Use null-coalescing assignment in /remoting and /hostifaces (PowerShell#17728)

Author: Molkree

src/System.Management.Automation/engine/hostifaces/AsyncResult.cs

@@ -85,10 +85,7 @@ public WaitHandle AsyncWaitHandle
                 {
                     lock (SyncObject)
                     {
-                        if (_completedWaitHandle == null)
-                        {
-                            _completedWaitHandle = new ManualResetEvent(IsCompleted);
-                        }
+                        _completedWaitHandle ??= new ManualResetEvent(IsCompleted);
                     }
                 }
 

src/System.Management.Automation/engine/hostifaces/LocalConnection.cs

@@ -84,10 +84,7 @@ public override PSPrimitiveDictionary GetApplicationPrivateData()
             {
                 lock (this.SyncRoot)
                 {
-                    if (_applicationPrivateData == null)
-                    {
-                        _applicationPrivateData = new PSPrimitiveDictionary();
-                    }
+                    _applicationPrivateData ??= new PSPrimitiveDictionary();
                 }
             }
 
@@ -768,10 +765,7 @@ internal void LogEngineHealthEvent(Exception exception,
         /// </remarks>
         internal PipelineThread GetPipelineThread()
         {
-            if (_pipelineThread == null)
-            {
-                _pipelineThread = new PipelineThread(this.ApartmentState);
-            }
+            _pipelineThread ??= new PipelineThread(this.ApartmentState);
 
             return _pipelineThread;
         }

src/System.Management.Automation/engine/hostifaces/MshHostUserInterface.cs

@@ -1090,10 +1090,7 @@ internal static TranscriptionOption GetSystemTranscriptOption(TranscriptionOptio
                 // This way, multiple runspaces opened by the same process will share the same transcript.
                 lock (s_systemTranscriptLock)
                 {
-                    if (systemTranscript == null)
-                    {
-                        systemTranscript = PSHostUserInterface.GetTranscriptOptionFromSettings(transcription, currentTranscript);
-                    }
+                    systemTranscript ??= PSHostUserInterface.GetTranscriptOptionFromSettings(transcription, currentTranscript);
                 }
             }
 

src/System.Management.Automation/engine/hostifaces/PSDataCollection.cs

@@ -1322,12 +1322,9 @@ internal WaitHandle WaitHandle
                 {
                     lock (SyncObject)
                     {
-                        if (_readWaitHandle == null)
-                        {
-                            // Create the handle signaled if there are objects in the buffer
-                            // or the buffer has been closed.
-                            _readWaitHandle = new ManualResetEvent(_data.Count > 0 || !_isOpen);
-                        }
+                        // Create the handle signaled if there are objects in the buffer
+                        // or the buffer has been closed.
+                        _readWaitHandle ??= new ManualResetEvent(_data.Count > 0 || !_isOpen);
                     }
                 }
 

src/System.Management.Automation/engine/hostifaces/PSTask.cs

@@ -1536,12 +1536,9 @@ public Debugger Debugger
         {
             get
             {
-                if (_jobDebuggerWrapper == null)
-                {
-                    _jobDebuggerWrapper = new PSTaskChildDebugger(
-                        _task.Debugger,
-                        this.Name);
-                }
+                _jobDebuggerWrapper ??= new PSTaskChildDebugger(
+                    _task.Debugger,
+                    this.Name);
 
                 return _jobDebuggerWrapper;
             }

src/System.Management.Automation/engine/hostifaces/PowerShell.cs

@@ -762,10 +762,7 @@ internal void InitForRemotePipeline(CommandCollection command, ObjectStreamBase
 
             // create the client remote powershell for remoting
             // communications
-            if (RemotePowerShell == null)
-            {
-                RemotePowerShell = new ClientRemotePowerShell(this, ((RunspacePool)_rsConnection).RemoteRunspacePoolInternal);
-            }
+            RemotePowerShell ??= new ClientRemotePowerShell(this, ((RunspacePool)_rsConnection).RemoteRunspacePoolInternal);
 
             // If we get here, we don't call 'Invoke' or any of it's friends on 'this', instead we serialize 'this' in PowerShell.ToPSObjectForRemoting.
             // Without the following two steps, we'll be missing the 'ExtraCommands' on the serialized instance of 'this'.
@@ -804,10 +801,7 @@ internal void InitForRemotePipelineConnect(ObjectStreamBase inputstream, ObjectS
 
             RedirectShellErrorOutputPipe = redirectShellErrorOutputPipe;
 
-            if (RemotePowerShell == null)
-            {
-                RemotePowerShell = new ClientRemotePowerShell(this, ((RunspacePool)_rsConnection).RemoteRunspacePoolInternal);
-            }
+            RemotePowerShell ??= new ClientRemotePowerShell(this, ((RunspacePool)_rsConnection).RemoteRunspacePoolInternal);
 
             if (!RemotePowerShell.Initialized)
             {
@@ -2236,10 +2230,7 @@ internal void InvokeWithDebugger(
             {
                 if (addToHistory)
                 {
-                    if (settings == null)
-                    {
-                        settings = new PSInvocationSettings();
-                    }
+                    settings ??= new PSInvocationSettings();
 
                     settings.AddToHistory = true;
                 }
@@ -3544,10 +3535,7 @@ private void BatchInvocationCallback(IAsyncResult result)
                         break;
                 }
 
-                if (objs == null)
-                {
-                    objs = _batchAsyncResult.Output;
-                }
+                objs ??= _batchAsyncResult.Output;
 
                 DoRemainingBatchCommands(objs);
             }

src/System.Management.Automation/engine/hostifaces/RunspacePoolInternal.cs

@@ -231,10 +231,7 @@ internal virtual PSPrimitiveDictionary GetApplicationPrivateData()
             {
                 lock (this.syncObject)
                 {
-                    if (_applicationPrivateData == null)
-                    {
-                        _applicationPrivateData = new PSPrimitiveDictionary();
-                    }
+                    _applicationPrivateData ??= new PSPrimitiveDictionary();
                 }
             }
 

src/System.Management.Automation/engine/remoting/client/Job.cs

@@ -633,10 +633,7 @@ public IList<Job> ChildJobs
                 {
                     lock (syncObject)
                     {
-                        if (_childJobs == null)
-                        {
-                            _childJobs = new List<Job>();
-                        }
+                        _childJobs ??= new List<Job>();
                     }
                 }
 
@@ -3371,13 +3368,10 @@ protected void ProcessJobFailure(ExecutionCmdletHelper helper, out Exception fai
                     }
                 }
 
-                if (failureException == null)
-                {
-                    failureException = new RuntimeException(
-                        PSRemotingErrorInvariants.FormatResourceString(
-                            RemotingErrorIdStrings.RemoteRunspaceOpenUnknownState,
-                            runspace.RunspaceStateInfo.State));
-                }
+                failureException ??= new RuntimeException(
+                    PSRemotingErrorInvariants.FormatResourceString(
+                        RemotingErrorIdStrings.RemoteRunspaceOpenUnknownState,
+                        runspace.RunspaceStateInfo.State));
 
                 failureErrorRecord = new ErrorRecord(failureException, targetObject,
                                 fullyQualifiedErrorId, ErrorCategory.OpenError,

src/System.Management.Automation/engine/remoting/client/Job2.cs

@@ -93,8 +93,7 @@ public List<CommandParameterCollection> StartParameters
                 {
                     lock (_syncobject)
                     {
-                        if (_parameters == null)
-                            _parameters = new List<CommandParameterCollection>();
+                        _parameters ??= new List<CommandParameterCollection>();
                     }
                 }
 

src/System.Management.Automation/engine/remoting/client/RunspaceRef.cs

@@ -208,12 +208,9 @@ internal Pipeline CreatePipeline(string line, bool addToHistory, bool useNestedP
             }
 
             // If that didn't work out fall-back to the traditional approach.
-            if (pipeline == null)
-            {
-                pipeline = useNestedPipelines ?
-                    _runspaceRef.Value.CreateNestedPipeline(line, addToHistory) :
-                    _runspaceRef.Value.CreatePipeline(line, addToHistory);
-            }
+            pipeline ??= useNestedPipelines ?
+                _runspaceRef.Value.CreateNestedPipeline(line, addToHistory) :
+                _runspaceRef.Value.CreatePipeline(line, addToHistory);
 
             // Add robust connection callback if this is a pushed runspace.
             RemotePipeline remotePipeline = pipeline as RemotePipeline;