Async.Task<IReadOnlyList<string>> ListAvailableSkus(Region region)
         => _cache.GetOrCreateAsync<IReadOnlyList<string>>($"compute-skus-{region}", async entry => {
-            entry.SetAbsoluteExpiration(TimeSpan.FromMinutes(10));
+            entry = entry.SetAbsoluteExpiration(TimeSpan.FromMinutes(10));
 
             var sub = _creds.GetSubscriptionResource();
             var skus = sub.GetResourceSkusAsync(filter: TableClient.CreateQueryFilter($"location eq {region.String}"));

src/ApiService/ApiService/onefuzzlib/WebhookOperations.cs

@@ -65,13 +65,14 @@ public class WebhookOperations : Orm<Webhook>, IWebhookOperations {
             headers["X-Onefuzz-Digest"] = digest;
         }
 
-        var client = new Request(_httpFactory.CreateClient());
+        using var httpClient = _httpFactory.CreateClient();
+        var client = new Request(httpClient);
         _logTracer.Info(data);
-        var response = client.Post(url: webhook.Url, json: data, headers: headers);
+        using var response = await client.Post(url: webhook.Url, json: data, headers: headers);
-        var result = response.Result;
+        if (response.StatusCode == HttpStatusCode.Accepted) {
-        if (result.StatusCode == HttpStatusCode.Accepted) {
             return true;
         }
+
         return false;
     }
 

src/ApiService/ApiService/onefuzzlib/notifications/Ado.cs

@@ -170,13 +170,12 @@ container:{container} filename:{filename}";
         public async Async.Task UpdateExisting(WorkItem item, string notificationInfo) {
             if (_config.OnDuplicate.Comment != null) {
                 var comment = await Render(_config.OnDuplicate.Comment);
-                await _client.AddCommentAsync(
+                _ = await _client.AddCommentAsync(
                     new CommentCreate() {
                         Text = comment
                     },
                     _project,
-                    (int)(item.Id!)
+                    (int)(item.Id!));
-                );
             }
 
             var document = new JsonPatchDocument();
@@ -209,7 +208,7 @@ container:{container} filename:{filename}";
             }
 
             if (document.Any()) {
-                await _client.UpdateWorkItemAsync(document, _project, (int)(item.Id!));
+                _ = await _client.UpdateWorkItemAsync(document, _project, (int)(item.Id!));
                 _logTracer.Info($"notify ado: updated work item {item.Id} - {notificationInfo}");
             } else {
                 _logTracer.Info($"notify ado: no update for work item {item.Id} - {notificationInfo}");
@@ -228,13 +227,12 @@ container:{container} filename:{filename}";
 
             if (_config.Comment != null) {
                 var comment = await Render(_config.Comment);
-                await _client.AddCommentAsync(
+                _ = await _client.AddCommentAsync(
                     new CommentCreate() {
                         Text = comment,
                     },
                     _project,
-                    (int)(entry.Id!)
+                    (int)(entry.Id!));
-                );
             }
             return entry;
         }

src/ApiService/ApiService/onefuzzlib/notifications/GithubIssues.cs

@@ -114,17 +114,17 @@ public class GithubIssues : NotificationsBase, IGithubIssues {
         private async Async.Task Update(Issue issue) {
             _logTracer.Info($"updating issue: {issue}");
             if (_config.OnDuplicate.Comment != null) {
-                await _gh.Issue.Comment.Create(issue.Repository.Id, issue.Number, await Render(_config.OnDuplicate.Comment));
+                _ = await _gh.Issue.Comment.Create(issue.Repository.Id, issue.Number, await Render(_config.OnDuplicate.Comment));
             }
             if (_config.OnDuplicate.Labels.Any()) {
                 var labels = await _config.OnDuplicate.Labels.ToAsyncEnumerable()
                     .SelectAwait(async label => await Render(label))
                     .ToArrayAsync();
 
-                await _gh.Issue.Labels.ReplaceAllForIssue(issue.Repository.Id, issue.Number, labels);
+                _ = await _gh.Issue.Labels.ReplaceAllForIssue(issue.Repository.Id, issue.Number, labels);
             }
             if (_config.OnDuplicate.Reopen && issue.State != ItemState.Open) {
-                await _gh.Issue.Update(issue.Repository.Id, issue.Number, new IssueUpdate() {
+                _ = await _gh.Issue.Update(issue.Repository.Id, issue.Number, new IssueUpdate() {
                     State = ItemState.Open
                 });
             }
@@ -140,7 +140,7 @@ public class GithubIssues : NotificationsBase, IGithubIssues {
                 .SelectAwait(async label => await Render(label))
                 .ToHashSetAsync();
 
-            labels.Add("OneFuzz");
+            _ = labels.Add("OneFuzz");
 
             var newIssue = new NewIssue(await Render(_config.Title)) {
                 Body = await Render(_config.Body),
@@ -149,12 +149,10 @@ public class GithubIssues : NotificationsBase, IGithubIssues {
             labels.ToList().ForEach(label => newIssue.Labels.Add(label));
             assignees.ForEach(assignee => newIssue.Assignees.Add(assignee));
 
-            await _gh.Issue.Create(
+            _ = await _gh.Issue.Create(
                 await Render(_config.Organization),
                 await Render(_config.Repository),
-                newIssue
+                newIssue);
-            );
         }
     }
 }
-

src/ApiService/ApiService/onefuzzlib/notifications/NotificationsBase.cs

@@ -42,15 +42,25 @@ public abstract class NotificationsBase {
         private readonly Uri _inputUrl;
         private readonly Uri _reportUrl;
 
-        public static async Async.Task<Renderer> ConstructRenderer(IOnefuzzContext context, Container container, string filename, Report report, Task? task = null, Job? job = null, Uri? targetUrl = null, Uri? inputUrl = null, Uri? reportUrl = null) {
+        public static async Async.Task<Renderer> ConstructRenderer(
+            IOnefuzzContext context,
+            Container container,
+            string filename,
+            Report report,
+            Task? task = null,
+            Job? job = null,
+            Uri? targetUrl = null,
+            Uri? inputUrl = null,
+            Uri? reportUrl = null) {
+
             task ??= await context.TaskOperations.GetByJobIdAndTaskId(report.JobId, report.TaskId);
-            task.EnsureNotNull($"invalid task {report.TaskId}");
+            var checkedTask = task.EnsureNotNull($"invalid task {report.TaskId}");
 
             job ??= await context.JobOperations.Get(report.JobId);
-            job.EnsureNotNull($"invalid job {report.JobId}");
+            var checkedJob = job.EnsureNotNull($"invalid job {report.JobId}");
 
             if (targetUrl == null) {
-                var setupContainer = Scheduler.GetSetupContainer(task?.Config!);
+                var setupContainer = Scheduler.GetSetupContainer(checkedTask.Config);
                 targetUrl = new Uri(context.Containers.AuthDownloadUrl(setupContainer, ReplaceFirstSetup(report.Executable)));
             }
 
@@ -62,9 +72,25 @@ public abstract class NotificationsBase {
                 inputUrl = new Uri(context.Containers.AuthDownloadUrl(report.InputBlob.Container, report.InputBlob.Name));
             }
 
-            return new Renderer(container, filename, report, task!, job!, targetUrl, inputUrl!, reportUrl);
+            return new Renderer(
+                container,
+                filename,
+                report,
+                checkedTask,
+                checkedJob,
+                targetUrl,
+                inputUrl!, // TODO: incorrect
+                reportUrl);
         }
-        public Renderer(Container container, string filename, Report report, Task task, Job job, Uri targetUrl, Uri inputUrl, Uri reportUrl) {
+        public Renderer(
+            Container container,
+            string filename,
+            Report report,
+            Task task,
+            Job job,
+            Uri targetUrl,
+            Uri inputUrl,
+            Uri reportUrl) {
             _report = report;
             _container = container;
             _filename = filename;

src/ApiService/ApiService/onefuzzlib/orm/CustomConverterFactory.cs

@@ -70,7 +70,7 @@ public sealed class CustomEnumConverter<T> : JsonConverter<T> where T : Enum {
                 return false;
             }
 
-            FormatAndAddToCaches(value, options.Encoder, _skipFormat);
+            _ = FormatAndAddToCaches(value, options.Encoder, _skipFormat);
             return true;
         }
     }
@@ -248,7 +248,7 @@ public sealed class PolymorphicConverter<T> : JsonConverter<T> {
                 var newOptions = new JsonSerializerOptions(k);
                 var thisConverter = newOptions.Converters.FirstOrDefault(c => c.GetType() == typeof(PolymorphicConverterFactory));
                 if (thisConverter != null) {
-                    newOptions.Converters.Remove(thisConverter);
+                    _ = newOptions.Converters.Remove(thisConverter);
                 }
 
                 return newOptions;

src/ApiService/ApiService/onefuzzlib/orm/Orm.cs

@@ -138,7 +138,7 @@ namespace ApiService.OneFuzzLib.Orm {
 
 
     public interface IStatefulOrm<T, TState> : IOrm<T> where T : StatefulEntityBase<TState> where TState : Enum {
-        Async.Task<T?> ProcessStateUpdate(T entity);
+        Async.Task<T> ProcessStateUpdate(T entity);
 
         Async.Task<T?> ProcessStateUpdates(T entity, int MaxUpdates = 5);
     }
@@ -201,7 +201,7 @@ namespace ApiService.OneFuzzLib.Orm {
         /// </summary>
         /// <param name="entity"></param>
         /// <returns></returns>
-        public async Async.Task<T?> ProcessStateUpdate(T entity) {
+        public async Async.Task<T> ProcessStateUpdate(T entity) {
             TState state = entity.State;
             var func = GetType().GetMethod(state.ToString()) switch {
                 null => null,
@@ -214,9 +214,8 @@ namespace ApiService.OneFuzzLib.Orm {
                 _logTracer.Info($"processing state update: {typeof(T)} - PartitionKey: {partitionKey} RowKey: {rowKey} - {state}");
                 return await func(entity);
             } else {
-                _logTracer.Info($"State function for state: '{state}' not found on type {typeof(T)}");
+                throw new ArgumentException($"State function for state: '{state}' not found on type {typeof(T)}");
             }
-            return null;
         }
 
         /// <summary>

src/ApiService/ApiService/packages.lock.json

@@ -333,6 +333,12 @@
         "resolved": "2.1.0",
         "contentHash": "1jUT0PwgKO9d9F/X2n762qLp7v/30OpMtJPFRtmjPXUX2/J0lnqiGiSJNNsW3yYTj5StF0Z1yE36TrvtGpcbrg=="
       },
+      "SmartAnalyzers.CSharpExtensions.Annotations": {
+        "type": "Direct",
+        "requested": "[4.2.7, )",
+        "resolved": "4.2.7",
+        "contentHash": "9fRFxTUwPmH7lukckwEvvKawMcP8ObwnOngN8kx5Bx773WHSku1EGa5BIteV07th5553il76fPX7U1xz2bFmuQ=="
+      },
       "System.IdentityModel.Tokens.Jwt": {
         "type": "Direct",
         "requested": "[6.22.1, )",

src/ApiService/CSharpExtensions.json

@@ -0,0 +1,12 @@
+{
+    "$comment1": "See https://github.com/cezarypiatek/CSharpExtensions ",
+    "$comment2": "These types are all 'builders' and okay to ignore the result of",
+    "CSE005": {
+        "IgnoredReturnTypes": [
+            "Microsoft.Azure.Functions.Worker.IFunctionsWorkerApplicationBuilder",
+            "Microsoft.Extensions.DependencyInjection.IServiceCollection",
+            "Moq.Language.Flow.IReturnsResult",
+            "FluentAssertions.AndConstraint"
+        ]
+    }
+}

src/ApiService/IntegrationTests/ContainersTests.cs

@@ -50,7 +50,7 @@ public abstract class ContainersTestBase : FunctionTestBase {
     public async Async.Task CanDelete() {
         var containerName = Container.Parse("test");
         var client = GetContainerClient(containerName);
-        await client.CreateIfNotExistsAsync();
+        _ = await client.CreateIfNotExistsAsync();
 
         var msg = TestHttpRequestData.FromJson("DELETE", new ContainerDelete(containerName));
 
@@ -89,7 +89,7 @@ public abstract class ContainersTestBase : FunctionTestBase {
     public async Async.Task CanPost_Existing() {
         var containerName = Container.Parse("test");
         var client = GetContainerClient(containerName);
-        await client.CreateIfNotExistsAsync();
+        _ = await client.CreateIfNotExistsAsync();
 
         var metadata = new Dictionary<string, string> { { "some", "value" } };
         var msg = TestHttpRequestData.FromJson("POST", new ContainerCreate(containerName, metadata));
@@ -113,7 +113,7 @@ public abstract class ContainersTestBase : FunctionTestBase {
         var containerName = Container.Parse("test");
         {
             var client = GetContainerClient(containerName);
-            await client.CreateIfNotExistsAsync();
+            _ = await client.CreateIfNotExistsAsync();
         }
 
         var msg = TestHttpRequestData.FromJson("GET", new ContainerGet(containerName));
@@ -143,8 +143,8 @@ public abstract class ContainersTestBase : FunctionTestBase {
     public async Async.Task List_Existing() {
         var meta1 = new Dictionary<string, string> { { "key1", "value1" } };
         var meta2 = new Dictionary<string, string> { { "key2", "value2" } };
-        await GetContainerClient(Container.Parse("one")).CreateIfNotExistsAsync(metadata: meta1);
+        _ = await GetContainerClient(Container.Parse("one")).CreateIfNotExistsAsync(metadata: meta1);
-        await GetContainerClient(Container.Parse("two")).CreateIfNotExistsAsync(metadata: meta2);
+        _ = await GetContainerClient(Container.Parse("two")).CreateIfNotExistsAsync(metadata: meta2);
 
         var msg = TestHttpRequestData.Empty("GET"); // this means list all
 
@@ -166,12 +166,12 @@ public abstract class ContainersTestBase : FunctionTestBase {
 
     private static async Async.Task AssertCanCRUD(Uri sasUrl) {
         var client = new BlobContainerClient(sasUrl);
-        await client.UploadBlobAsync("blob", new BinaryData("content")); // create
+        _ = await client.UploadBlobAsync("blob", new BinaryData("content")); // create
         var b = Assert.Single(await client.GetBlobsAsync().ToListAsync()); // list
         using (var s = await client.GetBlobClient(b.Name).OpenReadAsync())
         using (var sr = new StreamReader(s)) {
             Assert.Equal("content", await sr.ReadToEndAsync()); // read
         }
-        await client.DeleteBlobAsync("blob"); // delete
+        using var r = await client.DeleteBlobAsync("blob"); // delete
     }
 }

src/ApiService/IntegrationTests/DownloadTests.cs

@@ -74,8 +74,8 @@ public abstract class DownloadTestBase : FunctionTestBase {
         // set up a file to download
         var containerName = Container.Parse("xxx");
         var container = GetContainerClient(containerName);
-        await container.CreateAsync();
+        _ = await container.CreateAsync();
-        await container.UploadBlobAsync("yyy", new BinaryData("content"));
+        _ = await container.UploadBlobAsync("yyy", new BinaryData("content"));
 
         var req = TestHttpRequestData.Empty("GET");
         var url = new UriBuilder(req.Url) { Query = "container=xxx&filename=yyy" }.Uri;

src/ApiService/IntegrationTests/InfoTests.cs

@@ -50,8 +50,8 @@ public abstract class InfoTestBase : FunctionTestBase {
         var instanceId = Guid.NewGuid().ToString();
         var baseConfigContainer = WellKnownContainers.BaseConfig;
         var containerClient = GetContainerClient(baseConfigContainer);
-        await containerClient.CreateAsync();
+        _ = await containerClient.CreateAsync();
-        await containerClient.GetBlobClient("instance_id").UploadAsync(new BinaryData(instanceId));
+        _ = await containerClient.GetBlobClient("instance_id").UploadAsync(new BinaryData(instanceId));
 
         var auth = new TestEndpointAuthorization(RequestType.User, Logger, Context);
         var func = new Info(auth, Context);

src/ApiService/IntegrationTests/IntegrationTests.csproj

@@ -23,4 +23,7 @@
     <ProjectReference Include="..\ApiService\ApiService.csproj" />
   </ItemGroup>
 
+  <ItemGroup>
+    <AdditionalFiles Include="../CSharpExtensions.json" />
+  </ItemGroup>
 </Project>

src/ApiService/IntegrationTests/_FunctionTestBase.cs

@@ -70,7 +70,7 @@ public abstract class FunctionTestBase : IAsyncLifetime {
     }
 
     protected static string BodyAsString(HttpResponseData data) {
-        data.Body.Seek(0, SeekOrigin.Begin);
+        _ = data.Body.Seek(0, SeekOrigin.Begin);
         using var sr = new StreamReader(data.Body);
         return sr.ReadToEnd();
     }
@@ -85,7 +85,7 @@ public abstract class FunctionTestBase : IAsyncLifetime {
             .Where(c => c.IsDeleted != true)
             .Select(async container => {
                 try {
-                    await blobClient.DeleteBlobContainerAsync(container.Name);
+                    using var _ = await blobClient.DeleteBlobContainerAsync(container.Name);
                     Logger.Info($"cleaned up container {container.Name}");
                 } catch (Exception ex) {
                     // swallow any exceptions: this is a best-effort attempt to cleanup
@@ -100,7 +100,7 @@ public abstract class FunctionTestBase : IAsyncLifetime {
                 .QueryAsync(filter: Query.StartsWith("TableName", _storagePrefix))
                 .Select(async table => {
                     try {
-                        await tableClient.DeleteTableAsync(table.Name);
+                        using var _ = await tableClient.DeleteTableAsync(table.Name);
                         Logger.Info($"cleaned up table {table.Name}");
                     } catch (Exception ex) {
                         // swallow any exceptions: this is a best-effort attempt to cleanup

src/ApiService/IntegrationTests/packages.lock.json

@@ -1185,6 +1185,11 @@
         "resolved": "2.1.0",
         "contentHash": "1jUT0PwgKO9d9F/X2n762qLp7v/30OpMtJPFRtmjPXUX2/J0lnqiGiSJNNsW3yYTj5StF0Z1yE36TrvtGpcbrg=="
       },
+      "SmartAnalyzers.CSharpExtensions.Annotations": {
+        "type": "Transitive",
+        "resolved": "4.2.7",
+        "contentHash": "9fRFxTUwPmH7lukckwEvvKawMcP8ObwnOngN8kx5Bx773WHSku1EGa5BIteV07th5553il76fPX7U1xz2bFmuQ=="
+      },
       "System.AppContext": {
         "type": "Transitive",
         "resolved": "4.3.0",
@@ -2309,6 +2314,7 @@
           "Octokit": "2.0.1",
           "Scriban": "5.5.0",
           "Semver": "2.1.0",
+          "SmartAnalyzers.CSharpExtensions.Annotations": "4.2.7",
           "System.IdentityModel.Tokens.Jwt": "6.22.1",
           "System.Linq.Async": "6.0.1",
           "TaskTupleAwaiter": "2.0.0"

src/ApiService/Tests/OrmModelsTest.cs

@@ -691,7 +691,7 @@ namespace Tests {
         ITestOutputHelper _output;
 
         public OrmModelsTest(ITestOutputHelper output) {
-            Arb.Register<OrmArb>();
+            _ = Arb.Register<OrmArb>();
             _output = output;
         }
 
@@ -773,7 +773,7 @@ namespace Tests {
         ITestOutputHelper _output;
 
         public OrmJsonSerialization(ITestOutputHelper output) {
-            Arb.Register<OrmArb>();
+            _ = Arb.Register<OrmArb>();
             _output = output;
         }
 

src/ApiService/Tests/OrmTest.cs

@@ -141,10 +141,10 @@ namespace Tests {
 
             var json = JsonNode.Parse(tableEntity.GetString("the_object"))?.AsObject() ?? throw new InvalidOperationException("Could not parse objec");
 
-            json.TryGetPropertyValue("the_name", out var theName);
+            Assert.True(json.TryGetPropertyValue("the_name", out var theName));
-            json.TryGetPropertyValue("the_enum", out var theEnum);
+            Assert.True(json.TryGetPropertyValue("the_enum", out var theEnum));
-            json.TryGetPropertyValue("the_flag", out var theFlag);
+            Assert.True(json.TryGetPropertyValue("the_flag", out var theFlag));
-            json.TryGetPropertyValue("the_enum_value", out var theEnumValue);
+            Assert.True(json.TryGetPropertyValue("the_enum_value", out var theEnumValue));
 
             Assert.Equal(entity1.TheObject.TheName, theName?.GetValue<string>());
             Assert.Equal("the_two", theEnum?.GetValue<string>());

src/ApiService/Tests/RequestAccessTests.cs

@@ -59,9 +59,9 @@ public class RequestAccessTests {
 
     [Fact]
     public void TestAddingRuleOnSamePath() {
-        Assert.Throws<RuleConflictException>(() => {
+        _ = Assert.Throws<RuleConflictException>(() => {
             var guid1 = Guid.NewGuid();
-            RequestAccess.Build(
+            _ = RequestAccess.Build(
                 new Dictionary<string, ApiAccessRule>{
                     { "a/b/c", new ApiAccessRule(
                         Methods: new[]{"get"},

src/ApiService/Tests/SchedulerTests.cs

@@ -129,7 +129,7 @@ public class SchedulerTests {
         Assert.Equal(buckets.Count, bucketCount);
 
         foreach (var task in tasks) {
-            Assert.Single(buckets, b => b.Contains(task));
+            _ = Assert.Single(buckets, b => b.Contains(task));
         }
     }
 }

src/ApiService/Tests/Tests.csproj

@@ -25,4 +25,7 @@
     <ProjectReference Include="..\ApiService\ApiService.csproj" />
   </ItemGroup>
 
+  <ItemGroup>
+    <AdditionalFiles Include="../CSharpExtensions.json" />
+  </ItemGroup>
 </Project>

src/ApiService/Tests/packages.lock.json

@@ -1234,6 +1234,11 @@
         "resolved": "2.1.0",
         "contentHash": "1jUT0PwgKO9d9F/X2n762qLp7v/30OpMtJPFRtmjPXUX2/J0lnqiGiSJNNsW3yYTj5StF0Z1yE36TrvtGpcbrg=="
       },
+      "SmartAnalyzers.CSharpExtensions.Annotations": {
+        "type": "Transitive",
+        "resolved": "4.2.7",
+        "contentHash": "9fRFxTUwPmH7lukckwEvvKawMcP8ObwnOngN8kx5Bx773WHSku1EGa5BIteV07th5553il76fPX7U1xz2bFmuQ=="
+      },
       "System.AppContext": {
         "type": "Transitive",
         "resolved": "4.3.0",
@@ -2436,6 +2441,7 @@
           "Octokit": "2.0.1",
           "Scriban": "5.5.0",
           "Semver": "2.1.0",
+          "SmartAnalyzers.CSharpExtensions.Annotations": "4.2.7",
           "System.IdentityModel.Tokens.Jwt": "6.22.1",
           "System.Linq.Async": "6.0.1",
           "TaskTupleAwaiter": "2.0.0"