Enable nullable on AttachVS (#3671)

src/AttachVS/AttachVs.cs

@@ -10,8 +10,6 @@
 using System.Runtime.InteropServices.ComTypes;
 using System.Threading;
 
-#nullable disable
-
 namespace Microsoft.TestPlatform.AttachVS;
 
 internal class DebuggerUtility
@@ -25,20 +23,23 @@ internal static bool AttachVSToProcess(int? pid, int? vsPid)
                 Trace($"FAIL: Pid is null.");
                 return false;
             }
+
             var process = Process.GetProcessById(pid.Value);
-            Trace($"Starting with pid '{pid}({process?.ProcessName})', and vsPid '{vsPid}'");
+            Trace($"Starting with pid '{pid}({process.ProcessName})', and vsPid '{vsPid}'");
             Trace($"Using pid: {pid} to get parent VS.");
             var vs = GetVsFromPid(Process.GetProcessById(vsPid ?? process.Id));
 
             if (vs != null)
             {
                 Trace($"Parent VS is {vs.ProcessName} ({vs.Id}).");
                 AttachTo(process, vs);
+                return true;
             }
-            else
-            {
-                Trace($"Parent VS not found, finding the first VS that started.");
-                var processes = Process.GetProcesses().Where(p => p.ProcessName == "devenv").Select(p =>
+
+            Trace($"Parent VS not found, finding the first VS that started.");
+            var firstVs = Process.GetProcesses()
+                .Where(p => p.ProcessName == "devenv")
+                .Select(p =>
                 {
                     try
                     {
@@ -48,19 +49,26 @@ internal static bool AttachVSToProcess(int? pid, int? vsPid)
                     {
                         return null;
                     }
-                }).Where(p => p != null && !p.HasExited).OrderBy(p => p.StartTime).ToList();
+                })
+                .Where(p => p != null && !p.HasExited)
+                .OrderBy(p => p!.StartTime)
+                .FirstOrDefault();
 
-                var firstVs = processes.FirstOrDefault();
+            if (firstVs != null)
+            {
                 Trace($"Found VS {firstVs.Process.Id}");
                 AttachTo(process, firstVs.Process);
+                return true;
             }
-            return true;
+
+            Trace("Could not find any started VS.");
         }
         catch (Exception ex)
         {
             Trace($"ERROR: {ex}, {ex.StackTrace}");
-            return false;
         }
+
+        return false;
     }
 
     private static void AttachTo(Process process, Process vs)
@@ -79,9 +87,9 @@ private static void AttachTo(Process process, Process vs)
 
     private static bool AttachVs(Process vs, int pid)
     {
-        IBindCtx bindCtx = null;
-        IRunningObjectTable runninObjectTable = null;
-        IEnumMoniker enumMoniker = null;
+        IBindCtx? bindCtx = null;
+        IRunningObjectTable? runninObjectTable = null;
+        IEnumMoniker? enumMoniker = null;
         try
         {
             var r = CreateBindCtx(0, out bindCtx);
@@ -183,18 +191,18 @@ private static bool AttachVs(Process vs, int pid)
         }
     }
 
-    private static Process GetVsFromPid(Process process)
+    private static Process? GetVsFromPid(Process process)
     {
         var parent = process;
         while (!IsVsOrNull(parent))
         {
-            parent = GetParentProcess(parent);
+            parent = GetParentProcess(parent!);
         }
 
         return parent;
     }
 
-    private static bool IsVsOrNull(Process process)
+    private static bool IsVsOrNull(Process? process)
     {
         if (process == null)
         {
@@ -219,57 +227,61 @@ private static bool IsCorrectParent(Process currentProcess, Process parent)
     {
         try
         {
-            // Parent needs to start before the child, otherwise it might be a different process 
+            // Parent needs to start before the child, otherwise it might be a different process
             // that is just reusing the same PID.
             if (parent.StartTime <= currentProcess.StartTime)
             {
                 return true;
             }
 
             Trace($"Process {parent.ProcessName} ({parent.Id}) is not a valid parent because it started after the current process.");
-            return false;
         }
         catch
         {
             // Access denied or process exited while we were holding the Process object.
-            return false;
         }
+
+        return false;
     }
 
-    private static Process GetParentProcess(Process process)
+    private static Process? GetParentProcess(Process process)
     {
-        int id;
-        try
-        {
-            var handle = process.Handle;
-            var res = NtQueryInformationProcess(handle, 0, out var pbi, Marshal.SizeOf<PROCESS_BASIC_INFORMATION>(), out int size);
-
-            var p = res != 0 ? -1 : pbi.InheritedFromUniqueProcessId.ToInt32();
-
-            id = p;
-        }
-        catch
-        {
-            id = -1;
-        }
-
-        Process parent = null;
+        int id = GetParentProcessId(process);
         if (id != -1)
         {
             try
             {
-                parent = Process.GetProcessById(id);
+                var parent = Process.GetProcessById(id);
+                if (IsCorrectParent(process, parent))
+                    return parent;
             }
             catch
             {
                 // throws when parent no longer runs
             }
         }
 
-        return IsCorrectParent(process, parent) ? parent : null;
+        return null;
+
+        static int GetParentProcessId(Process process)
+        {
+            try
+            {
+                var handle = process.Handle;
+                var res = NtQueryInformationProcess(handle, 0, out var pbi, Marshal.SizeOf<PROCESS_BASIC_INFORMATION>(), out int size);
+
+                var p = res != 0 ? -1 : pbi.InheritedFromUniqueProcessId.ToInt32();
+
+                return p;
+            }
+            catch
+            {
+                return -1;
+            }
+        }
     }
 
-    private static void Trace(string message, [CallerMemberName] string methodName = null)
+    private static void Trace(string message, [CallerMemberName] string? methodName = null)
     {
         System.Diagnostics.Trace.WriteLine($"[AttachVS]{methodName}: {message}");
     }

src/AttachVS/Program.cs

@@ -5,13 +5,11 @@
 using System.Diagnostics;
 using System.Linq;
 
-#nullable disable
-
 namespace Microsoft.TestPlatform.AttachVS;
 
 internal class Program
 {
-    static void Main(string[] args)
+    static void Main(string[] args!!)
     {
         Trace.Listeners.Add(new ConsoleTraceListener());