Restore terminal cursor visibility on exit in collect-linux

src/Tools/dotnet-trace/CommandLine/Commands/CollectLinuxCommand.cs

@@ -82,6 +82,8 @@ internal int CollectLinux(CollectLinuxArgs args)
 
             int ret = (int)ReturnCode.TracingError;
             string scriptPath = null;
+            bool cursorVisibilityChanged = false;
+            bool originalCursorVisible = false;
             try
             {
                 if (args.Probe)
@@ -101,7 +103,15 @@ internal int CollectLinux(CollectLinuxArgs args)
                 }
 
                 args.Ct.Register(() => stopTracing = true);
-                Console.CursorVisible = false;
+
+                // Only hide cursor if output is not redirected
+                if (!Console.IsOutputRedirected)
+                {
+                    originalCursorVisible = Console.CursorVisible;
+                    Console.CursorVisible = false;
+                    cursorVisibilityChanged = true;
+                }
+
                 byte[] command = BuildRecordTraceArgs(args, out scriptPath);
 
                 if (args.Duration != default)
@@ -135,6 +145,12 @@ internal int CollectLinux(CollectLinuxArgs args)
             }
             finally
             {
+                // Restore cursor visibility to its original state if we changed it
+                if (cursorVisibilityChanged)
+                {
+                    Console.CursorVisible = originalCursorVisible;
+                }
+
                 if (!string.IsNullOrEmpty(scriptPath))
                 {
                     try

src/tests/dotnet-trace/CollectLinuxCommandFunctionalTests.cs

@@ -222,6 +222,53 @@ public void CollectLinuxCommand_NotSupported_OnNonLinux()
             });
         }
 
+        [ConditionalFact(nameof(IsCollectLinuxSupported))]
+        public void CollectLinuxCommand_RestoresCursorVisibility_OnSuccess()
+        {
+            MockConsole console = new(200, 30, _outputHelper);
+            console.CursorVisible = true;
+
+            int exitCode = Run(TestArgs(), console);
+
+            // Cursor should be restored to visible after command completes
+            Assert.True(console.CursorVisible, "Cursor should be visible after command completes");
+        }
+
+        [ConditionalFact(nameof(IsCollectLinuxSupported))]
+        public void CollectLinuxCommand_RestoresCursorVisibility_OnError()
+        {
+            MockConsole console = new(200, 30, _outputHelper);
+            console.CursorVisible = true;
+
+            var handler = new CollectLinuxCommandHandler(console);
+            // Simulate an error by throwing an exception in the RecordTraceInvoker
+            handler.RecordTraceInvoker = (cmd, len, cb) => {
+                throw new InvalidOperationException("Simulated error");
+            };
+
+            int exitCode = handler.CollectLinux(TestArgs());
+
+            // Cursor should be restored to visible even when an error occurs
+            Assert.True(console.CursorVisible, "Cursor should be visible after error");
+            Assert.Equal((int)ReturnCode.TracingError, exitCode);
+        }
+
+        [ConditionalTheory(nameof(IsCollectLinuxSupported))]
+        [InlineData(true)]
+        [InlineData(false)]
+        public void CollectLinuxCommand_DoesNotChangeCursorVisibility_WhenOutputIsRedirected(bool initialCursorVisible)
+        {
+            MockConsole console = new(200, 30, _outputHelper);
+            console.CursorVisible = initialCursorVisible;
+            console.IsOutputRedirected = true;
+
+            int exitCode = Run(TestArgs(), console);
+
+            // When output is redirected, the command should not change cursor visibility,
+            // so the cursor should remain in its original state.
+            Assert.Equal(initialCursorVisible, console.CursorVisible);
+        }
+
         private static int Run(object args, MockConsole console)
         {
             var handler = new CollectLinuxCommandHandler(console);